I have a Lochnivar hot water boiler. About 3 weeks ago I used my shop vac to clean up the soot that had developed at the base of the unit and at the base of the burner compartment. Nothing crazy, just figured it would be the right thing to do.

Shortly after the light cleaning, I woke up with no heat in the middle of the night. After doing some investigating, I found the roll out switch on the burner tray was tripped. I pushed the reset and the unit started up.

No problems with unit until about 10 days later, same issue, woke up in middle of night and reset the roll out switch. Unit fired up and worked fine again.

Last night it was 10* outside. Unit tripped the roll out switch twice. Now starting to get worried.

What I know.
Unit has an automatic damper that is working as it should.
Unit appears to be running fine when burning. Namely, I don't think I actually have flames rolling out the front of the unit. I can place my hands next to the tray and feel heat, but no sign of burned paint, or other long term heat damage sign.

My initial thoughts as to problem:

I think my issue is a result of ash build up on the heat exchanger. I plan on taking the cover off the unit this afternoon (after the house has heated back up and the unit has cooled).

I suppose the problem could just be the sensor itself. Perhaps when I was using my shop vac around the tray I damaged it?

Any help would be great. I would prefer not to hire a repairman who will give me the old story about needing to replace the entire unit.

Thanks in advance.

 

First things first. You have bigger problems. If the gas boiler is sooted that is a major concern. Why is it sooting? Bad combustion, lack of combustion air? This switch may just be doing what it is supposed to. I am more concerned for you and your family's health due to CO. Get a professional in now! ..................... Is he there yet?
Check for confined space. See link
Calculating Combustion Air

 

Perhaps soot was not the correct term. I cleaned up light white particulates which were not all that much. About 1/4 inch deep in the corners of the bottom of the burner area. When I bought the house the inspector told me the amount of debris was normal for a gas boiler.

I have a co monitor located in the room with the boiler. Room is large and there would appear to be plenty of available combustion air.

The unit pulls a decent draft up the vent. The draft hood is cool to the touch. The front of the burner tray is warm, but does not get crazy hot during the burn cycle.

Flames look nice. Light blue, well defined cones located at the elevation of the burner tubes (they are not over pressured, not yellow tipped.

My heating guy recommends trying a new roll out sensor. Trying to locate one now.

 

OK thank goodness. When I heas gas and soot I panic! Nice to see you are alive and responding ;>)
Yes they can get weak.

 

I will perform the combustion air calculation tonight to verify the amount of air is acceptable.
Any thoughts on the likelyhood the sensor is flakey?

 

I located a replacement part at a local supplier for 8 bucks. Part is interchangeable with utiqa boiler part no UTIAQ 02101.

manufacturer rep wanted $50 and said the shipment didn't meet the minimum. Would have to wait until combined order met minimum. From the parts aquisition standpoint, the system is really staked against the DIYer when it comes to boiler repair.

Anyway, the rep did say the switches tend to get overly sensitive when they get older. Not sure if that is the case or not. Also, I note the switch is nothing more than a surface mount thermostatic switch manufactured by a company named Elmwood. has the following markings 72-235 L310 97/45

I will update when I know if this solved the problem or not.

Installed and running. We shall see if the

 

Any chance that it looks exactly like this?


image courtesy apwapplianceparts.com

 

Is that supposed to be UTICA ?

What is the make / model of your boiler?

I'm sure this is your part but you probably can't buy just 1 ...

AQ02101 CONTROL FIXED TEMP THERMO INT 15L 1639 - Sinclair Supply Ltd.

 

Switch does not look like the photo. Part number listed is accurate. The make of my boiler is lochnivar RBN 090.

Still having roll out switch problems. I had an expert come by to take a look. We learned the following:

Flue is clean, plenty of combustion air. Flame is clean and proper. No cracks or other sign of problems with heat exchanger.

Startup is fine, no actual roll out at ignition.
Not sure what the next step is.

 

Next step is actually already known... replace the roll-out switch.

Of course you need to find one...

Why not call Lochinvar directly and ask them to FedEx one to you because it's an emergency... ask them to wrap it in a promo ball cap too! They just might ya know!

 

Already did. Tripped earlier than the other one.

 

I'm really kinda surprised that switch isn't more readily available... it's used in a bunch of boilers from a bunch of different manufacturers. Utica, Olsen, Columbia, which are all more than likely the same boiler with different brands, but never the less, that switch should be available!

By the way, I believe this is Lochinvar's part number for the rollout switch on your boiler:

HLC2904 ROLLOUT SWITCH

From this parts listing:

http://www.lochinvar.com/_partsfiles/RB-RW.pdf

And this number brings up tons of listings in Google for places to buy.

Patriot Supply - HLC2904

Perhaps the one you were given is not the correct temperature? wrong part number?

 

If you replaced the switch and it is still tripping the only thing it can be is temperature. The boiler has some kind of restriction or gas pressure went up and boiler is over fired. Clock the meter. Find the one cu.ft scale on your gas meter and time it for two revolutions. Make sure the boiler is the only thing running. Not even pilots on anything else.
Here is ways to calculate input.
Checking Gas Appliance Input