Teldyne Laars Series 2 ESC wont fire

[mgill]

Hi everyone,

I realize this heater, as some would say, belongs in a museum. But Id like to get a few more years out of it if I can.

The heater is a Teledyne Laars Series 2 ESC 400k BTU heater running on natural gas. About six months ago the temp dials and the on/off switch were getting flaky - the heater finally stopped working last week. When I opened it up it was clear the wiring needed some TLC. Ive just completed replacing the ignition control unit and the temperature panel along with some other wires that were fairly well melted. After I replaced all the electrical parts (which was almost everything) I tried to fire it up - but no go. All the electrical troubleshooting steps check out, and I can trace all the way to arcing coming off the spark line for the pilot. Turning the furnace switch on brings the sound of the furnace clicking to light itself - everything electrical appears to be good.

So I think I'm down to two parts left that are keeping the heater from firing - the pilot light assembly or the main gas switch. Picture below is of the main gas switch with the main gas line coming in from the left. I was going to pull the pilot line that goes down into the right side of the gas switch but unscrewing the nut brings the line with it, and its going to break (you can already see a twist in the line from my attempts to unscrew the nut). I cant get the pilot line off the switch. Based on other posts I thought if I could get that line off I could tell if Im getting gas there - and that would tell me if the pilot assembly is bad or if the gas switch is bad. But Im stuck.

So lets assume I replace both parts. Here are my questions:

1. How in the world do I get that main gas line unscrewed from the gas switch? If I unscrew the pipe so it unthreads from the switch the pipe is tightening at the other end where it goes to the main line on the outside of the furnace. That pipe isnt going to do that - how do I get the main gas line out of the switch correctly?
2. Any ideas on how to get the pilot line off the switch? That nut should screw off without the line twisting, yes? should I snap the line just above the nut and then re-attach with a slightly shorter line?
3. Other ideas Im missing? Any other ways to troubleshoot?

Thanks everyone - the forums are always so helpful! Pic below:

 

[ps0303]

If you can't get the pilot line out of the gas valve, well, that's not good. Yes you could use a small pipe cutter and cut it and then once you replace the pilot you can use a brass coupler to couple the old line to the new.

 

[mgill]

Thanks for the note Paul. As I continue to research what to do next I'm discovering that my installation is missing a crucial thing - the connector in the incoming gas line. Every other example I see on youtube and other places the pipe can be disconnected inside the furnace area to enable manipulation of the gas valve and subsquent parts. Super frustrating to see that my installation does not have this.

Here is an example: Jandy Laars Lite2: Hot Surface Igniter Replacement. - YouTube - not the exact same heater but pretty close. Go to the 2:10 mark to see what I'm missing

Now I'm thinking of just having a plumber come to remove that main line and reinstall it with a similar connector. Once I have that I'll just replace the gas valve. My new connection will also allow me to pull out the bottom tray to replace the pilot assembly as well.

 

[ps0303]

It all depended on who did the install. It's really not code to have the union inside the heater like you see on the video. Yes it's done but you're really not supposed to do it that way.

Hopefully when/if you remove the burner tray it's not so rusted that it falls a part. Id that happens, I'd say time for a new heater.

BTW, not to nick pick, but is a pool heater, not a furnace. A furnace is installed inside to heat a house.

 

[mgill]

You can tell this isnt my day job. Pool heater it is.

Yes, the bottom tray had some rust but looked like it had a few years left. - from what I could tell the structure of the tray was still intact. We will see what it looks like when it comes out.

Regarding the union - without a union in that line how do you ever replace the gas valve? A union outside the heater? Obviously being a plumber isnt my profession but it seems crazy that you have to completely re-plumb the incoming line every time you have to service the gas valve.

As I missing something in how to replace the gas valve?

 

[ps0303]

Well I CAREFULLY cut the pipe inside and remove the two pieces. Then after any work is done on replacing the valve, I replace the pipe with two short pieces and a union. I know I know I just said earlier you shouldn't put a union inside. But like my parents always used to say "Do as I say and not as I do." LOL

 

[OldPoolMan]

Actually here in California, putting the union inside the heater jacket is the preferred method of installation. Can't see your pictures but the gas line should be redone from the closest outside fitting. Be careful when working with gas!

 

[mgill]

Thanks guys. So it appears Im at a decision point - do I stop what Im doing and call the plumber to redo this gas line or do I just have a new heater installed. Its a tough call. Based on what I can see underneath there is alot of rust down there - but I cant really tell if the bottom tray is toast or not. If I have to replace the bottom tray with all the parts Im into this about $1500 - that means to me might as well be getting a new one.