Heater stops igniting after rain

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andyoi630

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Aug 30, 2013
150
Maryland
Hey everyone,

After a month or so of initial troubles with getting the right gas supply to my new Jandy LXi heater (plumbers kept undersizing it), everything worked great. That is, until it rains.

Every time we get a decent rain, the heater won't ignite for several days, no matter how many times you try. After a few days it will start up like normal.

Makes me think water is somehow getting to where it shouldn't, but aren't these designed to be outside without a cover? I'd be hesitant to build any sort of overhang/covering because of how hot the exhaust heat is on this.

Any ideas? Thanks!
 
No there shouldn't be anything above the heater as per the manual.

Sounds like you have a new heater which should be under warranty so I would get them involved. You can simulate the rain obviously with a garden hose. You are correct that these are designed to be out in the rain/elements so I am not sure what you have going on with it. The area where the ignitor is located is enclosed pretty well.
 
Kind of what I figured.

Can you think of anything on the gas supply side that could be causing the problem? I just want to make sure I know it's a heater issue before they come out and visit and blame someone else. Doesn't really look like water could get into the regulators though, they are vented with a tube that points downwards to keep moisture out.
 
ps0303 said:
You have some sort of electrical issue. Gas supply wouldn't have anything to do with it. Is there a regulator for the gas by the heater?
Click to expand...

Yes there is a regulator right by the heater to drop from 2 pound service.

I'm not totally sold on it being electrical. I say that because - ignitor lights, I hear gas valve click and smell gas, but no flame.

It is the EXACT same behavior I saw when they first installed the heater with an undersized gas line that was starving it. They upsized the line, and in dry weather works great. (1" x 75 ft, 3/4" x 40 ft, 2 psi supply).
 
I guess I should have asked if you were hearing all of that and the smell of gas. I was under the impression it wasn't doing anything. Still though the fact that it only happens when it rains is interesting. Is there a vent link off on the regulator?
 
Does it have a click type igniter like a gas stove, or the coil type element like a gas oven? If it's the element style, like I assume it probably is, I have no idea what it could be. If it actually uses a spark, maybe something is getting wet. I know my gas stove won't light if my wife decides to clean the burner pieces in water because they aren't making a good connection since they are wet. Light it with a lighter, and all the water evaporates, and it works fine again. May be something similar with your heater. Could be a ground wire to the ignition box is getting wet.


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I'm not a gas plumbing expert but my heater has a gas line that has a pipe with a T and a vertical piece of pipe about 8 inches lower than the inlet to collect water and debris. Not sure if you may be getting water in your line.
 

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That regulator is for a stove, not for a heater. How many BTU's is the heater? This is natural gas?

If you had water in the line it would never light. It would clog the gas valve and then you would need to replace it.

Also, update your profile to include your location.
 
If that is a maxitrol 325-AL, it only has a capacity of 300K BTU. It's not the regulator you should have on a 400K BTU heater.

Yes the line should have a drip leg on it before it goes into the heater. It sort of looks like in your picture there is a drip leg between the regulator and shut off valve, but it's upside down. I can't tell what the fitting is just after the regulator. If it is getting water in the line somehow it would be locking up the gas valve and it wouldn't work at all.
 
Sorry I could have had it wrong, might be a 425-AL, I remember looking it up before and seeing 425 capacity. I will check tomorrow and upload a better picture.

That isn't a drip leg, that's the leg going to the heater, there's another leg there that goes back underground to go to a series of torches and fire pit.

How would water be getting into the gas line?
 
I have a totally different gas line for my gas fire pit from heater. When I don't use the fire pit for a while I can hear water gargling when I turn it on. I don't think that line has a drip leg any where that I know of. The only way I can think of is water can get into the gas line thru the fire pits burners its self.
 
You need to take diagnostic steps in order to find the solution, or else you'll guess by parts changing.
Wait until the issue recurs, or like PS0303 suggested simulate the rain fall with a water hose.

When the problem is present I would test:
Igniter voltage
Igniter alignment
Igniter warm up timing ~45 sec
The igniter must reach ~1163°F to combust the natural gas. If any of the three are incorrect, the fuel may not ignite.

High RH can inhibit the combustion as well. An increase in moisture will lower excess air or O2, reducing air density and starving the system for combustion air. Other factors that could starve the system would be elevation, temperature, and high wind.
So it would benefit to have the unit placed on a fast drying well drained surface, guarded from wind, and set up for proper elevation.

I would also check the manifold pressure at the gas valve. Too high or low gas pressure could cause ignition failure.
Are you in a high altitude area? Steps would need to be taken to adjust the air fuel ratio.
I would also check the orifices to ensure the proper set up. If you're below 2000', it's likely no changes will be in order.

If you can't test the pressure at the gas valve, you can also get a measurement by clocking the main gas meter.
To test the heater input set-up, turn all other appliances to pilot, then turn on the pool heater and note the reading from the meter, and compare with install manual.

Here's a link to help with the procedure. http://hvac.amickracing.com/Formulas and Calculations/Clocking a Gas Meter.pdf
Most nat gas heating btu values are 1020-1050/cuft.

So, if your gas company supplies 1050 btu/cuft, and you clock the meter at ~6.35cuft/min, then you have ~400,000/hour input.

On a side note, the T fitting downstream of the regulator (shown in the picture) only needs to serve as a pressure test tap, not a drip/sediment trap. There should be another upstream the regulator to serve as both pressure test tap and drip/sediment trap. There should also be one as close as possible to the unit connection.
 
So I did some more looking at things as the problem showed up again.

Regulator is a 325-5AL (says it's good for 425 CFH).

I opened up the gas union closest to the heater after shutting nearest gas valve. No real signs of water in there.

What I did notice however, was that if I opened the gas valve while the union was open, there was about a 5 second period with nothing coming out. Then the regulator would open up and gas would rush out.

Previously when I looked at this, I remember gas always rushing out, not a delay. Does anything sound strange here?

Called the gas tech to see what he said, waiting on a call back.
 
Sounds like a problem with the regulator. So after the gas started flowing did it seem constant? I would have the tech check the pressure at the regulator. I wonder of the vent line on the regulator has water in it. That can sometimes cause strange issues. I usually disconnect and blow in to it to see if there is water in it. I see water in the vent line on LP and never seen it on natural. Heck usually the natural isn't vented because it doesn't pool around the ground like LP does as natural is quicker to dissipate.

This is the regulator that you have? http://www.supplyhouse.com/Maxitrol-325-5AL-1-1-Line-Regulator-300-000-BTU-10701000-p
Says it good up to 300K BTU.
 

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