How to Fix a Weil McLain Boiler that Keeps Running

In this video, I show you how to diagnose and repair a Weil McLain gas boiler that keeps running and maintaining temperature even when the thermostats are turned off.
Relay can be ordered here: amzn.to/2yTHFey

[@fixitwithzim]

Link in description to purchase the replacement relay I used in this video. Thanks for supporting my channel!

[@donaldkrog9223]

Steve...A BIG THANK YOU!!!! And for everyone the posts these kinds of videos. Your diagnosis of this heater problem was EXACTLY what was wrong with my unit. I had the heater firing up all the time trying to maintain 190 degrees and also the boiler would sometimes reach temps above 220 degrees and banging the pipes and controls valves in the middle of the night waking me up. I thought that this boiler was done ready for disposal. However watching your video and doing so troubleshooting I replaced the latching relay and my problems and boiler is working like new. Thank you! Thank you! Thank you! Keep these videos coming you are educating all of us and our equipment making us better homeowners!

[@jonrich1164]

your video was amazing and extremely helpful. after coming home from work to a 90 degrees house and climbing, the thermostats were set to 65, I found your video when I Google a search. after watching the video, I tapped 3 or 4 times and it shut off. I pulled the part and ran to the part store, 10.49 later, I replaced the part and everything worked perfectly...Thank you so much...

[@fixitwithzim]

John Richmond A little late but you're welcome. Thanks for the comment.

[@trikerjon]

Thanks you solved my problem . We were out of town all winter and came back in May. It was 105 degrees in the house and the gas boiler was running. I turned the thermostats off and it was still running. I will order that part and hopefully solve my problem. Thank you

[@RxMusicGroup]

Thank you so much for this video. A big outfit / well known group couldn't fix the problem, said the issue was the thermostat. Luckily I was skeptical and looked it up online, came across your video, ordered the part (Supply House found the updated version I needed) and fixed the boiler in 5 minutes. You are awesome.

[@fixitwithzim]

Excellent, glad I could help!

[@charlesmodrich513]

Had same issue with my boiler running when no heat was called for. Replaced spdt relay and problem solved. Thanks for the great tip. I’m sure I saved a bunch of cash. Note: replacement relay was a dpdt, but plugged in and worked with no issues.

[@wyattbiker]

Good video. Worked for me. Thanks. Boiler ignored thermostat and kept on boiling. Swapped out the relay as per your video and now back to normal. Couple of caveats: The relay pictured on amazon has extra prongs (same one i bought from local supply warehouse) . Still the relay should fit, unless you find the middle two don't have slots. Then you can cut them off. Also make sure you do not unplug other wires by accident. I did that and took me few minutes to figure out why it wasn't working. P.S. Part cost $25

[@khenryb]

Amazing video. Ordered the part today and getting it tomorrow. This saved me so much time troubleshooting and money. Thank you so much!!

[@fixitwithzim]

Thank you!! And thats great that you saved some money. That’s what it’s all about! Good luck with the repair!

[@mlettera]

Thanks for posting. I moved into my place 11 years ago and always felt that our WM gas boiler would take too long to shut off after I lowered the thermostat. I wasn't sure if it was the thermostat or the boiler. Your video gets me thinking it's the relay.

[@fixitwithzim]

mlettera Excellent, hope it fixes your problem. Thanks for the comment!

[@admassudesta6860]

Thank you ,and my question I had one the same to show me, what is yearly maintenance part of this furnace, I can not see gasket and filter. Just I used this year.

[@mgpvii]

Thanks for the video. Just bought the relay for my parent's house. The house just got up to 82 deg because boiler wouldn't turn off. I know the thermostat isn't the problem because I recently changed it assuming that was the problem. The weird thing about it is that it doesn't happen all the time. When I first diagnosed it, everything was working fine but I was told that it happens every once in a while so that is why I figured let me just change the thermostat to play it safe...well, that didn't fix the problem. I now hope the relay is the problem.

[@kjellstrand7]

Thank you! You helped me figure out what's going on, and I'm going to try the repair. Would you come to Brooklyn for a furnace replacement? I am so grateful.

[@buckmikebuckalew4370]

Thanks, good info. I have,, kinda,, similar issue. My boiler kicks on when thermostat calls for heat. But doesn't kick off/shut down when set temperature is reached. Just keeps going. I have to turn off heat. Then when room [or wife] gets cold I have to turn heat back on. Sometimes works like suppose to, sometimes not. Is it my thermostat? Wire from thermostat to boiler?

[@arthurfricchione8119]

Wow where about on Long Island. I’m in East patchogue and do most of my own work. I’m a retired aircraft mechanic. I have a service contract but things are getting expensive so Im learning the system on my own. Anyway new subscriber and enjoying your videos. Very helpful. Happy New Year Artie 👍👍👍 one more thing where is the supply warehouse. Always looking for a good plumbing supply warehouse. Sometimes can’t get crap in the big box stores. Thank you.

