Boiler Standing pilot thermocouple fails quickly

Ed Lentz_2

I have a Crown boiler (Model # escapes me at the moment) It is about 15 years old. It has heated my hot water system well, until.... About once a year I need to change the thermocouple in it. I buy Honeywell devices, I think they are good. What would make these fail so often? Poor design, bad devices. the original one probably lasted 10 years. Is there a solution?

Thanks

HomerJSmith

You probably running it too hot or at the wrong flame position. The gas valve has an adjustment for the pilot flame intensity.

Ed Lentz_2

Thanks I will check it out

STEAM DOCTOR

There is probably too much heat under the boiler. Causes the two metals in the thermocouple to weld together. Might be partially  blocked chimney or boiler sections. Maybe a draft issue.

Ed Lentz_2

STEAM DOCTOR said:

There is probably too much heat under the boiler. Causes the two metals in the thermocouple to weld together. Might be partially  blocked chimney or boiler sections. Maybe a draft issue.

Now that is more serious, I can easily check the draft situation.

STEAM DOCTOR

In my travels, it's almost always the chimney 

Ed Lentz_2

It will be easy to check. The vent pipe is about 4ft long to a masonry chimney. I have a cleanout door at the bottom of it. There is an automatic draft valve in the vent pipe. It used to open and shut but I think it is open all the time now.

Steamhead

Several years ago, I had the same issue on a Peerless (61 or 62 series?) boiler in a large house. Honeywell thermocouples were failing every year. This thing had two pilots with a thermocouple on one, and the other was spark ignition.

So I called Peerless tech support and they said basically "yeah, we know. Switch to Johnson Controls thermocouples and you won't have a problem". Long story short, they were right.

Johnson has spun-off their gas controls and they are now sold under their original name- BASO. @EDLentz_2 , try this and see if it helps.

Incidentally- BASO is an acronym for "Baltimore Automatic Shut Off". Apparently it was pioneered here, but the manufacturing was done in Milwaukee. See:

https://www.baso.com/gas-control-products-manufacturer

Ed Lentz_2

I will look up Baso and get one of those. I definately have been buying Honeywell. Also check out all the other suggestions.

Is there a way to convert this to spark ignition or is it to old?

Steamhead

Ed Lentz_2 said:

Is there a way to convert this to spark ignition or is it to old?

Yes. Honeywell makes an upgrade kit, but it's not a DIY job. Where are you located?

STEAM DOCTOR

Agree. The Johnson/Basco thermocouples are top of the line. They are available on SupplyHouse.  My go to thermocouple. Fyi, all of my knowledge on this matter, is courtesy of @Tim McElwain.

mattmia2

I hope Tim's doing ok, we haven't heard much from him in a while.

JUGHNE

IIRC, from another web site, someone has at the bottom of their postings:

"Honeywell.....you can buy better....but you can't pay more!"

Ed Lentz_2

I'm in Midland Michigan. There is a Baso reseller about 30 minutes from me in Saginaw.  What would updating to a spark ignition cost installed.  Ball park

Ed Lentz_2

I checked out my chimney.  Totally clear.  Looks like I stocked up on thermocouples. I have 3 24" Resideo. Which are Honeywell I believe.  My boiler is a crown AW109

Steamhead

Ed Lentz_2 said:

I'm in Midland Michigan. There is a Baso reseller about 30 minutes from me in Saginaw.  What would updating to a spark ignition cost installed.  Ball park

We don't discuss pricing on this site. See:

https://heatinghelp.com/forum-user-manual

I believe @GGross is in Michigan, if you want to get in touch with him.

Ed Lentz_2

Point taken.  I found the kit at Supply house.  I might just get the thermocouple that fits the budget better.

SteamingatMohawk

I have a Smith boiler with a standing pilot (not sure if that is relevant) and experienced the same problem. About once a year the Honeywell thermocouple would fail. Eventually I looked in the boiler manual and it calls out a K16R in either 30 or 36 " length. I bought one at my local Smith dealer and it's a BASO. Since then, I don't recall replacing any thermocouples, but keep a spare on hand as the boiler is in a rental property.

Steamhead

Ed Lentz_2 said:

Point taken.  I found the kit at Supply house.  I might just get the thermocouple that fits the budget better.

You don't want to install the upgrade kit yourself. If you go that way, get a pro to do it.

SteamingatMohawk

I looked in my records and it was bought in 2019.

SteamingatMohawk

But I don't have information whether it is a replacement or a spare.

Ed Lentz_2

Steamhead said:

Ed Lentz_2 said:

Point taken.  I found the kit at Supply house.  I might just get the thermocouple that fits the budget better.

You don't want to install the upgrade kit yourself. If you go that way, get a pro to do it.

No worries there I know my limits. I installed the whole thing myself, but I had a boiler installer lay it out and had it inspected. Replacing the gas valve, not something I want to do.

Ed Lentz_2

I ordered a Baso thermocouple and will install it when it gets here. Hopefully it will last a long time.

Bob Harper

It may not be the thermocouple. You can test it for proper operation, but you also need to rule out low inlet gas pressure and proper venting. Improper venting can result in spilling CO2 (maybe some CO as well) but the CO2 will displace oxygen near the floor level snuffing out the pilot.

Tim McElwain

Johnson Controls several years ago sold out their gas division and it is now called BASO Gas Controls LLC. I recommend the Husky thermocouple. Once it is installed make sure to take some millivolt readings and also I would do a combustion test on the equipment. The Husky may not fit your pilot but BASO makes a similar thermocouple that will fit.

Ed Lentz_2

I purchased the universal thermocouple. The manual said I needed a 30mv model and that is what I got. I probably should have a professional do those tests everyone are talking about. Not may boiler guys around here.

Steamhead

Ed Lentz_2 said:

....Not may boiler guys around here.

ISTR @GGross is somewhere in Michigan...................

GGross

RP Carder Mechanical is in that area, I haven't dealt much with them in a while as they are out of my service range but they always did nice work, they install and service boilers

Ed Lentz_2

Holy crap! RP Carder is located within 100 feet ot the house I grew up in. It all has changed in that block, but I had good friends that lived in that address. Never even heard of them either, have lived in Midland all my life. Small World

Steamhead

@GGross @edlentz_2 You might suggest they get on this site's Find a Contractor page, as my company did. This is not the first time a Michigander has come on here looking for help.

Ed Lentz_2

I will ceretainly do that. Thanks

Ed Lentz_2

@GGross Where are you located? Just wondering

mattmia2

Steamhead said:

@GGross @edlentz_2 You might suggest they get on this site's Find a Contractor page, as my company did. This is not the first time a Michigander has come on here looking for help.

Midland isn't even near where most of the population is.

Ed Lentz_2

mattmia2 said:

Steamhead said:

@GGross @edlentz_2 You might suggest they get on this site's Find a Contractor page, as my company did. This is not the first time a Michigander has come on here looking for help.

Midland isn't even near where most of the population is.

Midland isn't THAT small. Just far enough from the big city problems. But far enough away to be about 10 years behind ( For some things that isn't all bad.