Teledyne Laars (Laars Lite) Model LLD - Stays lit for 5 minutes and then cycles off

[ploizzo]

Hello,

Need some help here with the pool heater. The heater (Teledyne Laars LLD) runs for exactly 5 minutes and then shuts off, goes through the lighting cycle again and fires up. Can't tell for sure which component is shutting it down.

Not a huge problem as it turns back on after a minute but i do like to have things working the way they are supposed to.

Any thoughts??

Thanks!

 

[danpik]

A model number of the heater will be a big help here. Also, was any work done to the unit or the associated equipment recently. At this point I am going to assume it is possibly overheating and all of the safeties are doing what they are supposed to do.

 

[ploizzo]

Model LLD400P

At the beginning of the season i replaced the transformer & the flame rod. Just turning it back on now that it is getting a little cold. It worked fine for about 3 weeks after i replaced those parts and then i turned it off for when it got warmer out.

Also, the pressure switch has never been replaced and it is does drip a little (not anywhere near the electrical connections or gas valve).

Thanks for your help!!

 

[ps0303]

Check your temp sensors on the header where the water flows in and out. Sound slike one of them is tripping the unit off and then the water cools it down and it starts back up. Also possible bad bypass in the unit, maybe.

 

[ploizzo]

How do i check them? i can't see where they are.

 

[ps0303]

Right under the return port on the header is a small metal cover with a screw on it. They are under there. You can simply rem0ve one and place a jumper wire where it used to plug in. Do one at a time.

 

[ploizzo]

ok, sorry it took so long to post back. I was able to check them yesterday...

2 things:

First there are 2 components that i am looking at and not sure which is the temp sensor you are referring too. There are the 2 high limit switches (which are below the return and in the metal box) and then there is the water temperature switch (which is in the header in the supply side). I pulled the high limit switches out and ran the unit with them hanging outside the exterior and it ran fine for over an hour. Then, I tried the water temperature switch once i put the high limits back together.... I cannot get the water temperature switch out of the header to test it. However, there are 2 black wires that go from the water temperature switch to the temp control panel (this is the front panel with the pool/off/spa switch and dials). I tried unplugging each wire one at a time and jumping each one individually and then across both but none of those configurations would allow the unit to start at all (which surprises me about what really happens in the water temperature switch??).

Also to note, the temperature dial on the front is set to max. Whenever the unit is running and i move that dial even the slightest bit it shuts off. I'm not sure what the water temp is going in and not sure what the max temp of this thermostat is rated at.

Any ideas??

Thanks again!!