[@georgekuntz6864]

I have to tell you... I have had the HVAC company out several times when the boiler would continue to heat beyond the thermostat setting. Even after disconnecting the thermostat, it continues to run. The tech first analyzed it as a short in the wire to the thermostat. After that was eliminated, he said it was a low water sensor, since he could get the burner off when he pressed the test button. $200 for that service call since the part had to be picked up, and it was after 6 pm. The next day he called and said it would be $700 parts and labor since the boiler would have to be drained below the water sensor. Hmmmm... I told them I'd get back to them. That's when I came across your video! I hit the relay, and the burner turned off! I went to the supply house, spent $25. It works like a charm. I figured I spent, or would have spent, over $1,000 with the HVAC company to get the boiler running. I called the company and expressed my displeasure. But it was tempered by the overwhelming joy of fixing something for $25 vs being taken for $700. Thank you so much!

[@fixitwithzim]

George Kuntz Glad to hear you got it resolved with the help of the video. I went through a similar process. I had a HomeServe contract for that "just in case" moment if the boiler happened to go down while the wife and kids were home and I was at work. What a complete waste of money. Had them out several times. They told me everything was operating normally. They couldn't have been more wrong! I have long since abandoned service contracts and learned that I'm the only one I can trust working on my house. Again, thanks for the comment!

[@sundown798]

George Kuntz Good for you. Tons of support all over the internet. These systems aren't that complicated. Like working on a old Ford pickup vs systems like lochinvar ect uber high advanced computer controlled stuff like trying to reverse engineer a UFO haha. I prefer simple engineering.

[@manjolanika3786]

zimsjeep would this work the same for oil boiler ? I have a similar issue. Please let me know. Thanks

[@ptyptypty3]

WOW, your video explained everything that was acting up with my Weil McLain CG 6 series 11 !!! I can't wait to try that!! You showed how Simple it was!!.. THANK YOU THANK YOU THANK YOU... I am a new subscriber and your videos are Perfect for my System!!!..

[@fixitwithzim]

Great to hear! Good luck with the repair!

[@ptyptypty3]

@@fixitwithzim Sure Enough .. replacing that Relay FIXED THE PROBLEM... for the last two winters I've had to go downstairs, turn the Main Power on to the Furnace, then let it run for awhile.. then go back downstairs to turn the power off.. TWO YEARS... but replacing that Relay fixed it !!.. Thanks to your video!.. you do a great service. I think I'll take your advice and go buy a Six Pack of Beer with the money I saved!!.. lol... See ya.

[@ktsang47]

I have the same issue. But when I tap on the relay it doesn’t shut off the boiler. I am still going to replace it and see if it will fix it. But does the tap the relay trick always work? Can’t get a relay for a week special order here in Canada.

[@kellymorton544]

How do you plug it in? My old one had 4 prongs and the replacement has 10 prongs

[@revbikerbigd8664]

Thanks so much for this video. My HE-3 inducer motor stayed on, got part local plumbing parts house for $27.00 mine was updated from part# 91-322000-11000 to Universal #510330223 which has extra spades on it, but doesn't matter they said. plugged it in and works great now! Many thanks! Clip was hard to get back on! My electric bill when up $30 because it ran many times longer than it should have when we were not off! (Transformer and Relay, 120/24V part #510-312-167 Brand Weil Mclain ,Whole unit if needed)

[@fixitwithzim]

You're welcome, glad you got it fixed!

[@Soprano0913]

Great video. I have pretty much the same boiler is known as a Williamson Thermoflo GWA-105-N-S . The issue in using is my circulating pump is continually running. Please help

[@richardhardy5927]

This was a great video, made the job very easy and you were right, the part only costed $23. Saved me so much money!

[@fixitwithzim]

Richard Hardy awesome, glad you got it fixed. Thanks for the comment!

[@joep4143]

No such word as costed

[@FeralFlatts]

Any chance you have a video on replacing the burners?

[@seiji64]

This exact issue happened to us last night with our W-M boiler. Tapping the relay turned off the boiler as you described. Thank you!

[@fixitwithzim]

+Seiji G Great, glad you found the video helpful. Replace that relay because it will most certainly get hung up again.

[@KS-cu1zc]

Hi there same boiler kicking on & off continuously ,any help there ,any heat sensor on these could be faulty ,if I increase thermostat heat on one or more then it will fire up thx

[@justinfoesch3736]

The huming noise the heater makes right before it fires on the one I have is getting louder is that the transformer going bad?

[@peteyolles]

thanks for taking the time to share the knowledge...

[@rickc9873]

I had a high limit failure. The boiler wasn’t shutting off at all relief valve blew off Bought the relay also just in case. Excellent video !

[@fixitwithzim]

Thank you! Hope you got everything fixed!

[@djva89able]

What I need to do after the pilot it’s in? Because the other flames do not work “doesn’t have flames in it”

[@williambell4591]

Absolutely AMAZING, I have the exact same boiler - I kinda felt it was a "relay" or something that was sticking - I gently knocked that front piece w/my flashlight, and sure enough, the boiler turned off! I was going to perhaps attempt spraying some WD40 on it, but I found this video! Thank you so much, absolutely amazing this is the exact issue! THIS is what KZbin is for, and all about! Edit (at end of video) YEP, I agree - I felt the same way, $200+ service, for an inexpensive part - that why I was going to attempt to "WD40" 'it LOL!!

