Pentair Master Temp 400 Pool and Spa Heater HLS Error Light Repair Replace Manifold Bypass Valve

Pentair Master Temp 400 - got an HLS error light on the back of the gel touch circuit board of the heater control panel. This video shows the removal and disassembly of the Sta-Rite manifold attached to the side of the boiler. I ended up replacing the Manifold Bypass Valve instead of the suspected HLS (High Limit Switch) to clear the error.
Part number of Manifold Bypass Valve is 42001-0014
Part number of the HLS (High Limit Switch) is 42001-0063

[@stevemclaughlin4713]

Awesome video and great instruction on the replacement of the internal bypass valve which cause the heater to cycle on/off every 30-60 seconds and shows up as an HLS fault. I bought the manual bypass, new o-ring kit and the HLS (just in case - it was only $14 on Amazon) so for $54 I have a perfectly functional pool heater!

[@RDBrown73]

A great help. I had the same problem, but no rattling. My valve was stuck in place. Lucky I guess. I replaced the HLS and the AGS as the manual suggested. Then as I was about to replace the thermal regulator, I found the valve sitting on top of the spring of the thermal regulator assy. Now I know an easy way to check it is to pull the thermal regulator plug and see if the valve is in place above it. I found your video and was kicking myself for not watching it sooner. I wasted over $100 dollars on parts! Also, I think the manual actually calls it a manifold bypass valve. Thank you!

[@robbythecuban]

Oh my God, you’re my savior. You even read off the part number!! I wish that everyone’s “how to” videos were done this well. Thanks!!

[@natelongfellow7399]

Solved my problem. Looks like a common issue. Took me a while to figure it out, but thanks to your video, totally found the problem and fix. Thanks for taking the time to help. Much appreciated.

[@AquaTech225]

It’s not all that common. I’m actually a warranty Tech/Warranty center for pentair. They do fail. The most common things I see. Since I never get calls from people that their stuff is running good. Only the bad. And I cover pretty much 3/4 of my state and some of one of the states next to me. 95% of the heater issues. Tends to be the high limit, thermoregulator, or the thermistor. Than I get some of the ignition module and even fewer of the control board. 9/10 the sensors is from corrosive water. The board an module just tend to give out sometimes. The internal bypass. I’m not sure how much water chemistry effects the plastic of that or the hot water. But out of years now say 500 heater repairs I may of replaced 8 of them things total. But while it’s running and u hear clunking an clacking it’s a 100% sure sign of that bypass

[@theinternetelectrician]

From the Internet Electrician to you, a heartfelt thanks!!! It was my issue as well! After replacement of HLS, thermistor, and countless hour of trying to figure out what is going on, the nightmare is over! Took it one step further by putting in a small screw and washer to hold the valve stem in place while I wait for the parts. I can’t be without my hot tub for 3 days!

[@koolbreezekilo]

Got my manifold bypass valve in the mail, watched your video and an hour later, my heater is working perfectly. Thank you for the video!

[@pvt-pilot]

Fantastic!

[@charlesbutterfield1933]

This is very informative. I have the identical problem with mine...rattling and HLS light. I am preparing to do this exact fix. I especially appreciate the 13 mm callout. Wish more DIY videos would call out tools and sizes...saves many trips to the garage. Thanks for doing this video.

[@doughboy1338]

Man you saved the day. I couldn't find out where this plastic valve and stem was supposed to go. Thanks!

[@jorgemurrieta5732]

Good one I have the same problem and this video help me fix the heater first time to change a bypass valve. Thank you for showing how to fix it 👍👍👍

[@fzintzun]

This was great. My son and I fixed ours together and we were finally able to use our jacuzzi. I found the broken piece still in the manifold, got lucky I didn’t have to hunt for it. Thank you for the video.

[@pvt-pilot]

Right on! Replies like that are exactly why I posted these videos...makes me smile. Cheers!

