Georgenmel --- New member as of July 27,2015 -Thanks for making pool help available !

[georgenmel]

- Could use some help with our Laars Lite - LG400P - propane pool heater ! - Pilot lite will not stay lit when valve is released. I have already replaced the main gas valve, and the pilot light & generator assy. - Still the same thing - Pilot light stays lit as long as I keep the valve down - when I release it, light goes out. I've checked continuity on fireman switch, fusible link, pressure switch, & pilot generator - all good - Can the limit switches or redundant switch cause this problem? Also, can I test these by jumping the terminals of the switches to complete the circuit?-
- Any help sure would be appreciated!!! -- Don't want to keep throwing parts at it - Also, I replaced the main switch & temp. control last year with new unit -- Thanks again for any help!

 

[BoDarville]

Welcome to TFP!

Some possibilities:

1. Thermocouple is bad
2. Pilot flame is above the thermocouple resulting in it not getting warm enough to hold the gas valve open.
3. Pilot line or orifice may be clogged. Spiders like to build webs in the pilot and burner tubes.
4. Venting downdraft extinguishes pilot flame

 

[georgenmel]

Thanks for getting back to me - The pilot generator (or thermocouple) is new & part of the new pilot assy( pilot flame housing, gas line & orifice-- all new) - which leads me to believe the old parts were still good - The pilot has a good flame as long as the gas valve knob is held down - once I release it, even after several minutes, the flame goes out. - Do the limit, pressure, & redundant switches have anything to do with the pilot staying lit, or do they just apply to burner operation once the valve is turned on?? -

 

[BoDarville]

I'm more inclined to think that either a draft is blowing out the pilot flame, the gas valve is stuck in the closed position, or the electric current generated by the flame touching the thermocouple is either insufficient or is not getting to (energizing) the gas valve to stay open. When you hold the gas valve knob down, you are manually holding it open. When the thermocouple heats up, a small amount of electric current is being made. That current is what keeps the pilot safety valve on the gas valve open. This usually takes about 30 seconds or so. When you release the knob, the electric current is designed to hold the gas valve open.