[@fixitwithzim]

Great. I know the exact feeling when you find a video that solves the exact issue you have. It’s almost like finding the video is better then the fix!

[@LuisCruz-qn8qt]

I have problem,when I put my thermostat in auto shutoff but when I switched to on is fired up. Any idea?

[@tsrehman]

I would like to put a new gas water boiler at my house It is 6 bedroom house 2000sqt build up area Which boiker Will you recommend Nd brand with series number Thank you buddy

[@sulochanagosalia8455]

Can you please educate me how to replace flame Sencer o Weil McLain PCs-5-f1 Thanks

[@trikerjon]

Thanks you solved my problem and saved me money 👍

[@michaellovetere8033]

I've got an old weil-McClain doing the same thing. Thanks for the tip...

[@josecanales3702]

If the boiler is working fine with the Thermostat, but the water is getting up to 220 that mean is the limit control the bad one? And what kind should I buy? Thanks

[@c.cortes1888]

You are the man! Thank you for posting!

[@matthewtyson9367]

How do you light pilot on boiler?

[@thomasbroking7943]

i was working during that time.. super hard time getting gas switch plates.. i was buying blank plates and spray painting them red 6 at a time, just to have something. i wish we had that supply house back then. our warehouse manager would have to make tons of calls to locate parts never saw that part.. they only had the whole combo and i believe the price book had it for 585 installed that included the diagnosis then getting and installing the part. if it's winter i had to go get it and return.

[@fixitwithzim]

Interesting, that would problem explain why the wrong plate was installed…thanks!

[@briancarney3035]

After I replaced relay the pilot light went out. Now it won’t light again. Any ideas?

[@robinahmed3778]

My one is small fire I see always on but I do on the thermostat it remains same not work.

[@mattieice2988]

You my friend are Awesome just did exactly that and boom works perfect

[@mikepier1]

Nice video. good to know about the relay operation.

[@fixitwithzim]

+Mike Pier Thanks. I've had 2 houses with same system and the same issue. Makes you wonder how many more are out there like that. An unsuspecting homeowner with little knowledge of their system could be wasting a ton of fuel.

[@joallynhenry6142]

zimsjeep, I learned alot. I alsofound supply house. need to replace aquastat on weil mclain CgA series 2 at least 40 years old. can u suggest video or website?

[@fixitwithzim]

Jo Allyn Henry Sorry for the delayed response. Check out Steven Lavimoniere Plumbing on KZbin. He has a ton of boiler videos that would probably help

[@CPRebels21]

You can also use resideo R8222D1014. More likely to be stocked at your local supply house.

[@Static2606]

You mentioned yours has a vent damper on it. do you have a wiring diagram for that? Mine has the standing pilot with no damper and I would really like to upgrade it.

[@fixitwithzim]

Do you still need this? If so I will put something together. Sorry for the late reply

[@dohar9]

Great video, very easy to follow. I have a Weil Mclain CGM-5-P1 series 8 boiler. From what I understand this relay controls the turning the boiler on and off. My problem is that sometimes when the boiler is starting up it makes a clicking/chattering noise (not the normal click click click from when the pilot is igniting) the pilot lights, the burners flame on then off then on. The whole time the chattering continues. Could this relay being bad cause this to happen intermittently? Could the relay be hanging up?

[@fixitwithzim]

It could be but not likely. Pull the cover off and try to pinpoint where its coming from and report back. I'll try to help you.

[@nildamendez2645]

Where can I buy a new boiler to replace my old residencial McLain boiler.

[@VegasTD1]

My unit stops heating but the fan keeps running. Then i have to reset the power and then it runs sgain for about 1 hour snd shuts down again. Any idea what is causing this?

[@josephmiller8938]

I have a whale McLean cast iron water board furnace and I have some water in the air tank that's beside that for the pressure and also my furnace my pilot light stays on but my formless lights up and just stays lit for just about 3 or 4 minutes at the most and goes right back out but the pilot keeps burning can you tell me what my problem is

[@fixitwithzim]

Sounds like one of the safety switches is turning off the gas valve. Start bypassing to see which one is causing the problem then fix whatever it is

[@blcksteam]

Wow man thanks!!!!!! for the video i think my Mclain is doing the same thing.

[@00tonytone]

I have a honeywell circuit box. The relay switch stays on with a buzzing noise and flame shuts off when the pipes are real hot. Any idea what it could be. I bled the line of air. Still does it. Thank you.

[@fixitwithzim]

You’re going out on safety. Could be a number of things…start with the easy stuff. Roll out sensors, etc

[@davejones2338]

Nice video, thanks for posting. The pilot will stay lit during this repair?

[@fixitwithzim]

Thanks, yes pilot will stay lit. No need to shut the gas off for this job.

[@manouneideh]

Very useful video.