[@fzintzun]

@@pvt-pilot seriously it was good to work on this with him. I was so happy when he said I'll help you dad. He's usually online gaming.

[@FrankButry-ee6nb]

Excellent video! Thanks for your help. Unfortunately I’ve only had my heater for less than 2 years and also have to replace thermo regulator. Ordered today and hope to have it up and running tomorrow. Thank you again!

[@MrSpottswood100]

Thank you so much for this video. I had the exact same part broken. You video made this repair very easy. $30 part from Amazon and 1 day shipping. Saved me a fortune!

[@jinboden5228]

Fixed my problem and saved me a fortune. Thanks so much for posting. I did have to cut off the bolts as mine were old and rusted. Bought replacement bolts (stainless) at lowes

[@davidfaler]

Awesome instructional video! I really appreciate you sharing with us. You saved me a lot of time and money. I will order the new part today along with some o-rings. Thanks again

[@chuckkercsmar6648]

Excellent video. I sure wish the troubleshooting guides would have a picture as to where the diagnostic LED's are. I spent a couple of hours trying to find them. I had put in a "Service Heater" warranty call which ended up being misdiagnosed as a gas issue. After spending 2 afternoons with gas company personnel I dug in myself and found the HLS LED was on when the heater burn cycle shut down.

[@prddpm]

I thought for sure that this was my problem. I also have a rattling and then kicking off Mastertemp 400 with the HLS error light. Mine is only 4 years old. Anyhow, I took it apart (thanks to your video), but my bypass valve is fine. Maybe mine really is the HLS sensor. But then I don’t understand the rattling that I hear prior to mine shutting down (shortly after igniting; although the last two times I tested it there was no rattle). I don’t know how to test the thermal regulator/thermostat-looking thing, but I’m going to test the HLS switch as another commenter suggested. Those are the only suggestions in the manual aside from a heat exchanger blockage; might have to KZbin videos for that.

[@pvt-pilot]

Well, I made a video for thermistor. Shows how to test and replace. Check my channel.

[@justindees29]

To test the Thermal Regulator just unscrew the black plastic plug on the manifold and remove the spring which as the regulator on the end. Works just like a thermostat in a car. Boil some water and then put it in the hot water. If it opens all the way up it's good. If it doesn't move and stays shut it's bad.

[@peterphelps7969]

Good job on the diagnosis of the pressure bypass valve, can't believe you found that piston in the t above the check valve.

[@arechj]

I could not find those light codes for the life of me! Thanks!

[@TheFamilyCarr]

nice! I already replaced the thermistor and high limit switch but no deal. I found my stem thing broke off while O was checking the thermal regulator so I’m going to order and replace that, I’m pretty sure that’ll do it. thanks for posting!

[@CrooksTexas]

Thank you. Your videos are very informative and easy to follow. The repair of the manifold part was great!

[@user-rl9mn6cy9s]

Great, great, great!! Doing mine this afternoon. You blazed the trail for me. Thank you.

[@user-uo2pz4xy1o]

Thank you for this! Great video!

[@douglasensley8249]

Great video...you just saved me a lot of money! Thanks! This same thing happened to my heater!

[@bakenasty22]

The tricky part with working on pool heaters is exactly what you see here. You can get an error code and fix that and then the heater will make it past that repaired issue and you run into a new error code. It can be frustrating at times but it’s only going to show you one code at a time and his real problem was the bypass manifold and there is no error code directly for it.

[@mehmetcevikce5193]

Great video. Saved me from buying a new heater.

[@mwoodard50]

Excellent information, and video and sound quality.

[@kernalrom]

Same happened to me. thanks for the video

[@bennetttim72]

Great job, this was very helpful. Thank you.

[@pvt-pilot]

You're welcome! I am glad you found it helpful. It makes it worth it to me (that I bothered making this video) to know that at least someone got something good out of it.

[@emilrasem3321]

Wow this great video saved my heater, thanks

[@fernandoagostinelli]

Good video, very helpful.

