Steam boilers got me stumped!

mpecor

Recently my steam boiler start acting up. It's a single pipe Weil McLain system. When the thermostat calls for heat it will initiate the pilot which will causes the main burners to light. Burners stays light for approx 60sec and it will shut off this is repeated several times until finally it remains lit and the cycle completes. This is a new problem and I don't know where to start. Any help would be greatly appreciated.

MilanD

Flame sensor needs cleaning or replacing. It's not reading the burners being lit. Or flue blockage spill switch getting hot. Some kind of safety is getting triggered.

What exact model?

mpecor

MilanD, it's a Weil McLain EG-40-PI. Powered by natural gas. ..It is old approx 30+years. If I can get away with replacing a relatively cheap component and buy another year or two I will. On the other hand if the time has come to open the checkbook and replace the unit so be it.

SeanBeans

@mpecor where are you located?

lchmb

Have a good service provider come in and take a look at it. Sounds like a simple repair should get you back in running order.

newagedawn

what cycle? burner or heat

JUGHNE

If you still have the original T-stat from 30 years, it might be the HW round type with the mercury bulb. I have seen the heat anticipator act up to short cycle the burners and then decide to stay on.
If you have a mercury type, you can remove the front cover and watch the bulb with mercury travel back and forth. Turning it to max high temp will usually keep the signal on.
This is the first thing I would look for.

Then burner, pilot, flame sensor clean just for good measure also.
Most would not replace steam boiler this "new" unless it is leaking water. There is not a lot of efficiency to gain for ROI--IMO.

mpecor

@SeanBeans I'm in upstate NY
@JUGHNE I do have a newer digital t-stat.


I did clean the flame sensor this morning and had quite a bit of build up. Enough build up to where I assume it wasn't touched when I had the boiler cleaned and serviced in September. I bumped the t-stat up and it ran fine. I will watch it for a couple days and see if it was a fix that simple. Here's to hoping!
I read that using something to abrasive to clean the sensor could cause grooves which would enable quicker build up. I used a damp rag and let it dry thoroughly before reinstalling. Is there a right and wrong way to clean the sensor?
Lastly I'm grateful for all of your input. As a first time home owner and I first time steam heat guy I am out of my element. Thanks you

JUGHNE

You sound like a handy HO. If you want to learn more about your steam system there are several books here available on the "Store" above. The first book shown by Dan Holohan , The Lost Art of Steam Heating will tune you in to your steam system.

As you may suspect after your Sept. tune up there could be a lot of things overlooked with the quick service call.

Tim McElwain

What are the control numbers on your gas valve and ignition control?

Cleaning the sensor can be done with fine steel wool or a soft clean emory cloth. Do not use any cleaners.

Steamhead

30+ years old, I'd bet it's the White-Rodgers spark-to-pilot system.

@mpecor , does the ignition cable come off of a white plastic box?

mpecor

@Tim McElwain model:36c84
24v. 60hz 0.6amps
Maz. PR. 1/2 P.S.I.

@Steamhead It is indeed a White-Rodgers spark-to-pilotsystem

Tim McElwain

That is a White Rodgers Cycle Pilot System. What are the three numbers after the 36C84- ***. Most of the time cleaning the pilot orifice on a Mercury type pilot will solve the problem. The tip of the sensor has to glow "Cherry Red".

Th other problem with these is the built in pressure switch in the gas valve. If that is the problem then the valve will need replaced. Those valves have become difficult to get in recent years.

Tim McElwain

This might help:

On Amazon

White-Rodgers / Emerson
White-Rodgers / Emerson 36C84426 36C Series Cycle Pilot Gas Valves
5.0 out of 5 stars 1 customer review
Price: $119.95 + $7.90 shipping
Only 1 left in stock.
Get it as soon as April 6 - 10 when you choose Standard at checkout.
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Specifications for this item

Part Number 36C84426
Number of Items 1
Brand Name White-Rodgers / Emerson
Item Weight 2 pounds
UNSPSC Code 40141600

JUGHNE

I had one of these that the tiny cap tube broke off of.
No replacement thru regular channels other than put a standing pilot/T-couple valve on. Did so and had no problems.
(Yea, I know standing pilot......but you have minimum monthly gas bill anyway)

You could not change to standing pilot if you have a motorized flue damper, usually.

Tim McElwain

Weil-McLain does not authorize standing pilot replacement for this system. They provided a kit which was a factory authorized replacement which converted the system to a Hot Surface Ignition system.

JUGHNE I hope you did a pilot safety turndown test after that retrofit to thermocouple.

j a_2

MilanD said:

Flame sensor needs cleaning or replacing. It's not reading the burners being lit. Or flue blockage spill switch getting hot. Some kind of safety is getting triggered.



What exact model?

If it was the spill sw. And it did trip,it would not restart without manually resetting it....but resetting it is not the fix, why it tripped is the issue

MilanD

> @j a said:
> Flame sensor needs cleaning or replacing. It's not reading the burners being lit. Or flue blockage spill switch getting hot. Some kind of safety is getting triggered.
>
>
>
> What exact model?
>
> If it was the spill sw. And it did trip,it would not restart without manually resetting it....but resetting it is not the fix, why it tripped is the issue

Could have been a windy day and getting backdraft.... Or you may have blockage in the chimney. Got to inspect. But, if it did it once and no more, just keep an eye on it..

I had a Smith water boiler trip it on the burner side when I removed the door to light the pilot.. Turned the burners to look at flame, tripped the heat spill sitting above the door. Put the door back on, no problem. So check that all the enclosures around the burners are all in order.

j a_2

My point about the spill sw was the op stated it just cycled on and off..If it were the spill sw it would not cycle on its own. As that is a manual reset safety....

MilanD

> @j a said:
> My point about the spill sw was the op stated it just cycled on and off..If it were the spill sw it would not cycle on its own. As that is a manual reset safety....

Ah, I missed the point.

Tim McElwain

Haven't heard from MPECOR since April 1, I wish people would come back and tell us it got fixed and what they did to fix it.

newagedawn

when was the last time it was flushed or skimmed , after 30 yrs it sounds like its time