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Rick, General Contractor
Category: Pool and Spa
Satisfied Customers: 21532
Experience:  Licensed construction supervisor with 35+ yrs. experience.
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I'm Kevin. I have a one year old Hayward H150 pool heater

Customer Question

Hi: I'm Kevin. I have a one year old Hayward H150 pool heater (above ground, 24 ft.round). tried to start last week and in process, messed with things I probably shouldn't have. turns out the inside gas valve was off. when I turned it on, the pilot lit right away and when the pump was on, heater switch on and thermostat set hight, the main heater burners ignited but both the burners and the pilot went out. I've repeated this several times.
What I messed with was two things. I undid and replaced a phillips head screw near the stamped PILOT ADJ on the combination gas valve. this appeared to have a crumbling O ring at the top just under the screw head. The other thing I did was undid the flat head screw on the upper left of the combination gas valve and found a white plastic phillips head screw that I tried turning in and out a bit then returned it to what I thought was the original position and replaced the flat head cover.
Your thoughts on what might be the situation now would be appreciated.
Submitted: 2 years ago.
Category: Pool and Spa
Expert:  Rick replied 2 years ago.
So the burners lit then went out a short time later? Is this electronic ignition or is the pilot lit all the time?
Customer: replied 2 years ago.
not sure if you got your response; the website keeps redirecting me back to the beginning. I paid a $23 deposit and received a question and was presented with a new agreement for more money. What give?
Customer: replied 2 years ago.
yes, pilot and burners. a few minutes later the burners went out and then I found the pilot out as well. I've repeated relighting and starting and the sequence repeats.
Expert:  Rick replied 2 years ago.
I have no idea what you see or what the site does for marketing. I only answer your questions related to the issue that you mention in this thread. If you have payment related questions or complaints about the site's marketing please contact customer service at didn't answer my question re: pilot lit all the time or electronic ignition.
Customer: replied 2 years ago.
pilot should be lit all the time. Millivolt system.
Expert:  Rick replied 2 years ago.
Ok, one possibility is that you have a stray flame impinging on the thermopile (the flame sensor in the pilot flame). The thermopile generates all the power to operate the gas valve. It does so by maintaining a cold junction which means keeping the bottom 2/3's to 3/4's of the thermopile out of and away from any flame. So you might check to be sure the burners are clean and no stray rust flakes or debris is diverting a flame at the thermopile's base. Beyond that, if that doesn't seem to be the case you'll need a multi-meter that can read DC milivolts.
Customer: replied 2 years ago.
can't easily see or reach the thermopile - any tricks?
Heater is just under 1 year old so rust doesn't seem likely (don't see any rust). `
I have an analog multimeter that has a 0-2.5V so I can read in 100 milivolt DC increments.
Expert:  Rick replied 2 years ago.
Rust may no be an issue but debris, particularly after a seasonal shut down, is very possible. You need a digital meter. You'll probably have to pull out the burners to check.
Customer: replied 2 years ago.
if I can get a digital, where do I check (terminal labels, if possible) and under what conditions? In my original email, I mentioned that I unscrewed the pressure regulator cap and moved the plastic phillips head screw back and forth a few times before I found the gas valve was off at the house. Could this have a role in my problem and how should that pressure be set? what is the typical position of that white plastic screw (mostly up/ or down , 1/2 way)?
Expert:  Rick replied 2 years ago.
Yes messing with the gas pressure adjustments could impact this problem. There is no "typical position". Those adjustments should only be set with a gas pressure gauge (reading in inches of water column, WC) on the manifold so manifold pressure can be set properly. Too much pressure could cause a burner flame to impinge on the thermopile's cold junction. The first thing to check/monitor is the voltage across THPP & PP terminals on the gas valve. If the reading drops below 350 mV with the pilot lit (main burner lit or not) then the output from the thermopile is inadequate. It's possible the pilot flame is too small and that could affect thermopile output so messing with the pilot adjustment screw could impact this. We just eyeball pilot flame size which should be ~1" long to be healthy. A weak pilot could also explain why the pilot goes out when the main burner goes out. The main burner could go out if one of the devices in the limit circuit open. You can test for continuity across TH & THPP for this. If you lose continuity you need to follow the black leads from the gas valve to each device (also includes the pool stat and system switch) to see which one is open. Here is a link to the manual in case you don't have one
Customer: replied 2 years ago.
Thanks, Rick. which direction (cw or ccw) to adjust pilot flame up? I'll be able to check gas pressure tomorrow with a pressure gauge to see if that's set incorrectly. Natural gas, so 3.5" H2O is the optimal pressure according to the manual.
Expert:  Rick replied 2 years ago.
You're welcome. Clockwise should increase the pilot flame.