Leaking gas valve on 4yr old Triangle Tube

wrxz24

Hi all, I just had my Triangle Tube 110 solo boiler serviced and the tech noticed the smell and put a device that detects gas up inside the intake and it beeped pretty fast. He believes that the gas valve is bad and needs to be replaced. Are gas valves prone to fail in only 4years of service? Things to check before replacing? thanks in advance

Leon82

Did he double-check the tightness of the port for probing the gas pressure?

wrxz24

Not sure. What is that exactly? He cleaned the heat exchanger, the igniter and did a combustion check.
numbers:
O2ref 3.0%
CO2 max 13.8%
104.5 deg temp stack
11.36% CO2
95% eff gross
105 ppmCO
3.7% Oxyegen
19.6% excess air
61.7 ambient temp

lchmb

Did he do a pressure test to check for a drop in pressure when the unit was off? If there is a drop in pressure you have an issue. If not I would have him contact tech support, I suspect it may just be the fact it's where the air/gas mixing occures and when the unit shut's off a slight odor is present. I would also have him lower your ppmco. Triangle tube wants that number 100 or less...

Ironman

13.8% CO2? That's whay too rich. It should be between 8.8% - 10.5% on natural gas.

That may be what set the detector off: residual unburned fuel in the flue.

kcopp

I'm guessing that's LP...

Zman

The unions on those gas valves often leak.
Try snugging them up and see if the problem goes away.

I agree that everything about the combustion tests indicates that the boiler is running rich.

The analyzer only measures O2 and CO, the rest is calculated by the machine.
The O2 number looks fine. The CO is high. Should have been leaned out a bit.
Not sure why he left it with the CO above 100...

wrxz24

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He said he would do another combustion test after putting in the new gas valve. As far as the propane, you can smell it when you put your nose up close to the intake.

wrxz24

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Yes sorry, it's propane

wrxz24

null
You can only smell propane if you put your nose up to the opening of the intake, I too thought it was just residual smell from the burn but it sure smells like a leak now. I also noticed a black residue on the elbow of the intake.
So is it possible to have that smell on a rich running boiler or is it running rich due to a faulty valve? In other words, will adjusting the CO2 in spec make the smell go away? Thanks in advance.

wrxz24

The residue pic. The boiler was on standby and cold and you can smell propane but only from intake.

rick in Alaska

Not sure about the residue, but very well could be you are pulling combustion gasses back in through the intake. I would check the termination to make sure it can't happen.
Not sure about the gas smell in the intake, but something tells me a new gas valve will still give the same results.
Rick

wrxz24

rick in Alaska said:

Not sure about the residue, but very well could be you are pulling combustion gasses back in through the intake. I would check the termination to make sure it can't happen.
Not sure about the gas smell in the intake, but something tells me a new gas valve will still give the same results.
Rick

The funny thing is, is that after the boiler has been in standby with no combustion for a few hrs, you can still smell the gas when you put your nose close to the intake. I took the intake off and there is a gas smell coming from the opening it connects to.

Tim McElwain

What is the gas pressure after the second stage regulator? It should be around 10" W.C. if it has been increased this could cause a problem with the gas valve especially on a negative pressure type gas valve.

wrxz24

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Not sure but the first stage was 7.5" according to our new gas company that did an appliance and tank check.

delta T

I just serviced a TT the other day that has been kicking intermittent E-02, never could reproduce it on site, changed the igniter, as it was 6 years old and somewhat corroded, checked combustion, all seemed well. Then it did it again. Decided it was time to do some digging, pulled the burner checked the venting, loose wires etc, etc...Finally, I found the venturi to be badly deteriorated. Checked the flue termination to find the concentric cap was not quite seated properly, allowing a small amount of exhaust to enter the intake air, which in turn deteriorated the venturi.

The reason I mention this, is that the detriorated plastic has a very potent odor to it. Not sure if it would set off a combustible gas detector or not, but maybe @Tim McElwain could shed some light on that?

Just a thought, something else to check.

7.5" is too low for LP, you need 10" as Tim says.

Tim McElwain

Your first stage regulator should have usually 10 pounds pressure, then reduced down to 10" W.C. at the second stage regulator.

Gas detectors can be sensitive to a lot of things, I have seen them react with pipe dope.