[@kevinsmith-pk6xf]

thank you for posting this!

[@evomatic]

Loved this video. I had replaced the HLS switch and the thermo regulator only to in hindsight realize I had heard some clanking and should have known the bypass valve had given out. Question. what kind of wrench do you use to loosen the pipes from the manifold?

[@pvt-pilot]

13mm rachet or ratcheting wrench

[@2Real4U2]

Think he means the couplings on the PVC pipes to manifold? Large Channel locks or you can use a dull chisel or large flathead screwdriver and set in just before the little fins and tap with a rubber mallet till they break loose. Should be hand tightened though so you don't crush the o-rings.

[@ericcarlquist2652]

Great video!!!

[@CharlesCLee]

It is a great video, thanks for sharing

[@arechj]

Excellent video! Also a pilot! :)

[@rosiechapa6058]

Great video I just wish someone would post one with the ALS light coming on. I could not flip my top over like you did in video so I think those are the letters my error is showing

[@pvt-pilot]

I don't know about an ALS light, but I just made a comprehensive video on my AFS light coming on. (Air Flow Switch). You can find it at kzbin.info/www/bejne/noarq5p-p8hsfZI

[@19boggsy]

I was getting an E05 error, so i replaced the Stack Flue sensor. I still got the error after the replacement so i started cleaning out the heater with shop vac. Now when i turn on the heater, the heating light on the panel doesn't come on, but i do see the HLS indicator light up on the system board. the fan goes on for the heater, but the heater never ignites. I don't know if i'm having trouble with the igniter or the HLS switch, manifold, etc. I hate to replace everything if i can't narrow it down.

[@jtm84259]

Awesome video Pilot. Wish you were my neighbor. I have the Mt400 and I’m dripping from one of those 10 bolts securing the manifold to the exchanger. The bottom bolt on the valve switch sensor. Would you think I require a new gasket? Or probably need to disassemble to trouble shoot properly? Thanks a million.

[@pvt-pilot]

Yes sir, take it apart. See if you have any copper tubing left for your O-rings to seal against. Might be time for new coils.

[@jtm84259]

I took off the bolt which I thought was the leak. No water came out. But there is a hole in the actual manifold itself, in the plastic where it indents or crevices to form the bolt housing. Strangest thing. I’m going to kill the water, dry it well, and try and “plug” it with a dab of resin, see if it holds.

[@jimfeilbach3234]

Thanks!

[@christ6370]

Awesome Video! Thanks! Could you help me out since you know so much? Or anybody really. I'm helping out a single lady family friend and her Pentair 250 wasn't working so after a lot of research I changed the Thermistor which got it to fire but then the HLS led lit up and shut it down so I replaced it with no luck. I then found both the Thermo regulator and bypass valve to be broken luckily got them both out. So I left them out and now the heater works perfectly if kept above 3200rpm which seems fine for jets and the 700 gallon spa heats from 75 to 100 in about 45 minutes but if below 3200rpm the HLS led will trigger off and on. I've been racking my brain deciding if those 2 parts are "detrimentally" needed for any reason other than the obvious bypass and heat regulation since it seems to work fine without them. Any thoughts? I'm scared to remove my manifold incase it won't seal back up again because of corroded exchanger tubes. She has had a pool service for years but unfortunately I think he just threw chemicals at it and never really balanced everything else. Now we do our own testing at Leslie's to be sure the equipment isn't being damaged. Anybodys help would be greatly appreciated. Thanks!

