1.5yr old Weil-McLain EG steam boiler with loud buzz at the vent damper

azzzz · August 4

I have Weil-McLain EG steam boiler, installed 1.5 years ago. We've already had electrical problems and a shorted transformer and had to have wiring replaced.

At end of winter it started buzzing loudly (see video below). We had a plumber come who said its the vent damper based on the video and would be $575 to replace. Because of the electrical problems, I had an electrician take a look but but when we ran the boiler for 15 minutes it was silent.

The electrician says don't replace the damper until we know whether something upstream is killing it and to wait until winter, and if it buzzes again he'll test for a short then.

Does this make sense? Does this sound like a broken damper and is this likely an electrical issue or something else?

https://files.catbox.moe/2w74ba.mp4

Thank you!!

STEAM DOCTOR · August 4

There is no good way to know, without testing. Would involve isolating components, testing ... The vent damper might be the problem or might be the symptom.

mattmia2 · August 4

i'm curious to see how this is wired. loose connections or burned contacts can cause things that are powered through them to buzz. the flue damper could do it on its own too or could even be telegraphing normal vibration.

if it burned out the fuse in a transformer and you are having other problems now there is likely either sloppy wiring in the new install or it was connected to old t-stat wiring that was sloppy or deteriorated.

azzzz · August 4

https://forum.heatinghelp.com/discussion/comment/1901394#Comment_1901394

Thank you! Would a regular electrician be the one to look at that? Is there a way for me to tell "how this is wired" by looking at it or uploading a picture of something?

mattmia2 · August 4

pictures would help to tell if they knew what they were doing at least. a heating contractor should know enough about electrical to do a neat and correct job of connecting it to an existing circuit. the problem could be in the circuit before the boiler too. a problem with the circuit it is connected to is unlikely to burn out a transformer but it could have been a misdiagnosis.

EBEBRATT-Ed · August 4

@azzzz

Where is the original installer? Long gone? Probably not a job for a plumber if he is just a plumber. You need someone who know electrical and controls.

I have a suspicion that since you have already burned out a transformer and replaced wire that the original electrical portion of the job may not be up to snuff.

can you post a few pictures?

Steamhead · August 4

If that is a Field or Effikal damper (same basic unit) you don 't need to replace the whole thing. The motor drive can be replaced- takes about an hour. For some reason I can't get the link to work, you'll have to copy and paste:

https://www.supplyhouse.com/Field-Controls-70009800-GVD-Vent-Damper-Motor-Assembly-Metal-Base?utm_source=google_ad&utm_medium=Shopping_HVAC&utm_campaign=Shopping_X_HVAC_X_SSC_New&utm_campaignid=22357738074&utm_adgroupid=176777929837&utm_targetid=pla-2435666339679&utm_product_id=70009800&utm_matchtype=&utm_keyword=&utm_adtype=pla&utm_category=HVAC&gad_source=1&gad_campaignid=22357738074&gclid=Cj0KCQjwm8bTBhDWARIsAC9Hi8lTto0FO8xbH67wk8pykZGzQzFNqqIYfia6xVdKYIohX-Cm8GyLF4waAi53EALw_wcB

azzzz · August 5

Thank you all! Here are photos of the boiler, near-boiler piping, and all the wiring I could see. Unfortunately the original installer is effectively long gone. Happy to take more of anything specific.

mattmia2 · August 5

Why are there 2 transformers? If one is running the zone valves and the other the boiler then they need to be isolated, the only thing connected to the boiler from the zone valves should be the end switches on the zone valves and the zone valve transformer should not be connected to the end switches of the zone valves.

one of the end switches in the zone valves could be not making well and causing the noise too.

why did the boiler get replaced?

edit:

er it is more complicated, there is a 3rd transformer i think for the zone panel on the side of the boiler.

you need a good heating contractor to trace it all out. it isn't super complicated but it is a little complicated with the hot water zones.

STEAM DOCTOR · August 5

That transformer in the ceiling is suspicious. Only two transformers that should be in play, sre the one inside the boiler cabinet and the one that's part of the relay for the hot water zone.