[@McClatchey14th]

Great Vid!!.. I hope this will fix my issue, My WM boiler runs for at least 20+ mins. after the temp is reached at the T-stat. I'm using a Nest T-stat and everything worked great for the last 2 years, now i'm getting drips from the relief valve because its building up close to 30lb of pressure, because it is staying on longer then (what I think) is to long. I emptied the expansion tank, and that helped. My main zone goes over about 3 decries before shutting off..... ya think this is whats going on, bad relay?? THANKS for your response-s.

[@fixitwithzim]

Do you have a cold start boiler like the one in the video or do you use your for domestic hot water as well?

[@timothyschumacher7063]

Nailed it, funny that I did the same thing with the screwdriver and that's how I found the problem. Thanks for the info

[@fixitwithzim]

Thank you, luckily an easy fix.

[@mikepier1]

I manage 2 buildings with Weil-McLain steam boilers ( see one in my videos). It comes with a relay option if I ever wanted to hook up a separate hot-water fed zone. Best thing I ever did to save money and time was hook up Wi-fi Tstats in each bldg so I can monitor the heat from my smartphone. If a tenant ever calls saying it's too cold, I can raise the Tstat while I'm sitting in bed. On warm days, I shut it down

[@samet3504]

Well matten

[@WunderboyStudios]

Thank you for that video! My Weil McLain boiler makes a kettling noise when it heats up. Anyway to fix that?

[@fixitwithzim]

Wunderboy You're welcome. Sounds like you have air in your system. Bleed it out at the circulator purge valves.

[@WunderboyStudios]

zimsjeep ok, thanks!

[@kellymorton544]

Was your boiler short cycling? Turning on and off?

[@mrbigcat9]

Do you shut off your boiler pilot light, by shutting the gas valve to the off position, during the summer months?

[@fixitwithzim]

No, pilot stays on. I never shut off the gas valve

[@aminulislam-eq4mv]

Nice video and good explanation. I have the same type of furnace Weil McLain. I have two zone valve, one on the first floor and second one in 2nd floor. When I turn thermostat on the first floor its work, but when I turn on second floor thermostat it doesn’t work machine will turn on but doesn’t see the flame 🔥. What could be the problem, please help. Thank you

[@fixitwithzim]

Does the pump come on?

[@aminulislam-eq4mv]

@@fixitwithzim yes pump is on( inducer fan running constantly)

[@jerryrutherford5283]

Can a bad relay also cause chattering on start up. I have 3 zones. 2 of them start fine just a click, the third one there is a little chattering noise before it starts. Other wise stays running and shuts down when it should.

[@fixitwithzim]

Yes, probably a bad switching relay. Easy to change

[@FelixV]

I have an issue with my CG-4-SPDN. i just bought the house over the summer and it's my first turn on the thermostat. When the Thermostat turn to 80 nothing happen. I checked the boiler the pilot was lit but that's it. Where do I start to troubleshoot. The Mclain I have doesn't have the power switch as I seen on your video and I found no switch near by. Any information you can provide is great appreciate. Thank you

[@fixitwithzim]

There should be a service switch somewhere or emergency shut off switch near the door or stairs if in a basement. You can check for 120v if your comfortable with electric at the j box feeding the boiler. That's your first place to start. If you have power, the boiler could be out on safety or the thermocouple could be faulty. One other thing to check that's pretty easy to spot is chimney damper motor. Is it opening when the boiler calls? If the motor isn't working and opening the damper, it will lock the boiler out.

[@FelixV]

thanks for response. i see no emergency shut off switch near by or on the stair. I'll start with the electrical box and shut off the main breaker box. I'll try to replace the thermocouple and see what happen.

[@theeman122]

I have the same unit, but mine only has the pilot on and circulation pump runs but no heat. Was working last winter. Any suggestions?

[@fixitwithzim]

Possible causes: locked out on safety from a tripped sensor, vent damper not opening, bad gas valve. Check the vent damper first. A lot of times they’ll get stuck in the closed position after sitting for the summer months and not being used. This will lock the boiler out from firing.

[@kimberlyebrani1562]

Thanks it was useful, but can you show me how to turn on the pilot as well in the same model?

[@fixitwithzim]

You’re welcome. Maybe I’ll make a video sometime soon on how to do that

[@tommycastellano7226]

Hey I have a Weil McLain boiler. My pilot is lit, but is not turning on boiler. Any ideas?

[@fixitwithzim]

+Tommy Castellano Bad thermostat? Start with the easiest possibility and work your way up.

[@rairdanrealty]

Thanks so much for this video - saved me $$. If you unstick the relay by tapping it, will it possibly return to normal operation? Does running your boiler hot (190-200) increase the possibility that the relay will stick? Thanks!

[@fixitwithzim]

It will return to normal operation but not for very long. Eventually it will get stuck again. I would look to replace.

[@georgekuntz6864]

One other thing... the low water sensor won't shut off the burner, when the relay is stuck in the on position. At least in my case. Which is why the tech assumed it was a bad low water sensor.

[@ptyptypty3]

Hi Zim ... I replaced my Relay in October of 2019 .. it worked MOST of the time... maybe only 7 times did it not work... but I decided to buy a NEW Relay, at SupplyHouse, and it arrived today, October 28th, 2020. but it doesn't seem to turn the heat off when it should... So, Has your Furnace been running fine since you replaced your relay?.. by the way, I have the Identical Furnace that you have... a Weil Mclain .. Identical!!.. so, any feed back would be great... I may have to check the wire connections to the Transformer... thanks for the video...

