Time for a new gas valve, or time for a new heater?

[glutton4punishment]

I've been working on opening our pool for the first time, and for the most part, it went... swimmingly.

The problem I'm having is that my Teledyne Laars Lite Natural gas heater (possibly from 1982?!) will not fire up. It worked last season. The pilot lights and stays lit. I have replaced the pressure switch (old one was leaking from bottom) and the thermocouple/generator. The new generator puts out about 400 millivolts at best when the pilot is on, but the average is closer to 330. I believe I need at least 500 for the burners to ignite?

Based on everything I've read, on this sites and others, I believe I need a new gas valve. I've found one on Ebay for $220, one on Amazon for $300... retail is about $440.

My question: Should I risk throwing away $200-$300 on such an old heater, hoping it's the gas valve, or is it time to accept defeat and buy a new heater? One reason I'm hesitant to buy a new heater is that I can't find many good reviews on anything, making me leery of anything new! Also, the rest of the heater seems fine... the burner looks fairly new - I'm guessing the previous owner replaced it recently.

Thank you in advance. This site has already been very helpful, and I've tried to hold off on posting 'til I ran out of answers from searching.

 

[ps0303]

It could fire at 330 but it should be much closer to 400. Have you connected the volt meter to the valve and then turn the switch on to see what it reads under a load? Check thru the safety loop and all of the components to see if maybe one of them is bad.

If you consider a new unit, consider Raypak. I install 80-90 per year and they have the fewest problems of all the units out there. It is a very basic unit very similar to your current unit. No extra boards or blower motor. Very easy to repair as well.

 

[glutton4punishment]

Thanks for the reply. I noticed a lot of people on this board like Raypak - I started looking at them last night and I think that's the way I would go.

Even when I got it above 400, it would not fire. I have tested the valve under load (I assume by "under load" you mean when I'm attempting to light the burner) - the number drops significantly.

I will head back out there this morning and run through the components I haven't replaced. Since you're telling me it should fire at 400, I'm wondering if the thermostat could be the culprit... time for more testing.

Thank you!

 

[glutton4punishment]

I just finished checking the continuity of all parts and wires, as suggested. The only part that did not have continuity was whatever connects to the board with two black wires - I'm assuming this is the thermostat. I bypassed these wires by making a jumper. Burner still wouldn't fire. Then I added a torch to the pilot flame to increase the millivolts closer to 500 - I reached about 470, which dropped closer to 400 once I turned on the control switch. Still nothing. Based on all this, I'm assuming that the gas valve is (still) bad, even if the thermostat (or whatever is at the other end of the black wires) is bad, too.

Any further advice from anyone would be appreciated. We'd like to make a decision (repair or replace) by the end of the weekend.

Thanks again.

 

[griffths]

I know this is an old post and you have likely resolved your issue one way or the other but in the event you have not......

I am having the same trouble with a neighbors Lite2 heater. I have followed all of the troubleshooting steps in the manual and even went as far as removing the thermopile to see what voltages I could get when heating it on the gas kitchen stove. I was able to read over 1000mv so I called Jandy for assistance and was told that if the pilot light is lit and the main burners don't come on then the gas valve is the source of trouble and needs to be replaced. When the thermopile was in the circuit I was measuring closer to 470 with the on/off switch in the off position and about 450 with the switch in the on position.

Regards,

Jay

 

[ps0303]

450 should lite it up. You could get 500MV but if you have a problem elsewhere in the safety circuit lets say or the thermostat, it wont lite. So just because you get the MV's other things have to be good as well.

 

[griffths]

Everything else checks out OK. Bypassed all safety circuits and it still won't light. The Jandy manual says anything less than 500mv and it won't light but at 470 I would expect it to work anyway. I also checked the thermostat and temp sensor resistance values and based on the range listed in the manual, they don't appear to be the trouble. I hate replacing a part as expensive as the gas valve (http://www.poolsupplyworld.com/Zodiac-R ... 096400.htm?) without knowing for sure that is the problem so that is why I called Jandy.

 

[ps0303]

Honestly with the age of that heater you could replace the gas valve and maybe get the rest of the season to use it. Or you could replace the valve and still have issues. It's a Crud shoot.

 

[danpik]

I have to ask this as I just ran into this the other day. Is the gas valve turned to the on position and not set in the pilot position?

Is the pilot burning nice and clean, no noise (hissing), no flickering? Have you cleaned the thermopile?

The diagram I posted below is a general setup for how these circuits work. On the gas valve, terminal "D" is the TH/TP on your valve, "E" is the TP and "F" is the TH. If you jump the TH/TP to the TH it should lite.

 

[glutton4punishment]

Danpik, thanks for the reply. I've been meaning to post an update here. Yes, the valve was set to the correct position (but it doesn't hurt to ask!). I bypassed everything, I cleaned everything, I replaced the thermopile and the pressure switch. I had a good flame on the pilot, but even when I heated up the thermopile with a torch (to achieve more than enough millivolts), the gas valve would not open. I worked on this thing for a week (under an umbrella, in the rain... it was great fun!).

I wound up purchasing a new heater. I got the Raypak 266K BTU NG Electric (so I had to wire this one). So far, it works like a champ. Heats the pool twice as fast. And the digital thermostat is a huge luxury compared to the dial on the old millivolt which was just a guessing game.

I salvaged all the parts from the old heater (before leaving it out for the local scrappers) that were in working condition, either for myself or a friend who is currently troubleshooting his millivolt heater.

Thanks for all the help here!

 

[ps0303]

Danpik, thanks for the reply. I've been meaning to post an update here. Yes, the valve was set to the correct position (but it doesn't hurt to ask!). I bypassed everything, I cleaned everything, I replaced the thermopile and the pressure switch. I had a good flame on the pilot, but even when I heated up the thermopile with a torch (to achieve more than enough millivolts), the gas valve would not open. I worked on this thing for a week (under an umbrella, in the rain... it was great fun!).

I wound up purchasing a new heater. I got the Raypak 266K BTU NG Electric (so I had to wire this one). So far, it works like a champ. Heats the pool twice as fast. And the digital thermostat is a huge luxury compared to the dial on the old millivolt which was just a guessing game.

I salvaged all the parts from the old heater (before leaving it out for the local scrappers) that were in working condition, either for myself or a friend who is currently troubleshooting his millivolt heater.

Thanks for all the help here!

I think you made the best decision on a new heater. You always have to look at your investment vs return. Yeah you could have guessed and replaced the gas valve on the old unit but who's to say tomorrow another problems comes up.

You've learned a lot from working on the old unit but this new one will be a lot easier and get you more pool time with less frustration.

 

[glutton4punishment]

I think you made the best decision on a new heater. You always have to look at your investment vs return. Yeah you could have guessed and replaced the gas valve on the old unit but who's to say tomorrow another problems comes up.

You've learned a lot from working on the old unit but this new one will be a lot easier and get you more pool time with less frustration.[/quote]

I definitely feel like an "expert" on 30-year-old millivolt heaters now... is that an employable skill? Anyway, I forgot to mention that soon after firing up the new heater, the pump motor died! It was equally old and beat up. I went through the same diagnostic process but finally replaced it. Then the spa pump motor (for the jets) wouldn't go - I managed to clean that out enough that it runs, for now. Bascially all of this stuff was equally old and tired, so it's all giving up at once.