Pool heater shuts off after 1 minute

[rsaritzky]

Hi,

My mom has a 30-year old Teledyne Laars pool heater. The heater will fire up, then shut off after about a minute or two. If I move the thermostat up, it will fire up again, then off in a minute or two.

Her pool serviceman says that the heater has to be replaced - I don't have much confidence in his knowledge of heaters and heater repair.

I've read on this forum some info on limit switches and pressure switches. I'm a relatively-savvy home DIY'er, but have never owned a pool. The heater gets lots of pine needles and spider webs. There's plenty of water/pressure coming out of the ports in the pool (I also read on this forum that sometimes low pressure can cause a heater to shut off) Other than cleaning out the obviously accessible areas (e.g. burner tubes, chimney), does this sound like a problem that a good pool heater repair company might be able to fix?

Thanks for any advice

Ron

 

[PoolGuyNJ]

That sounds like one of the hi-limit sensors but if the heater is that old, finding new ones will be ridiculously hard, at best. Generally speaking, 30 year old pool heaters would have had been obsoleted and no longer supported over 10 years ago. It's also possible that there is a reason other than old age for the tripping of the hi-limit.

This heater has more than met it's expected lifespan and she has more than gotten her bang for the bucks it originally cost. More things will go wrong in short order even if she's able to find the hi-limits for this heater. I don't think it makes sense to continue to throw money at this heater.

Scott

 

[Bama Rambler]

To slightly with Scott. If it's just a high temp cutout it would well be worth changing it out. But from your description it sounds like the t-stat is taking it out. At what point does moving the t-stat up not bring the heater back on?

Can you take a pic of the t-stat and post it?

 

[Poolsean]

If you are competent with mechanical skills, Hi limit switches and pressure switches can be tested for continuity to see if they are working. They can also be jumped out to test as well.
However, you are dealing with a gas heater, so care and caution must be observed.

 

[rsaritzky]

Thanks for the advice. I'm a bit familiar with furnaces, and I found a part inside the heater that mentions something about being a pressure-limit switch. Is there any place with some illustrations of what I should be looking for?

I'll post a picture of the thermostat too in the next couple of days. It appears to me to be an external addon t-stat (it was already there when my folks bought the house in 1994.) The reason I think it's an "addon" is that there is another thermostat knob built into the heater cabinet, and this on looks like a box that is bolted onto the side of the heater.

Good point about replacement parts, although if it were a home furnace, you could get basic parts for even 30-year-old ones.

Thanks again for the words of advice - more later.

Ron

 

[PoolGuyNJ]

A possibly cracked wire, when heated, separates, breaking the safety circuit's continuity, is another potential area worth looking for.

If this heater is 30 years old, it's time. Comparing it to a home furnace is like comparing it to a car. They are different beasts. Ever seen a 30 year old hot water heater?

Scott

 

[mickey4paws]

We replaced a 20 year old gas heater last year. It would do the same thing, start fine and then shut off. The burner tray was so rusted and other problems that we decided it wasn't worth putting any money into it. We love the new heater plus it's way more efficient, i.e. lower gas bills.