[@fixitwithzim]

Hey there, interesting. I haven’t had any problems with the relay I installed in the video, believe it’s around 5-6 years old now. Check to make sure all the terminals are nested properly into the board. Also like you mentioned, check your transformer voltage. Just eliminating all possibilities here...pilot on? Also make sure your chimney flue damper isn’t stuck closed.

[@ptyptypty3]

@@fixitwithzim wow Thanks Zim for responding!!. I did Notice that your video was done in 2015... that made me wonder if your Relay was still working... It's been working 95% of the time... but when it's not I turn off the Power to the Furnace... and then tap on the relay... But I did buy a new one.. and it did not work at first,,, but I waited a day and now it seems to work .. anyway, THANK YOU for responding.. glad your relay works fine all these years.. :)

[@jgg5407]

Thank you for helping people and my

[@fixitwithzim]

You’re welcome!

[@maxgrind438]

Interesting . Did not need it but good to know. Thank you

[@fixitwithzim]

You’re welcome, thank you!

[@lxc1227]

I unnecessarily replaced the transformer-relay kit ($70) and all I needed is the just transformer you paid $18. I got my parts from SupplyHouse too. Wish I see your video first.

[@gunit6815]

So I have Weil McLain Model CG boiler in my house. It cycles on and off all day to maintain temperature even when the thermostat is off as well. I would love to know if I have the same problem in mine. We have been having some large gas bills last winter (we just bought this house, our first home) here in Canada, and now we have had carbon tax for awhile now so that doesn't help the heating costs. My boiler is on a tekmar house control 370 computer and the boiler heats a fan coil which inturn has hot air blow over it to heat the house with forced air so the coil acts like a heat exchanger in a traditional forced air furnace. Also have in floor heating in the basement. Boiler is not making hot water as well in our home. Dedicated electric tank. Not sure if its similar to your setup. I too would love it if my boiler only turned on when the fan coil demanded heat. Would this also fix my issue? Currently we just kill the power via switch to the boiler when heat isn't needed or in the summer its always off as the fan coil also has central AC in it. Looking to save on my gas bill here in Canada, as every year the carbon tax keeps going up up and up costing more each winter for heat.

[@fixitwithzim]

Hey man, definitely sounds like your set up should be a cold start system. Do you have a relay similar to the one I showed in the video?

[@gunit6815]

@@fixitwithzim Yes I do. And I cannot seem to find it anywhere. The relay in the boiler says W-R/RBM 91-112006-11000 Coil 24V 50/60HZ

[@evaristovasquez2967]

I watch your Video my boiler keeps running with thermostat off i purchase the relay you suggested # 510350223 from Supply house install it but Boiler still keeps running what else could be the problem.

[@chayotito09]

Hi and thank you for the video. I think I have the same problem but even if I tap the relay the furnace doesn't shut off. when you say I shot off the thermostat are you lowering the temperatures or turning the thermostat off? My problem is as soon as I turn the thermostat to heat the furnace turns on, the circulator never shuts off and the furnace keeps 180 but keeps going even if it's not calling for heat. the only way to stop it is switching the thermostat off. Thanks in advance. I ordered the part but was sent the wrong one.

[@fixitwithzim]

Juan Carreon With a cold start boiler, turning the stat off or lowering below the set point should have the same effect...boiler will not fire and circulators will be off. In my case with the relay being bad, when the stat was off or not calling, the circulator would be off but the boiler would maintain high water temp. Is the tstat wired correctly or has it been changed recently?

[@chayotito09]

zimsjeep Hey thank you for taking the time on the video and answering my questions. We bought the house over the summer and I installed the thermostat because it was missing. The problem was on the thermostat wiring. Wires were not marked. I figured it out last night and we slept nice and toasty. I really appreciate your help.

[@fixitwithzim]

Juan Carreon Great, glad you got it figured out!

[@chayotito09]

zimsjeep Thanks for your help. without this video I would not have known where to start.

[@JB-ez2xv]

Can you explain from A to Z how this type of boiler works? There actually isn’t a single video on u-tube that remotely does this. Please explain the relationship between the low water cutoff, the automatic feeder pressure cut-off and the wiring that allows these to communicate with each other Thanks

[@fixitwithzim]

Jayson Bastien That would be the subject for another video. Essentially most boiler control circuitry is wired in series so that if any one of the safety devices trip, the boiler will shut down. The water feed is just a pressure switch, no relation to the low voltage controls.

[@MikeCaskey]

What do you think would cause a boiler to constantly heat one zone, even with the thermostat disconnected, when it doesn't appear to have this kind of relay?

[@fixitwithzim]

Mike Caskey Could be a few things. Bad switching relay, bad wiring from tstat to relay, no flow check valve installed? Disconnect the tstat wiring at the boiler relay and see if it shuts the pump off.

[@MikeCaskey]

Thanks, will do!