[@pvt-pilot]

Without removing the manifold, you will have to live with the symptoms that you have. If you don't replace the manifold bypass valve, by design much of the water will bypass the heat coils and head straight to the hot tub unheated. The water that does manage to wiggle its way through the heat coils will do so at a slower pace than normal since the wide open bypass valve is a pressure reducer in front of the heat coil input. This slower pace will result in more cook time for the water in the journey through the coils which will result in a higher temperature by the time it leaves the coils. If that higher temperature exceeds 120 degrees, the HLS should open electrically causing the control panel to shut down the heater. Then, when the water running across the HLS cools down below 120 degrees, it should close electrically and then the control board will allow the heater to restart again. This abnormal cycle of safe vs unsafe conditions might work enough to limp you along heating a small hot tub, but I recommend replacing your broken parts over relying on your heater's safety checking capabilities.

[@mykoolh9441]

hello and thanks for the video... I replaced my thermal regulator thinking that was the problem but I also have the weird noise that sounds like loud cracking sounds.. does that mean that it's probably not the thermal regulator and the same problem as you with the broken valve? thanks

[@pvt-pilot]

Highly likely. There is not much else in there that will break off and make cracking sounds like that. These thin plastic parts will not tolerate the pool chemicals forever. The spring tension is significant on that MANIFOLD BYPASS VALVE, so when the plastic gets weak over the years, the valve will break and then the water pressure will blow it to the output (toward your pool) eventually if not immediately. Don't run the pool pump at all until you take the manifold apart and see what is broken and making that noise. If you catch it while the broken part is still bouncing around in the manifold, you are doing well in that you will not have to worry about chasing it down through the pipes heading to the pool. That could be a lot of extra labor and pipes to buy. So, shut it off and act now.

[@mykoolh9441]

PVT-PILOT thank you very much.. already ordered the part.. luckily the output goes straight out and then the salt cell is there. I looked at that one pipe and I didn't see anything because the salt cell would have caught it since it can't go through. it must be in the manifold still. thanks again.. you video was very informative and well put together.

[@loreall.2461]

I’m here trying to figure out why my neighbor’s Pentair pool heater is giving off over 2000 ppms of CO2. The exhaust coming out of the stack flu was smelling really bad so I contacted the local gas company. There are no gas leaks in the plumbing but they did detect the CO2 and red tagged it. Any ideas what needs to be fixed to resolve the CO2 and flame out? It’s a MasterTemp as well. Many thanks.

[@pvt-pilot]

Out of my area of experience, but I would think there may be an adjustment on the gas valve assembly in the heater. It sounds like it is flowing more gas than it can burn. If you don't like the idea of messing with internal parts related to the gas output, you might want to just partially close off the gas ball valve in the feeder line on the side of the heater. I can see this being an issue if the gas regulator at the gas meter is not working correctly or if it was increased to a 2lb regulator when the heater was installed. 2lb regulators are frequently recommended but really are overkill.

[@psantini5963]

Those are simple switches , use a multimeter on ohms to check them . Save you a lot of time , aggravation ,and money wasted on changing perfectly good parts

[@pdqcarrera]

Great video. Much appreciated. While I'm ordering parts I'd like to get a spare check valve/cover like you noted at 14:44. Would you please advise the part # you bought?

[@pvt-pilot]

Jandy 7056 replacement. rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F254197594459

[@scalper68]

Thx for this. I'm currently doing the bypass valve repair. As expected the valve was broken (luckily no broken pieces traveled out of the casing). The problem I'm having is getting the casing back together. I can't get it to sit flush. Any recommendations? FYI I'm not close to your level.

[@pvt-pilot]

If you have the bypass valve replaced and seated all the way down, the big plate should push all the way in beyond the thermistor nipple. The only thing fighting you that pushes the big plate back out is the spring that holds the thermal regulator in place. If you are having problems with seating that plate, I recommend removing the thermal regulator and spring by unscrewing the cap of the thermal regulator and pulling the spring and thermal regulator out (see my thermal regulator replacement video). Then, put the big plate back in the manifold without that resistance, and then put the manifold back on the heater, and then screw the thermal regulator back in. You should probably test the thermal regulator while you have it apart. (See thermal regulator replacement video for that too) Cheers mate.

