Boiler Wiring for Beginners: Basics on how residential hydronic (water) boilers work

I rip out 100% of residential boiler wiring systems fully intact to show beginners how many boilers are wired. In this video I will cover the components of an older Crown boiler with a L8148E Honeywell aquastat and Honeywell 4 wire zone valves.
00:00 Introduction
00:40 120 Volt Power @ Aquastat
01:36 T, TV, Z and W Terminals
02:25 Zone Valves & Thermostats Overview
03:06 T & T Circuit Concept / Wiring
04:27 Zone Valve Motor Circuit Off Z To TV
06:27 Zone Valve End Switch Circuit Off Z to T
07:06 Aquastat Internal Relays / Controls
08:30 Burner Circuit: Spill Switch, Roll Out, Gas Valve
10:09 Powered Demonstration / Sequence of Operation
HVAC / HVAC Training

[@Travac89]

Yo your about to quit your job and make millions! This channel has it! Keep doing what your doing. This is way more informative than other channels and t helps me with wiring a lot. I get stuck and your videos are helping me out.

[@JerseyMikeHVAC]

Awesome. Glad it's helping you out! I can use a few million!

[@danielbromley1410]

I’m

[@PJam2019]

These videos are SO invaluable to an apprentice it is unbelievable. You're one of the best channels to share with techs both new and experienced to brush up their knowledge of this stuff. Thank you for this.

[@JerseyMikeHVAC]

Appreciate it, Thank you.

[@XavierTheNerd]

Thanks for building this demo, this is a whole apprenticeship in one video!

[@haroldlm64]

Great demonstration.

[@kevindick7485]

I had no idea the components but you bare bones visual creates a better presentation . The dry run of time and as the actual devices coordinate great example .

[@EdmarcioGuedes86]

Thank you so much for this video. I'm a plumber apprentice and that's one of the things I have to deal with sometimes a week. I wish I had seen this video a year earlier 😅

[@Jnash2030]

this is by far the best wing breakdown Ive found. Much appreciated!

[@JerseyMikeHVAC]

You're very welcome

[@pipers255]

I'm learning the electrical late in life, i would say, I'm 55 and the company I worked for closed and we would do all the plumbing on boilers but not electrical, now I'm in a new company that also does electrical and your videos are real clear and helpful i really really appreciate you thank you

[@JerseyMikeHVAC]

Thanks. You're welcome.

[@boobachelli]

You have a gift for explaining things. Learning more about 24 volt especially, through you rather than class!!!! Please keep the videos coming!!! Some of the bigger channels are good but yours is something easier for the beginner to understand. Subbed and upvotes across the board

[@JerseyMikeHVAC]

Really appreciate that. Thanks!

[@ClaytonBoyle]

This video most closely describes my setup, which is a 70 year old Capitol Boiler. I have no damper or zone valve, but do have two separate 24v transformers in addition to the internal transformer in the Honeywell switching relay. This thing is ancient yet makes me feel quite dumb sometimes. Thanks for the great content.

[@JerseyMikeHVAC]

Yeah I've had a few that made me feel dumb too. Ha.

[@nonoyrafael9505]

Awesome! Remarkable demonstration! Big thank you Mike!

[@JerseyMikeHVAC]

Very welcome!

[@amaurycruz5512]

Finally the video that was looking for long time,thank you Jersey Mike

[@JerseyMikeHVAC]

Youre welcome

[@shawnpatriciashalabieh5063]

This was a very useful video Good job . Very nice explanation. I was waiting for this video .

[@NROhvac]

Your the man mike! Thank you!

[@JerseyMikeHVAC]

No problem

[@escobklyn2696]

Awesome man thanks!!

[@davepham6904]

Thanks for the information bro. It is useful ❤

[@tenzinlhawang9792]

Very useful 🙏🏻

[@rickytillery2676]

That was good Great teaching

[@JerseyMikeHVAC]

Thank you!

[@tomhughes4980]

Great video, now add a power venter on oil burner

[@cpaul57]

Better then my instructor at Raritan valley community College. School is a complete joke

[@JerseyMikeHVAC]

Thank you. You're not the first I've heard say that about schools, unfortunately.

[@crespino1492]

Thank you thank you

[@JerseyMikeHVAC]

You are very welcome

[@eli2fly103]

Very helpful. Can you do videos on steam boilers as well?

[@JerseyMikeHVAC]

Yes, I've had a few request and I'm going to try to work that in within the next few weeks or so.

[@paulettesingh6055]

Any video on pse 802 mcdonnell low water cut off wiring

[@paramountx]

I basically have a system like this. How do i make a c wire? Connection?

[@leftherisioannou6583]

I have a building in Bayonne can you check my boiler I have a problem with water level in a 1 pipe steam system Ted

[@shawnpatriciashalabieh5063]

I have to thank you again. And what about ignition control module. Spark . Is video coming about it.

[@JerseyMikeHVAC]

No problem, Shawn. The next time I tear out a boiler with a control module in it I'll put it aside and make a video at some point. I plan on making a few boiler wiring videos with different arrangements, so I'll be sure to work in the module when I get there.

[@NROhvac]

Thanks for what you do Mike, I really appreciate it and I’m sure others do as well

[@JerseyMikeHVAC]

I'm all about giving people a little help. Thanks Nick!