[@evezford]

I followed the advice and replaced relay on my dual unit(baseboard heat/ hot water) . It’s still heating constantly. What should I change next?

[@fixitwithzim]

Disconnect the thermostat wiring and see if the unit shuts down and stays off. If yes, then tstat or wiring to tstat is your issue

[@evezford]

@@fixitwithzim Thank you for your reply! I removed the thermostat, it kept running. I even disconnected the red and white wires in back and let them wave in the breeze. This has no effect, the heat still blazes. I just shut the power off when I’m warm, turn it on when cold. By now I’m guessing it’s time to call the professionals?

[@gyver471]

Mine the flames are really high any thoughts on that?

[@fixitwithzim]

Gas pressure maybe too high. I don’t recommend touching or working on anything related to the gas supply yourself. Call in a professional.

[@rawbasicrawbasic]

thanks for sharing this video I'm having the same problem

[@fixitwithzim]

rawbasic rawbasic You're welcome! Thanks for the comment

[@amindiy7001]

Hi not sure if you still running this boiler but I will like to see how your vent damper is wired up, I have the same boiler and wanted to add flue damper. Will really be appreciated. Thanks

[@fixitwithzim]

I’ll make a quick video this weekend and upload. Give me a couple days

[@fixitwithzim]

I posted a video on the vent damper wiring, hope this helps you. kzbin.info/www/bejne/maDNlKCNd9SredE

[@manouneideh]

Gave it a thump up and subscribed.

[@fixitwithzim]

Thank you!

[@manouneideh]

Hi. The rely my unit has is the same as you showed but when I tried ordering it from the company you recommended they display a different piece. Mine has only six plugs and theirs with ten. Advise please.

[@manouneideh]

*relay

[@fixitwithzim]

killy brown The part number in my video is exactly what you need. Sometimes the pics are wrong on websites or a generic pic of a similar part

[@manouneideh]

Thank you again.

[@claudiamarieclappsy8137]

Excellent, I will let my hubby know.

[@fixitwithzim]

Excellent...good luck!

[@HHOGAS]

You need to upgrade your pump. If your pump is similar to what I have the same boiler system your pump is moving 35 gallons a minute at 8 psi. You need to add that extra hot water tank as a helper and as a storage tank also. You also need to turn down the burners by 50% and the 3 individual pilot lights need to be turned out also to save on gas also. My system has been running with this concept for eight years saving on natural gas. The installation date Nov 2, 2013 I have been using my 50+-year-old hot water boiler system for over 8 years using 50% less natural gas to heat the hot water to heat the home that has cast iron radiators. When I first purchased the house, it had a pump moving water at 35 gallons per minute at 8 PSI. Today and for the last six years, the pump that was replaced back then is now moving water at 45 gallons per minute at 45 psi. Boiler specialists that went to college to be taught box education disagree with my concept that does work. Heating and cooling individuals are totally wrong in their understanding of using fire efficiently. Let me explain it in an elementary way. On a natural gas stovetop if you turn the flame on high and the flame wraps around the pan and the flame is blazing into the air and not heating the pan you are wasting natural gas or propane gas to fire. The next thing they will tell me it will take longer to heat the pan. Wrong again if you take that same amount of water and you put it in a larger diameter pan with the same amount of water and spread the flames out equally across the larger surface you are capturing the fire that is heating the pan that is the heat exchanger that will heat the water faster. In my boiler system, the three small pilot lights for the boiler were turned down and the 8 large burner jets in the cast-iron boiler were turned down allowing the flame to heat the cast iron 50-year-old plus boiler system heating the water instead of heating the air going out the chimney. Once you achieve that savings by turning down the boiler system you need to add a hot water tank to heat water on the input side of the boiler as a reserve that when the water returns from the house some of it goes through the hot water tank and the rest of the water continues to the boiler as is. When the water is returning, and it is close to the hot water tank and the boiler some of it goes to the boiler and some of it goes to the hot water tank that is plumbed into the return pump that blends the return water from the house and the hot water from the hot water tank on the input side of the pump. Once they blend the returning water from the house and the water that went through the hot water tank then it goes into the actual boiler and gets reheated again and speeds through the plumbing to all the cast iron radiators in the home 45 gallons a minute at 45 psi. You have to know how to adjust the hot water helper tank according to the outside temperature so it does not come on every time the boiler comes on the heat the water in the house because you are defeating the purpose because now you would be using two flames reducing the energy efficiency that you are trying to save. When the temperature outside is over 35°F the hot water tank needs to run below the hot water hot temperature setting that says hot water. When the temperature outside is 15°F to 30°F then you will raise the hot water tank temperature to the hot water setting marked hot water. You have to stand next to the hot water tank during the cycle period to make sure the hot water tank is not running continuously when you are using the hot water tank as a helper. The warmer the temperature is outside the cooler the return water will be traveling back to the heat source to be heated allowing you to turn down the hot water tank, so it does not come on when the return water is returning and some of it is going in the hot water tank as the helper. The helper hot water tank is not to be used as your main hot water source. Once you master your hot water tank to the outside temperature and the return water temperature from the home you will be using only your boiler system gas that was turned down by 50% for your savings of heating the home or business. Let me emphasize again the warmer the temperature is outside the cooler you run your hot water helper tank. The cooler it is outside the warmer you run your hot water tank because the return water will be returning to the tank on the return side much hotter matching your hot water tank setting on the hot water tank. Once you do it for the first time and you measure your return hot water temperature you will fully understand that hot water is a hot water energy bank of energy stored to help heat the home and for assisting the boiler. When it comes to a forced-air furnace that will be in a new description later that I will show how to work that system with the exhaust gas motor fan speed and the amount of natural gas being used in the heat exchanger and the speed of the home circulation fan all working together differently from what the manufacturer requires. Remember everything was designed to use more fuel than what is needed due to the flame size, heat exchanger size, and moving the heat with the circulation fan. ****My system set up**** Nov 2, 2013 We just Made public the 2 videos again of the installation date of the 45 gallons per minute and 45 psi pump setup boiler system set up flow rate of natural gas being used. kzbin.info/www/bejne/Y2eyiZqip56psLs Showing the reduction of Natural gas flow on the boiler system. kzbin.info/www/bejne/Zpi1n4evnqhgnZI --------------------------------------------------------------------- This link is someone converting their forced air furnace into a forced-air hot water heating system. kzbin.info/www/bejne/g2e4lWRjiK17gZI This link will reaffirm my concept is not fantasy but fact. kzbin.info... Second link www.google.com/search?q=hot+water+forced+air+furnace&sxsrf=AOaemvJ0QgkYgolZLAH4wtX53JOv8TlkOw:1641528593453&source=lnms&tbm=vid&sa=X&sqi=2&ved=2ahUKEwiSy83F4p71AhVL6RoKHRi1CnEQ_AUoA3oECAIQBQ&biw=1529&bih=511&dpr=2.25

