Natural gas odor while heater is off - RayPak 156

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I.Robert

I.Robert

0
Jul 18, 2015
30
Hamilton, ON, Canada
Hello,

First of all - huge thanks to TFP as this season has been literally trouble free (at least the pool was) :)

We just installed a pool heater in the spring and it's wonderful!
I have a question about the heater and am wondering if anyone else experiences this...

Occasionally when the heater is off, I can smell a faint odor of natural gas (mercaptan). I can smell it sometimes when I get within a few yards of the heater and then I can't smell it again for about a minute. Even if I get right up to the lines and the unit, I won't smell it unless I wait a while.

The gas guy who installed the line could not detect any leak by the soap method or with his electronic detector.
He said that some of these heaters have valves to the atmosphere and it could purge some gas at times.

I also read on the internet that some people are especially sensitive to mercaptan and can smell it when the leak is actually acceptable and harmless. It seems strange to me that any leak is acceptable.

Thanks for your thoughts or advice!

-Rob
 
Rob,

Doesn't sound right to me. I believe many of the newer heaters have a purge cycle that's part of the start sequence logic. These systems run the air blower through the air intake, burners, and exhaust for a short time to be sure there's no possibility of having explosive level then they turn on the ignite element then open the gas valve. If the system doesn't detect a flame the gas valve shuts. So you could get a little gas in the exhaust during a start cycle. But this wouldn't happen when the unit is not running. I'd have the installer check again. You can't be too careful with gas. The odorant is put in the gas for one reason. To let you know you have a leak. It's done its job and now you should get the installer to find out where the leak is. If he can't find it tell him your not comfortable 'till he makes it stop and escalate with his supervisor if needed. The chance of this being your nose's fault is almost zero.

I hope this helps.

Chris
 
This unit doesn't have a purge cycle as it doesn't have a blower on it. Units that have blower motors will run a purge cycle.

As for the gas smell, is there a regulator somewhere near the heater? Possible that the regulator might be dumping a small amount especially if the diaphragm is having issues. If no regulator, does the supply line come from up out of the ground? Here in FL we use galvanized pipe and lots of times I see where it comes up out of the ground rusts out and every once in a while you might get a whiff of gas. However, usually testing with soapy water tells you there is a small leak.

The electronic sniffers is usually pretty sensitive and can pick up very small amounts usually. If he soap tested all of the connections and still found nothing then I wouldn't know what else to tell you to check.
 
It's possible to get a faint smell coming right off of the burners, or the draft hood especially soon after it shuts down. If you smell gas whenever you enter the room or walk by the heater you have a leak. It doesn't take much gas in the room at all for you to pick up the smell, many times below the lower explosive limit concentration of 5%.

Common leaks on any gas appliance are joints and valves either in the piping, or sometimes internal to the heater (gas valve, pilot connections, test port plug, etc).

As mentioned before, if there is a regulator in line somewhere nearby, it has a vent on it, and it can puff a tiny amount of gas occasionally. Usually in a residential situation you won't have a separate regulator near the appliance as it's built into the unit's gas valve. The main regulator will be at the meter. If there is a constant odor from that, though, it has failed and needs replaced.

If you can smell it, a decent electronic sniffer in the right hands should be able to find it. I have pinpointed many a gas leak with just my nose, then verified with soap bubbles, or a lighter. I'm not going to officially recommend that, though, lol...
 
Thanks everyone for the great replies!

The line is yellow gastite to cast iron, with brass couplings.

There is no external regulator.

Could the internal regulator occasionally discharge normally? It's definitely not a constant leak.

Also I think it is more than a minute or two between discharges. I took a sniff last night.

-Rob
 
Anywhere nearby the appliance but it seems stronger if I get right up to the area where the line enters it.

The installer had the cover off and I watched as he soaped every connection inside and out. Of course at that time there was no odor for him to smell :rolleyes:

-Rob
 
Rob,

You've got an expert on this thread that clearly knows more than I do about your specific unit. So I'll stand aside as he helps you. I'm definitely not an expert on your unit. I will say though that I've worked in the gas production industry for 40 years. Most of the time when people have problems like you describe it turns out to be a faulty part or fitting that is leaking such a minor amount of gas it's very hard to detect until it gets worse and then it gets fixed... no big deal. However there are those cases where it gets bad quickly and unexpectedly and somebody gets hurt. I've led fatal accident investigations several times and it's not pretty. So please don't write this off until you absolutely, positively are certain what's causing it and it is fixed.

Best regards,

Chris
 
I appreciate all of the replies!
It was really helpful to know that this appliance should not purge.

I finally got my gas guy to send someone to check everything.
It turns out that one of the gastite fittings just needed to be a little tighter. It took over a minute to build a soap bubble. The tech said that he was surprised I could even smell that outside. Not a dangerous leak at that stage, but a leak is a leak.

Happy to get to the bottom of it!

-Rob

P.S. I forgot to mention that I also called Rheem to understand the warranty. They need a gas tech to document that the leak is internal to the unit, before they will authorize any work. They also said that the test needs to involve a manometer at the inlet and after the manifold.
 

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I.Robert said:
I appreciate all of the replies!
It was really helpful to know that this appliance should not purge.

I finally got my gas guy to send someone to check everything.
It turns out that one of the gastite fittings just needed to be a little tighter. It took over a minute to build a soap bubble. The tech said that he was surprised I could even smell that outside. Not a dangerous leak at that stage, but a leak is a leak.

Happy to get to the bottom of it!

-Rob

P.S. I forgot to mention that I also called Rheem to understand the warranty. They need a gas tech to document that the leak is internal to the unit, before they will authorize any work. They also said that the test needs to involve a manometer at the inlet and after the manifold.
Click to expand...
Great Job! So happy that persistence paid off for you.

Sent from my SM-N900V using Tapatalk
 
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