Teledyne Laars Heater starts but won't stay on

[Rickoxo]

I have a Teledyne Laars Lite Heater (model LLD) that I got from uninstalling a cedar hot tub on a construction job I did. I hooked the heater/filter/pump up to a 150 gallon rubber maid tub I use as my homemade jacuzzi and everything had been working fine for the first ten uses

Now when I turn it on, the water pump works fine, water flows through the system but when the heater is getting ready to turn on, it sounds kind of like a geiger counter, a series of light clicks, irregular pattern, keeping going over a minute. If I turn down the temperature, the clicking stops, but if I keep it at max (where I like it for jacuzzi), it keeps clicking.

The bigger problem, however, is when it lights. It still does light, the electronic ignition kicks in, the gas flows, the heater lites, but then it starts clicking loudly, a few, pretty rapid clicks which the last couple of times have resulted in the heater shutting off. It goes through whatever timer cycle it does before it checks temperature again, then repeats the light clicks, the lighting, the louder clicks and the shutting off. First week or so of use, no problem getting my tub to 104 degrees in about 30 minutes, now it heats the water slightly from the brief turn ons, but won't stay on long enough to heat the water over 75 degrees.

First, anyone know what is wrong and what part(s) I could replace to make the world good again?

Second, I wouldn't mind bypassing the temperature control on the panel and controlling the temperature manually. I get that's more effort and I'd need to be careful, but Ihave roughly 100 gallons of water in my tub and it heats up in almost no time. I don't use it on any timer mode and I don't leave it running. I heat it, use it, and turn it off. So is there an easy way to bypass whatever things are clicking and being a pain and simply tell it to ignite and stay on till the water is hot?

The only part of that I wondered about is, does the heater need to cycle on and off to not get too hot? I have a 1/2 hp pump with 1 1/2" lines pumping water through, so would letting the heater stay on till the water is hot enough work or would I need to turn it on for a few minutes, turn it off, turn it on, turn it off until it's at the right temperature?

Any thoughts/suggestions appreciated, sorry the picture isn't so good, but just in case that helps clarify what I actually have and what's going on ...


Rick

 

[Rickoxo]

A bit more info, here's a picture of the actual wiring and the schematics page if this helps at all. I made a sound recording of the heater doing the geiger counter sound (I also thought it sounded like when you turn the dial on the washing machine to get it to the right setting, that kind of clicking, but quieter). Unfortunately the forum said it didn't allow .mp3 files. If there's another format, let me know and I'll try again to post it - Rick

 

[Rickoxo]

If no one has any clues about fixing this, does anyone know how to bypass the water temperature sensor to make it so that I can turn on the heater by turning on the switch? I'm not a wiring guy in terms of figuring it out from the diagram, but I could connect a jumper or move wires if I someone told me what to do. I would really love to get this back working ...

 

[frustratedpoolmom]

I wish you had received a response - I have a similar model and I've never heard mine do what you described.

Unfortunately areas around the country are hitting their peak "open" season and many of our mechanical experts are out busy working on pool openings, etc and aren't around as often to post responses. Hopefully someone will see this and get you some answers...

 

[MikeMan]

Rick- Your LLD heater is an electronic ignition heater. Rather than having a standing pilot you have a hot surface ignitor. When you turn your center dial to pool or spa you send a signal to that heater to start checking all the safety. (pressure switch, flame roll out, high limits, timer switch) after your heat identifies that all those circuits are closed than it starts the firing process. The firing process takes about a minute. After you turn it on First you should hear a click. (its gonna take a few seconds) Second with the front door off you should see a red/orange glow down by the burners (very bottom) Third you should get ignition. Than the unit needs to recognize that the heater has been lit and shut the hot surface ignitor off. The way in which the heater identifies that ignition has happen is by a flame sensor. Which plugs into your Honeywell Fenwall board in the top right of your heater (where all the wires go) When the heater lights and turns on you should no longer hear clicking. If you do that heater has no idea that it had fired and continues to keep trying to fire. After three tries your heater stops and shuts down until you turn the switch and try it again. The way you describe your problem points directly to the flame sensor. The flame sensor normally has one white wire coming out of it if im not mistaken. It is going to be located under the gas valve going into the burn chamber. Im pretty sure with a 1/4 nut driver you can pull that thing right out. With a new flame sensor id say all your problems are gone. And to answer you second question, there is no SAFE way to jump a thermostat.

 

[Rickoxo]

Mike -- thanks a ton for your time and for the info. That makes total sense except for one thing -- I went looking around a number of parts stores and looking all through the schematics, and there's no mention of a flame sensor and no parts store sells a flame sensor, at least not by that name. I saw a flame sensor rectification kit, but it was for a different model heater. Here's the link I was working from for this heater http://www.csiworldwide.com/Parts/Laars Parts/Laars Lite LLD Parts.htm

Any chance the flame sensor is built into the igniter? That seems to be the only electrical piece located down in that area. There is one piece called a temperature sensor, but it isn't listed for the LLD either.

So I tried it again tonight and now it seems to be getting worse. It was doing the geiger counter clicking again, I could see the igniter light, but now it won't even turn on the gas, and the igniter seems to be starting and stopping, not just trying to light the gas three times, but it gets hot, then cools down a second later then gets hot again then gets less hot, then back up, all the while the clicking is going on. It cycles off then tries again and it did the same thing, not just turn on, get hot, wait a few seconds, turn off, but turn on, get almost hot, cool off some, hotter, clicking, etc. It was more than hot enough for the gas to light, and a couple of times it had stayed lit for a while (in case there's some sensor that says its hot enough to turn on the gas), but the gas wouldn't come on any of the times I tried.

Does this make any more sense, does it still sound like a flame sensor and any thoughts on where the flame sensor is? Thanks, Rick

 

[krockswell]

Hi Rickoxo

We have a nearly identical problem with the heater not staying on, and the thermostat (?) making a clicking racket. I checked the voltage along the line of components and got 24 V, as per specs. The exception is the thermostat (I think it is the thermostat - a black box attached behind the circuit board). The voltage for the thermostat wire that comes out of this component fluctuates wildly, and the clicking noise is coincident with the voltage fluctuations. Does this still sound like the flame sensor? IF so, did you ever find another term for it? Did you find a way to resolve the problem or part that needed replacing?
Thanks, Kim and Tom

Thanks,

 

[jjrepko]

I have same Laars LLD heater. Until today it worked fine since I last replaced some parts 2 yrs ago. But today it does not ignite. The igniter glows - three cycles. And there's the usual click sound while the glow is at its peak. But no ignition and no gas odor. The 500 gal. propane tank is nearly full and the valves are both in on position, of course. I always thought that click was the gas valve turning on, but no gas flows. Could it be the flame sensor - assuming that sensor also senses when the igniter is up to proper temperature?