[@pvt-pilot]

kzbin.info/www/bejne/aXa1nnh-nZ19Z9U

[@scalper68]

@@pvt-pilot thx!! Appreciate your rapid response. I already had thermal regulator removed. I was thinking when I bolt it back on won't it compress the plate to be plush? On side note, before I did a bunch of research and found you, the pool repair guy has me test the regulator with kitchen sink hot water which i learned later wasn't hot enough. Long story short I now have two properly functioning thermal regulator lol.

[@pvt-pilot]

@@scalper68 Interesting. I have always used my sink because my water heater output is much hotter than 120 degrees. As for the misalignment, I have not experienced a problem putting it back on so long as you align the manifold squared up flush to the copper pipes. This may be slightly misaligned/misangled from being flush to the tub temporarily if your heating coil assembly separated from the inside of the tub when you took the manifold off. Please note, your tub is NOT what your manifold bolts are screwing into. They are actually screwing directly into the metal face plate of the heating coils that is sitting inside the tub. The bolt holes in the tub that you see externally must line up with the threaded bolt holes of heating coils face plate, so when getting the manifold all squared up, square it up to the heating coils plate even if that plate sags back into the tub a little bit. Replace the O-rings around each copper tube protruding out of the heating coils face plate if you have them handy.

[@scalper68]

@@pvt-pilot all good. Everything working perfectly!! Thx again for your brilliant video!!

[@SONSOFB1TCHES]

I'm going to remake this valve out of brass on a lathe SCREW PENTAIR made to break and require service flat out RACKETEERING!

[@bsatchel705]

Hello. I have an HLS light. The spa heats to approx 91, then shuts off for 2 minutes and comes back on for 90 seconds then repeats itself. The heater runs fine when I am in pool mode. I've replaced my thermistor, HLS and thermal regulator, and I still have the HLS light and all the same symptoms. No rattling or odd noises. It's a 3 year-old heater. Any ideas? Thanks

[@pvt-pilot]

Is your manifold bypass valve broken? If so, this will yield a path for water to bypass the heat exchanger, which results in the water that does make it to the heat exchanger to be overcooked beyond 120 degrees. This will trigger the HLS to open and shut down the heating until the water that is touching the HLS cools down back below 120, which closes the HLS. This cycle will continue.

[@bsatchel705]

@PVT-PILOT thanks for your quick response. I don't know if it is broken or not. I was thinking that the next step is to take the manifold apart and check, but it looks kinda involved. If that's the next most reasonable step, I'll do it, but I was hoping for an easier fix. Thanks again.

[@pvt-pilot]

@bsatchel705 It is the next likely box to check. Grab a 13mm socket and remove those manifold bolts, remove all of the sensor wires and loosen the 2 unions (inlet and outlet). The whole thing comes off as one unit very easily. Pull out the plastic wall inside the manifold, and your Manifold Bypass Valve should be right there sitting sideways in the grooves. Hopefully yours didn't break and take a ride in the pipes like mine did.

[@kandl1484]

My heater fires and heats my spa to 100 degrees but no longer gets to 103, like it used to. My service heater light comes on briefly when I turn on heater, then goes out. I flipped cover and see that I have the AFS light on. Any suggestions?

[@pvt-pilot]

I made a video on my AFS issue. I think your combustion chamber is getting water in it due to a leak in your heating coils. That would explain both symptoms perfectly. You can't reach past 100 degrees anymore because your coils are sitting in relatively cold water in the tub. Also, if you have water in your combustion chamber tub, if will restrict air flow and cause your AFS (AIR FLOW SWITCH) to remain open which immediately triggers the AFS diagnostic LED on your control board. I hope this is not your case, but I think it is...and here is my video that will lay out everything for you: kzbin.info/www/bejne/noarq5p-p8hsfZI

[@philiptaub7733]

Hi, I have a Pentair 250 on NG. Burner fires and starts heating but shuts down in 5-10 seconds. No codes on the ICM. I replaced the flame sensor but no help. Any ideas as to what I should do next? Thanks, Phil in FL

[@pvt-pilot]

You get more diagnostic information from the LEDs on the control board than you can from the ICM (Ignition Control Module). Are there any LEDs illuminated on the control board mounted on the back side of the display/keypad? I am thinking defective thermal regulator if no LEDs are illuminated. Watch all of my videos to get a good idea of the way this heater works. It is a fairly simple unit but understandably has multiple safety stops for various potentially hazardous failures.