STEAM DOCTOR · August 5

Is the green switching relay, on the left hand side of the boiler, a zone valve switching relay?

STEAM DOCTOR · August 5

You said that wires were replaced. Which ones? You mentioned a shorted transformer. I am assuming that you mean a dead transformer. Was there any indication that there was a short within the transformer itself?

STEAM DOCTOR · August 5

When did these problem starts? Immediately upon installation of the new boiler or at some point afterwards?

STEAM DOCTOR · August 5

Sorry for repeating some of the things that @mattmia2 said. Missed that post

azzzz · August 5

Thanks all, this is enormously helpful. Answering what I can

The boiler was a replacement of an old oil heating system. The initial plumbing contractor converted our system to gas and this new gas boiler.

The boiler worked for the first winter but wouldn’t turn on the next winter. We were told the transformer was broken so we replaced it but it only worked for a bit before breaking again. We then had an electrician replace the wiring from the thermostat to the boiler— he said that it was shorting out the transformer. Not sure exactly what was tested at that time. After that, the boiler was working well before it started making that noise.

Photos below of the green relay. I am not sure about the ceiling transformer (what that is or when it was installed). Photos below, including where the wires run.

I have steam radiators for one zone / plus hot water baseboards for 2 zones. Hot water comes from a separate water heater.

EBEBRATT-Ed · August 5

I don't see any condensate returns. Guessing its counterflow.

I don't care for the Romex on the circs & Sw relay.

kind of messy wiring needs to be cleaned up.

STEAM DOCTOR · August 5

In all likelihood, the issue is in the boiler wiring and/or controls. Thermostat wiring was replaced. Most electricians struggle with boiler wiring. In my experience. Many boiler techs, struggle with wiring issues as well.

STEAM DOCTOR · August 5

Did the boiler ever run, without noise, after the second transformer replacement/ thermostat wiring replacement?

mattmia2 · August 5

my bet is that when some combination of things are calling for heat that the transformers get connected in a problematic way, either they get in series and produce 48vac or they get connected in parallel out of phase.

a 2 zone zone control to control the circulator and call the boiler on the aquastat would have made things simpler

what you should have with what you have now:

you should have the zone valves and their thermostats wired individually on their own transformer
with their end switches paralleled
calling the single zone controller then
the single zone controller turns on the circulator and calls the boiler through the aquastat so it doesn't reach steaming temps.

109A_5 · August 5

The video seemed quiet. When it is buzzing does the boiler fire ?

109A_5 · August 5

Places I would measure voltage at when it is acting up, (everything connected normally) to determine if the voltages are correct. If the voltages are all correct the Damper may be the issue. Finding the right person to do the troubleshooting may be the hardest part.

EdTheHeaterMan · August 5

There is a lot going on here. The noise in the video sounds more like a "hummm" and less like a "buzz". And most of the regulars here know what I recommend for HVAC equipment that "hummmms". Humming usually happens when you forget the words. If you can find the sheet music with lyrics and place it within view of the boiler, the humming will stop 90% of the time.

Now if your boiler is part of the 10% where that does not work we can look further

A LOT GOING ON:

You have three thermostats that operate that boiler.

One thermostat operates the boiler to make steam for the majority of the home. That is the normal way that most people use this boiler… and @109A_5 has covered that. When there is a call for heat from the thermostat the boiler makes steam and the radiators get hot.

The other two thermostats are a little more complicated. They operate zone valves this the how I would connect your zone valves to those thermostats and the transformer.

This diagram is modified from the instruction manual provided by Honeywell/Resideo for wiring a zone valve. you can see that the extra transformer that is attached to the wall is illustrated on the upper left of the drawing and provides 24 volts to power the zone valve motor on a call for heat via the yellow leads.

Once a zone valve opens you need to operate a circulator pump to move the heated water thru the baseboard zones. This will be accomplished by way of the Red leads auxiliary switch commonly referred to as the end switch.

