THERMOCOUPLE ??

D COFFEY

I HAVE A HYDROTHERM NAT-GAS BOILER EVERY 6-8 MO. I HAVE TO REPLACE THE THERMOCOUPLE.

Unknown

Thermocouples

First of all do not post with caps, it is considered shouting, thanks.

Typically whe you are changing thermocouples frequently it is one of the following:

1. The pilot may be adjusted to sharp and is burning the tip of the thermocouple. The tip should be a dull red not cherry red. The pilot should be a soft blue flame hitting the upper 1/2" to 3/8" of the t'couple.

2. If the lead of the t'couple is discolored or scorched it is a sign of combustion problem.

3. Make sure you have sufficient air for combustion.

4. Make sure the boiler is not overgassed.

5. What make of t'couples are you using?

6. Some boilers have a tendency to run very hot during extreme cold temperatures as they are running longer or cycling more often.

7. What are your millivolt readings open circuit, closed circuit, closed circuit with burner running, drop out?

8. How old is this Hydrotherm boiler?

9. Are there any contaminants in the vicinty of the boiler. Is the t'couple discolored, green or red stuff on t'couple.

Hope this helps, if you need further assistance I have a Troubleshooting Guide available on thermocouples.

D COFFEY

?

I have checked the inlet gas is 8"wc and 2.3"wc to burner.
I tried to adjust the piolt setting and found it made little to no change. The boiler is about 4-5 years old and this all started about 3years ago. I have used Honeywell universal thermocouples for replacements.I think the pilot is to hot and burning out the tip of the thermocouples changed gas valves and still have a large pilot with no adjustment?

Maurice Pickett

Thermocouples

Try using a Husky Thermocouple by Baso (Johnson Controls) and you may want to consider reducing the pilot orifice size without compromising the ignition.

Unknown

Pilot gas is unregulated

it is on line pressure and can be adjusted by the pilot adjustment screw on the gas valve. If the screw does not adjust the pilot spray a little WD 40 into the hole and then try screwing it down. What make of gas valve is it and why did you change it?

The outlet pressure is too low it should be whatever the rating plate on the boiler calls for usually 3.5" W.C.

I would try a Johnson controls T'couple next time nickel plated number K16RA.

[Deleted User]

stop wasting money

on those honeywell universals.Call your local supply house and find a Johnson controls nickle plated high temp. thermocouple.It's a heavy duty model an it'll hold up to all that fire!I think the people at hydrotherm will give you a part no. if you need one.Mestek is the name of the parent company,try this phone no.(413)568-9571.Good luck!

Unknown

I would not change

the pilot orifice. It was sized by the manufacturer for proper ignition. The answer is to adjust the flame with the pilot adjustment screw. Make sure it is the pilot adjustment srew you are turning and not the regulator adjustment screw. The screw is located near the pilot tubing outlet on most valves.

BillW@honeywell

t'couples

You also could try using our heavy duty Q340 series, you probably are using the Q390 basic units.

[Deleted User]

thermocouples

I don,t want to give the impression that I have anything against honeywell t'couples,but that seems to be all that any one will stock at their local hardware and big boxes and they just don't suit EVERY application.

[Deleted User]

Dennis - Reliable Services

Why not convert

to electronic ignition, less hastles around.

Boilerpro

Ahh, But they cause other problems

like rusty boiler heat exchangers in humid areas. My standing pilot boilers tyically have no rust in the burner tray after two to three heating seasons...Electronic ignition units need to be cleaned every year and of course that rust on the heat exchanger is reducing firing efficiency too. Standing pilots probably save fuel over electronic ignition by keeping heated surfaces nice and clean.

Boilerpro

Unknown

You got that right

I love that old pilot sitting in their 24/7 keeping everything dry.

ScottMP

But is it efficient ?

I agree with all you say about the standing pilots good points

But to play devels advocate, is it a prudent us of a finite fuel ?

I know the difference per boiler is minimual. But the combined effect on ALL gas appliances would substantil.

I believe we need to help do our part and inform our customers of availabilty of enviromentally friendly equipment.

And there is my two cents.

Scott

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Boilerpro

That was my main point...

I bet that clean heat exchanger is going to use alot less fuel than a rusty one. The savings in fuel due to better heat exchanger efficiency probably far outweighs the extra fuel the pilot uses. A standing pilot equipped gas boiler is probably the far more environmentally friendly choice due to lower fuel usage over its life. AFUEs only apply to new clean boilers. Once a standing pilot boiler sees a few years use, I bet its heat exchanger is more efficient than one with electronic ignition due to the rust build up on the electronics heat excchanger and the flakes getting into the burners between cleanings. A couple more cents.

Boilerpro

Unknown

My nickels worth

for what it is worth if you believe the scientist and gurus of the gas industry, THEY tell us that there are enough gas reserves with the present rate of growth and predicted discovery of more gas. are you ready for this....

Too last another 500 years!!! HMMMM I really wonder about that.

If that is the case light up those pilots.