LP Heater No longer firing after gas pressure adjustment

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brettnem

0
Jul 31, 2017
9
Austin,Tx
Hello All,
I have a Jandy LXi LP heater that has been working *great* for many years. I had the gas service company come out for unrelated reasons and they checked all my appliances. When they checked the pool heater, they noticed it was connected behind a 2psi regulator. The heater specifically says it's rated for 11WC to 14WC. So they red-tagged it and said I couldn't use it anymore until I put a proper regulator on it. Keep in mind, it's been working just great for years. :/

Fast forward to today. Had the gas company come out and put that regulator on. I watched him test the pressure, initially set to about 12WC. The heater wouldn't fire up so I had him up the pressure to 14WC. Still won't fire.

Everything sounds normal. When I start it up, I hear the blower for 20-45 seconds, then I hear the clicky sound of it trying to ignite (gas valve?), but no woosh. It tries I think 3 times before the blower shuts off and it goes into ignition fault. (Also get the 3 flashes internally on the unit).

The gas guy told me that there is likely air in the line and because of the density of gas it could take a few cycles to get it all out. I've cycled it about 5-6 times already. Do I need to keep cycling it? Could it still be air? Or could it be something else? Should I expect to need to adjust anything else going from 2PSI to 14WC? BTW, 2PSI = 55.415WC. :oops:

Thanks!
-Brett
 
Is your heater Natural Gas or Propane?

Was the heater installed by a prior owner or do you know who installed it?

My WAG is the installer may have made some internal gas regulator or orifice adjustments to get it to work with such high gas pressure. With the new gas regulator the hack needs to be undone.
 
So here's the setup:

1. 500 Gallon in-ground tank.
2. 10 ft run to a 2psi regulator
3. 25 ft run from 2psi regulator to hot water heater. All piping looks to be 1in metal pipe
4. There was a simple, manual gas shutoff about 1-4 inches outside of the heater.
It worked great like that.

He basically cut the line right outside of the heater, placed the regular right there and then attached a vent to the regulator and plumbed it out about 8 feet away; which he said was to code (don't want an emergency gas venting to occur right next to the equipment).

I had him watch me attempt to fire it up a bunch of times and fail. He told me he sees that a lot and that usually it's air in the line. He offered to bleed the line using the.. I don't really know the parts of the regulator, but there is a smaller port where you attach a meter to measure the pressure. He opened that up completely (removed the screw and I heard gas whizzing out). We let that wizz out for maybe a couple of minutes.. He repeatedly (against *my* better judgement...) kinda sniffed the venting to see if it was gas or air. I could definitely smell gas. We did this actually twice.

he did mention that between that vent and the actual valve inside the heater there is about 2-3 feet of pipe (most of which is behind the front panel). And that there is likely air in that section and there wasn't an easy way to bleed that. He did also admit that he just doesn't work on pool heaters; so he could be missing something easy.

So I'm not sure if I just keep cycling it like a fool, or if something else is wrong?! Is there something I can troubleshoot myself? Why/How could it have been hooked up like it was before? Seems terribly dangerous being 4x the max pressure? Why would it have worked without the heater running way too lean? Would I need to adjust the burner throat because of the different volume?

Right now what I'm thinking is that whoever installed this (before my time) adjusted the heater to run at that concentration.. which is way out of adjustment for a proper air/gas mixture. Not sure what to do next.

And yes, the valves are open. Both the external shut off and the one on the inside. I've manually turned them off and back on to be sure no one did something stupid and forgot.

FWIW, it's also been *really cold* for Texas the last few days.. 20-30 degF. Not sure if that affects any of this..

Ideas?

Thanks!!
-Brett
 
ajw22 said:
Is your heater Natural Gas or Propane?
My WAG is the installer may have made some internal gas regulator or orifice adjustments to get it to work with such high gas pressure. With the new gas regulator the hack needs to be undone.
Click to expand...

This is what I'm thinking too.. But I'm not sure what gets adjusted to do something like that and how to *properly* undo it..
 
I would let it cycle for a while and see if the line has air in it. the pilot tubes are tiny it can take a while to clear out. I usually open up the line like he did until gas appears then open the pilot line and clear it. if its a spark ignition unit you cant do that you gotta just let it go til it fires unless you jump the solenoid to the pilot valve. I dont know who installed this heater but 2psi is alot to a standard gas valve, its likely damaged the diaphram/spring at that pressure. you say it worked fine but I bet a trained LP guy would have noticed the flame being very off from normal color and burn. LP runs on higher pressure than natural gas, you see an upsized regulator on NG when the line is undersized and you need more volume to feed the appliance. with propane in your scenario they probably installed the heater and it fired and they let it rip. almost no-one these days owns a manometer and knows how to setup a gas valve properly for LP or NG unless they are a PRO
 

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