[@namskramskram6009]

IS that W terminal for low water cut offs? Just guessing based off what you said. I have to repair boilers in my area but we have like 6... and I'm the senior tech after a year and I have noooooo idea what I'm doing lmao. My company teaches you on the job and with as little amount of boilers as we have I need to learn everywhere I can.

[@JerseyMikeHVAC]

That cam be tough! The W terminal on those transformers are not usually wired in on the backside at all. It's actually a dummy terminal that can be powered and used for other accessory items if desired (like if you had a hydronic loop off of the steam boiler and wanted to power a zone valve or something). LWCOs are powered off of the R terminal directly in most cases.

[@mr.handyman6232]

Great videos, Can you make a video showing how to wire up a circular pump on a hot water system boiler

[@JerseyMikeHVAC]

Most of them will have either an aquastat, in which the circ pump connects to C1 and C2 terminals, or there will be a molex plug from the circ that connects inside the boiler. Switching relays can vary but wiring diagrams show you where to make the circulator connections.

[@mr.handyman6232]

@@JerseyMikeHVAC you need to open a course in a school… you’re very talented…

[@JerseyMikeHVAC]

Seriously thinking about that!

[@dsdsdsdsddsdsdddsd]

One question: which one would be used as c terminal if my thermostat requires a C terminal?

[@JerseyMikeHVAC]

Do you have a transformer on the wall? An aquastat? A relay board?

[@BaconJD420]

Thank you, but I don’t think anyone has explain this clearly to me as you have

[@RonJLow]

Some digital thermostats are looking for a blue C wire (common). Where is that in this system?

[@JerseyMikeHVAC]

It always goes back to a transformer common terminal. Sometimes that's I side the aquastat.

[@JerseyMikeHVAC]

Always goes back to common on a transformer somewhere. I have videos on where the common is when hooking up smart stats.

[@TLCTugger]

@@JerseyMikeHVAC Thanks, I removed a cover and found a bar with a bunch of terminals with labels like C, R, and W.

[@missdhara6434]

Can someone please help? I installed a new gas bolier recently. But for some reason the boiler is running without reading the thermostat. Is this a faulty wiring or something to do with the boiler installation? The thermostat is getting power, it reads the time and measures the temperature in the room, but it doesnt regulate the house temperature set on the thermostat with the boiler . Its set at 70 but the house temp is 90! Is this a wire burnt out or is it a faulty installation?

[@tonymanero5544]

The thermostat starts the controller, and continues to send a low voltage to the controller until your set temperature of 70 is reached. The controller is continuously receiving a low voltage from the thermostat to run the circulator and fire the boiler. Turn off the thermostat, and the controller and boiler should stop running.

[@markharris1683]

What's going on Mike I love your videos how about on a steam boiler you don't have a aquastat on a steam boiler is the wiring the same

[@JerseyMikeHVAC]

It's a little different. I have a video on steam boiler wiring. Check it out.

[@MrRadiodio]

what if my aquastat does not have that stepdown transformer in it ?

[@JerseyMikeHVAC]

Usually in that case there is an external transformer mounted somewhere nearby.

[@emmanuel.alcantara]

Can you draw the schematic ?

[@guzman953]

Mike where in Jersey u located

[@JerseyMikeHVAC]

I'm in Bergen County right on the NY line.

[@guzman953]

For service can I get your info

[@JerseyMikeHVAC]

[e-mail]

[@guzman953]

@@JerseyMikeHVAC email sent

[@guzman953]

Mike did u get my email

[@MT09Boi]

After watching the "how to wire a zone valve for beginners" video, I was like "oh, thats easy". Now I watch this and am confused on how the transformers off of the 120V circuit and the end switches going back to T1 and T2 in the previous video aren't even mentioned. Did the other way not have a aquastat?? Because then how does the circulator get kicked on in the other one then. I was found and now am lost again.

[@JerseyMikeHVAC]

Yeah in the zone valve videos there is no aquastat. The circ pump activates from a signal originating from the boiler control board. In this video there is an aquastat, and all of the parts came off of an older boiler with a standing pilot flame and no control board. In this case the aquastat acts like the control board.

[@MT09Boi]

@Jersey Mike HVAC ahhhh, that makes sense. I've been the lead Residential Forced air installer for a while and I'm trying to learn more about boilers/hydronics to further my capabilities since the old-timers don't want to teach and bring me on their jobs so they have job security haha. Thanks for the help!

[@rickychavez1473]

🫡🫡🫡

[@MiceNine9]

Fun Fact: if you lay out all of the wiring from a single boiler unit, end to end, the boiler stops working.

[@JerseyMikeHVAC]

I disagree. This thing will fire up on a picnic table if I just hooked gas up to it. Add a tank and some water piping and I can heat a pool if I wanted to.

[@sergeiperez8349]

@@JerseyMikeHVAC great response to the hater!

[@migueldominguez7962]

You need to slow down a bit!! You go so fast. Are you double parked or something??

[@ramatraghubir1295]

Mike ramat new York some people a borm to b explicitly. U should open a boiler trade shool.electrician

[@JerseyMikeHVAC]

Actually thinking about it.