[@philiptaub7733]

@@pvt-pilot Thanks very much for your reply and the helpful info. I reassembled the unit and now it works at least in "pool" mode. Don't understand why it doesn't operate in "spa" mode. In fact it threw a "3 blinks" code on the control board when in "spa" mode.

[@hoopkido]

Do you have experience with non firing, and no led lights other than service heater?

[@pvt-pilot]

Not much experience non firing without diagnostic LEDs illuminated, but you might try looking at your ICM (Ignition Contol Module) which is the metal box approx 9x9 that sits on top of the heat exchanger that has all of the wires that connect to your control board. There is a red led in there. Read the label inside the box that says what the led is indicating. If it flashes 3 times repeatedly, that means ignition lockout if I remember correctly. I also had a defective thermal regulator video that caused service heater without diagnostic LEDs, but it would light for 20 seconds before going into service heater status, so that doesn't sound like apples to apples.

[@SONSOFB1TCHES]

MADE TO BREAK!! I have had this problem to many times to count. this pentair POS valve should obviously be made of brass.. The best way to keep it from happening is when you backwash pull the valve slowly because the sudden flow of the backwash can break this tiny plastic POS. If you want something that LASTS make it your self oh wait you cant because it would have to be "energy rated" and osha approved. This should be outlawed, pentair should be sued by every single customer in a massive class action.

[@sammysaenz6340]

Error code E05 had SFS light up, changed SFS sensor, master temp 400 stayed the same would turn off after 20 sec. with E05 code. Took off manifold found filter rib debris holding the bypass valve open, cleared it, flushed the coils, nothing, same E05 code. So frustrating, can anyone help before I call a tech and waste an arm and a leg.

[@pvt-pilot]

E05 is still stack flue sensor "open". I bought non-OEM stack flue sensors 3 times before getting a correctly calibrated one. If your still getting E05, don't stray from the indicative problem...the stack flue sensor. Take WD-40 and scratch clean the spade connectors of the stack flue sensor on both ends. When your heater starts up and you are heating in spa mode, hold down the SPA button on the membrane keypad on the top of the heater for 5 seconds and it should display the temperature that the stack flue sensor is reporting. If it doesn't, well there's more confirmation that you're dealing with a faulty SFS and/or wiring to the SFS. Watch my video about thermal regulator replacement, and near the end of that video at 6 min 30 sec, I demonstrate how to check the SFS temperature. Here is that video: kzbin.info/www/bejne/aXa1nnh-nZ19Z9U

[@hperez6266]

How much for the repair?

[@pvt-pilot]

Go to eBay and search "Mastertemp Manifold Bypass Valve" and you will find the kit around $33-$41 that includes the spring and slip in wall piece too. I got mine for around $14 but the kit number I bought in this video only had the broken valve (no spring, wall or circlular top piece)

[@AquaTech225]

Internal bypass causes all that clunking ect. You also valve corrosive water. Your chemistry has been out of whack a number of times

[@pvt-pilot]

You are correct about the corrosive chemistry. I used to just throw chlorine, acid and shock at it when algae came. I didn't learn until about a year ago how to test and balance the chemistry. Corrosion damage over the years to my equipment has been rather extensive.

[@yorgelisgomez3871]

Hola

[@yorgelisgomez3871]

En español

[@bills1995vette]

Pentair sucks.

[@bills1995vette]

Company should be sued.