[@fixitwithzim]

Interesting take, I’ll take a look at your system. Thanks for sharing

[@aleung1946]

You are the best I love you

[@daveaj584]

hi i have the same boiler but the problem i am have is that the i set the termostat at 80 and the room temp is at 60 but the after 8 hours the room temp on go up 2 degree the most the boiler come on for about 2 min and shut of need some help please

[@eitanchakov]

Check your zone valve or your circulator

[@daveaj584]

+Eitan Chakov. do u have a email i could send u some pic

[@smoovlatino]

I’m having an issue that maybe you can help with? Same furnace, same parts - the gas valve will not actuate despite the thermostat calling for heat. I tested the R and W wires at the TSTAT and the control board with a good 24V. I tested the lead from the control board (transformer) to the gas valve = 0 volts. Should I replace the entire control board or just the relay? Any idea what may be the issue?

[@fixitwithzim]

smoovlatino Power to the gas valve is wired in series through all the safety and control devices. Could be a couple things. Bad rollout switch, flue damper motor not opening, bad limit switch, etc. You lose one or more of these, it's breaks 24 volts to the gas valve preventing the boiler from firing. Get an ohm meter and ohm out each device. You'll need to isolate each device to test them. Hope this helps

[@smoovlatino]

zimsjeep checked continuity... relay good and transformer good. Culprit was the thermal cutoff circuit breaking the 24V. Flame rollout was triggering the 228 degrees C to burn out the safety circuit. Jumpered the circuit, cleaned out the soot, and lowered the gas output to a consistent 128 degrees at the circuit.

[@johnrebelo6688]

How do I set my water temperature to reach 180f? It’s always around 140f I have a weil mclain gold cga boil. Any help is much appreciated thanks

[@fixitwithzim]

John Rebelo separate hot water heater or do you use your boiler for hot water heat and domestic?

[@johnrebelo6688]

zimsjeep It’s separate I have a hot water tank for my water And a hydronic baseboard water heater for my heat. Similar to what you have

[@fixitwithzim]

Does the hot water tank use a zone on the boiler or is it a separate gas fired unit?

[@johnrebelo6688]

zimsjeep it’s Separate gas unit

[@asmith5799]

I have this too, did you get an answer? Same issue for my 4 zone boiler. Changing the economy adjust and boiler temp dials made no difference. It runs 1.5 mins then shuts off. 6 mins later it's back on again and repeats. That LED light never moves past 140. Any ideas anyone??

[@stevenramsar456]

Thanks brother ❤❤❤❤❤

[@lxc1227]

Wished I saw your video before hand. I bought the relay/control center for $60 or $70 from Supplyhouse.com. Only the relay was faulty.

[@fixitwithzim]

Well, at least it fixed! Thanks for the comment!

[@alal9455]

What if does not fire any gas

[@rickw4160]

love supply house. but just wanted to say that they are hardly local to long island. More like local to Upstate NY, (and apparently Cranberry NJ just recently)

[@fixitwithzim]

Around the time I filmed this video, they were a local company on Long Island. They’ve since expanded and grown. Thanks for the comment

[@rickw4160]

wait, they have a location in Long island???? I honestly didn't even know, I thought they were only upstate..... I guess I can make my returns in person!