That end switch operates the Taco SR501 relay that can operate the circulator pump. The SR501 can also operate the burner in the boiler in order to get the water in the boiler to get hot. but we dont want the boiler water to get too hot so it makes steam so we need to add an operating limit control close to the tankless coil that is the source of the heated water for the baseboard loops. This control is already on the boiler wiring diagram as an optional OPERATING CONTROL (with note 9). I have illustrated that control in green below:

Under normal conditions this would be used if that tankless coil was used for domestic hot water (DHW) but in your case that coil is the heat source for the hot water baseboard zones. Now the way that control is connected here would make the boiler maintain temperature all year long. Since the boiler only needs heat when there is a zone that is caloing for heat U would modify the diagram so the burner only operates when one of the thermostats is calling for heat. That Zone with the steam radiators is already covered in my earlier statement (just after the sheet music option). The other two thermostats operate the zone valves and those valves have End Switches that we connect to the SR501 to operate the circulator pump. Now all we need to do is to add the SR501second relay contacts to the operating control circuit and the burner will only operate when there is a call for heat from a thermostat.

The following is a complete system wiring diagram as I might assemble the system:

If you have any Questions. feel free to post a question or send me a PM.

EdTheHeaterMan · August 6

O yea… @azzzz… I forgot to say that the sound may not be from the vent damper. That may be a zone valve motor that has failed and keeps spinning endlessly. OR… from the circulator pump if there is air in the hot water loop.

It might also be from the damper motor but that would be from wires being connected incorrectly and that would explain the transformer failure. Many electricians are not well versed in low voltage control wiring. That said, your electrician may have made some incorrect assumptions about how the thermostats get connected. If somehow the transformers are not on isolated circuits and somehow get cross xonnected, that will cause transformer failure for sure. I suggest showing the electrician or HVAC / Plumber technician the diagram in my last post where ALL the components are illustrated as one complete diagram and not separate diagrams from each part of the system.

109A_5 · August 6

The reason I focused on the boiler wiring is the transformer inside the boiler appears to be the power source for the Damper. Regardless where the call for heat originated the Damper has to work correctly for proper boiler operation.

Does the boiler fire every time when expected and remains active until the call is satisfied ? Does the shaft on the Damper (between the motor assembly and the vent pipe) turn continuously ?

EdTheHeaterMan · August 6

https://forum.heatinghelp.com/discussion/comment/1901470#Comment_1901470

Agree with you, @109A_5, but the noise in the video does not sound like the vent damper is turning because there is no noise that is associated with the flexible edges of the damper blade scratching the inner surface to the damper. that could mean that the damper blade is not properly connected to the damper motor or it could mean the damper motor is not the source of the noise.

Another clue is the fact that a transformer needed to be replaced and wiring needed to be replaced. That tells me that there may be a low voltage wiring problem. if the three transformers (zone valve transformer, SR501 transformer and the Weil McLain boiler transformer) are not isolated as I have shown in the diagram above then you will keep using up the factory installed smoke inside the transformers until that incorrect wiring is corrected.

Until then perhaps they can install my world famous "Smoke Keeper" so the current transformers don't loose their factory installed smoke.

You don't need to purchase this from me. Just pick up the necessary parts at the auto store.

109A_5 · August 6

"loud buzz at the vent damper"

I did not hear a loud buzz in the video, in fact I had to turn the computer's volume all the way up to hear anything in that video. So I am confused at what the video is representative of.

The other thing I am skeptical of is;

"We then had an electrician replace the wiring from the thermostat to the
boiler— he said that it was shorting out the transformer. Not sure
exactly what was tested at that time. After that, the boiler was working
well before it started making that noise."

There does not appear to be 3 wires to a thermostat. So I am skeptical that 'shorted' thermostat wires would damage the transformer. Maybe just keep the boiler running when it is not needed. Maybe there was a short to a conduit or an equipment ground, since it looks like the low side of the boiler's transformer is grounded.

azzzz · August 6

I truly appreciate everyone's help with this. I will definitely discuss this all when I have this looked at again. Thank you!!!

1.5yr old Weil-McLain EG steam boiler with loud buzz at the vent damper

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