Boiler Down

Jeff_133

For some reason, my steam boiler (Dunkirk 225K btu) is down, and I can't find an explanation.

- Pilot is working (thermocouple was just replaced yesterday)
- Water level is sufficient
- Thermostat is operating properly (I swapped out to make certain)
- I should note it is a leaky boiler, but this has been an issue for some time, and it hasn't gotten any worse.

All was fine earlier today. Starting its nighttime thermostat cycle at 5:00PM the boiler was fired up, but now it's just sitting there idle, even though the thermostat is far from satisfied. I stepped out for a couple hours, so I don't know when it went down.

The only thing odd I noticed earlier was as it was beginning the night program, the boiler was short cycling a bit, coming on for about 90 seconds, then shutting off. Then it stayed on, so I didn't think much of it.

If anyone has any suggestions on how I can diagnose this issue, please advise!

Thanks very much.

Timco

do you have a probe type low water cut off? if so, it may need to be cleaned. Waterline is good? pressuretrol is the next thing after LWCO...

Tim

Jeff_133

yes, i have a

probe type LWCO. It has an indicator light on the top when it is tripped. But that is not on right now. Could this still be it? If so, can it easily be removed for cleaning?

If not LWCO, how would I diagnose pressuretrol?

I'm attaching a pic for you.

Jamie Hall

I don't suppose

that there is a second low water cut off somewhere? Many larger boilers have such a critter, and it is usually a manual reset...

Timco

If it was the probe, the light would be on. try flicking the switch on the vent damper to 'open' or 'manual'. It may be stuck or bad. Pressuretrol diagnosis takes a electric meter to see if voltage is getting across.

Tim

Timco

Also need to check transformer voltage. They die too...but the vent damper or a reset somewhere is pretty common...

Tim

Jeff_133

2nd LWCO

I don't think I have one of those, but I could check the stat sheet...

carter_3

if it ran for a short period and stopped and the power light is on at the low water cut off sounds like the blocked vent (spill switch )is tripped

Jeff_133

vent damper is

working A-OK. This is how I know the thermostat was working too. I checked the voltage at the thermostat, and at the boiler to make sure i had continuity. i get 24V, so I figure the transformer must be OK as well. when I trip on the system, the vent damper opens, and when I shut off, it closes. I have a volt meter, so where should I check the pressuretrol, and what am I measuring?

Jeff_133

clarification

i assume the LWCO is getting power, since everything else is, but the indicator light at the top that goes red when water is low is NOT on.

Timco

continuity when calling for heat, open when satisfied. 24v through it. You can try jumpering the presstrol as well. 24V at gas valve when calling? If so, maybe a gas valve, and leave that to a pro...

Tim

Jeff_133

ok

will check the pressuretrol and will also check the gas valve. understood gas valve is off limits in spite of how cold it is in here but i may come back to ask how to jump pressuretrol... back in 5...

Jeff_133

i checked...

across the gas valve leads. see attached pic. no 24V to be found. i also checked pressuretrol: i placed voltmeter probes across screws that secure the wires (one from t-stat, other into the LWCO/Feeder/damper/valve spaghetti). no 24V there either. am i checking the right spots?

Timco

Follow the voltage from the transformer to the gas valve through the t-stat, LWCO, pressuretrol, and spill switches / damper assy. It must stop somewhere.

Tim

Randy_30

This probably is a stupid question but is this steam or water? I ask because no one has mention a flow control. It could have failed or more likely since he mentioned it short cycled that it could be a pump problem.

Jeff_133

following 24 V

i checked the circuit at the LWCO - the outputs that go to the gas valve have 24V across them with the thermostat on and unsatisfied. I lowered the temp setting so the t-stat was satisfied, and this output read 0V. 1) It is correct to state that this confirms the LWCO probe is working? 2) one of the leads from the LWCO goes to the gas valve, the other goes to a little doo-dad (sorry, i don't know what it is) that sits inside the boiler cowling. See attached pic. Perhaps this a problem since it has become corroded due to the leaks. What is it? and can I safely by-pass this sucker until I find a replacement?
PS - I still can't explain why I don't have 24V at pressuretrol...

Jeff_133

it's a steamer

sorry, i should have mentioned that!

Timco

Looks like a roll-out switch of some sort. Take the wires off it, and check it for continuity. If none, there is your problem. Jump it out for tonight and replace it tomorrow...

Tim

Jeff_133

OK!

I will give it a try! THANK YOU. I will post when done.

Jeff_133

WHOO HOOO!

That was it!!! Back on! Man, what a beautiful sight! Tim, THANK YOU!! Where should I look for the replacement part??

Timco

Look up your boiler's mfg on line and find your local rep, then the local retailer to get that safety switch...you MUST replace it...promise you will...

Tim

Jeff_133

i promise

to replace it ASAP. i don't mess around. i'm hoping i can find it locally tomorrow. as i write this, my radiator vents are wide open and making room for steam! THANK YOU!!

John T_3

Not a good idea, leaking boiler, open roll-out switch, no suggestion to check the combustion side of the boiler. Jump out the safety? Boiler could be sooted and rolling out. Hope there's someone still alive to change that roll-out switch tomorrow.

Jeff_133

ok, i am here

all is working, but help me understand your concern. what do you mean by "rolling out" i am trying to track down the part right now.

Unknown

If the flue passages in the boiler are restricted, or the flue pipe is blocked, the gas flame will "back out" of the burner area to the outside where that switch is located. When the switch is heated it opens the circuit to the gas valve as a safety measure. It is not resettable so it must be replaced and the boiler checked for possible malfunction. With that much visible rust, it is possble that the boiler fireside passages are blocked, causing a flame rollout condition. Better get it checked ASAP!

Jeff_133

got it

once i found the wiring diagram ;ast night, i understood the use/need of the switch. i don't think i have a flue restriction, but nevertheless, the system is off now, and i am searching for the part. thanks for the info!!

Jeff_133

Boiler Up

Thanks to the help I received here, my boiler is up and operational again - for now

Here a pic of the new flame out switch installed. Thanks to Tim for all his help last night.

Cheers,

Jeff