[@ErinDClapper]

Hi!! I am having the exact opposite problem and I'm wondering if you have any ideas. My thermostat reads the accurate temperature, and has a temperature programmed, but more than half the time it doesn't kick-on the boiler. There's a call for heat and sometimes it will work on its own, but I've come home to a house at 49 degrees many many times. I can usually force it on by manually flipping the switch but I'll have to do it a few times. Could this relay cause the opposite problem too? Thanks!!

[@fixitwithzim]

Could be this relay but could also be out on safety and when you turn off and on, it's resetting something. Some model boiler?

[@shawnlyon5431]

I have a boiler in my home same brand but I no power from the switch to the boiler but I have power coming in hasn't tun since I lost power

[@fixitwithzim]

Shawn Lyon Do you have another service switch somewhere for the system? Most have 2...one near the boiler for the tech to use and another location for emergencies. One other possibility is the switch went bad. Hope this helps.

[@shawnlyon5431]

the thing is I have power coming in to the unit but no power from the switch to the boiler

[@ThanhTran-br9yh]

Thanks for the tip.!!!

[@fixitwithzim]

No problem, thank you!

[@timothymaurer6720]

My boiler won't shut off when I teach my desired temperature. If I tap on the relay, it will shut off and the flue will close. If I replace the relay (90340), the flue will open but doesn't stop opening when it should (dors a full cycle) and the boiler/gas will not start. If I put the old relay back in, the flue will open, stop and the boiler gas will ignite. It just won't shut off again. What is the issue?

[@nikosniko7092]

Maybe check the sensors ?

[@mUser21m]

clean that boiler while your there....flame looking a little iffy?

[@EdSilCarNatfam]

Just bought a house with one of these bad boys. I was looking to see if I can replace the 2 wire thermostat with a smart one and came across this. Good reference though if I need in the future.

[@fixitwithzim]

Yes, you can definitely add a smart tstat. Do you have 3 wire running to the thermostat location? If so, just connect the common to your transformer for power

[@josephmiller8938]

The pilot on but furnished won't a guy I'm sorry furnace and nice but goes out very quickly what's my problem

[@fixitwithzim]

Tripping out on safety. Maybe flame rollout? Do you have a vent damper? Start with the easy stuff

[@Randijo1111]

I replaced that relay on my Weil Mclain boiler but it didn't correct the problem. Does anyone have any suggestions as to what my next move should be? I saw another video where a guy relaced a vacuum line, but I don't see any visible lines on my unit. Thanks...

[@fixitwithzim]

Randi Jo What problem are you having?

[@Randijo1111]

The boiler is cycling every 5 minutes. It'll run for 1 minute, then off for 5 minutes. I replaced the relay that you showed in your video but that didn't fix the problem. It has 3 zones and I completely disconnected the Taco zone valves, as well as the thermostats, and the problem still exists. I had a boiler guy come by yesterday and he couldn't figure it out, either. He called me later in the day and said he wants to replace the 24v transformer that sits right next to the relay. I'm not sure how that could be the problem. And the part of this that completely confuses me is that the cycling is like clockwork - down to the second. What can be setting this off???

[@fixitwithzim]

Randi Jo hmm, do you have all the controls disconnected? Maybe a bad aquastat?

[@Randijo1111]

All thermostats were removed from the wall & the zone valves were removed. So the problem is definitely within the boiler. Having already replaced the relay, the only thing left is the 24V transformer next to the relay, correct? Looking forward to hearing back from you.

[@fixitwithzim]

Randi Jo same boiler as the video? Do you have a domestic water heater plumbed off a circ zone or is it separate?

[@philthemonstercujo2034]

great video

[@fixitwithzim]

Phil the monster cujo Thank you!

[@kevin17111]

Right on the point

[@taiwancunningham6027]

if the relay is bad. what did cause the heater to run for 4 minutes and then shut off. even if the heaters not reaching its set point

[@fixitwithzim]

+Taiwan Cunningham Once satisfied, the thermostat breaks the connection shutting the boiler off. The relay was allowing the boiler to maintain temp even with the stat not calling.

[@taiwancunningham6027]

+zimsjeep ok. my heart runs for 4mins and then shuts off and it won't go over 60 degrees even with the thermostat turned all the way up

[@fixitwithzim]

+Taiwan Cunningham Sounds like the boiler is reaching temperature and shutting down which is normal. How cold is it outside? Is it unusually cold out? Do you have baseboard hot water heat?

[@taiwancunningham6027]

Its like 20 degrees outside. It's 60 degrees inside the house if you turn the thermostat to 70 the heater runs for four minutes and it shuts down for like 5 minutes then he runs for 4 minutes again and shuts down it never reaches 70 degrees and I jumped out the thermostat and still does the same thing

[@fixitwithzim]

+Taiwan Cunningham That's how the boiler should be working. It will heat the water up to around 180-190 and shut off when it reaches that temperature. When the water returns and has cooled, the boiler will refire and hear it back up to 180 again. Maybe you have air in your system? That could affect efficiency. Do you have separate central air vents? A problem I had in the past is the warm air escaping through the ac return grate. Blocked that up with some foam and was good to go.