There is no pilot light. It has a hot surface ignitor.

From the photo I see there is/was an excessive amount of heat inside. Perhaps a flame roll out burning the inside of the door.

The heater should have a good going over before firing. There may be soot on the exchanger which in turn generates much more heat in the cabinet. But this is just a symptom.

There may be excessive water or low gas pressure or both.

Many times rodents make nests on top of the exchanger and create problems.

The burner tray should come out and should be cleaned as well as the inside of the cabinet.

I just replaced this model with a Jandy JXi. The original heater was installed when we built the pool 14 years ago.

Contact Jandy and find a dealer in your area. Shouldn't matter it's an above ground pool. Like you said, it's just a heater. We build inground pools but have serviced Jandy products on above ground pools.

VERY much appreciate the detailed reply. I am going to give it a deeper inspection. I am also attempting again to find a local pro to come out. I live In WI so pool servicing isn’t the most popular business.

I did contact Jandy last year and their referral was the company who wouldn’t service above ground Pools. I even questioned why it mattered for heater service. I assume they figured if they can’t sell me on additional services then it wasn’t worth their time.

Most heating and AC companies should be able to help if you cant find a pool company that will service it.

Yes we actually got in contact with an electrician and a pool company yesterday, both said they could help but suggested we connect it and simply see if it leaks first. If it leaks I’m told it’s not worth repairing.

Does anyone know if I should try to flush it out before connecting? Like run hose water through it? or Just hook it up, fill the pool and see what happens?!

Just hook it up and look for leaks. If there are none, then it's worth trying the heating function.. However, if it hasn'r been used for over 5 years, it will most likely need some work before it comes on.

The burner tray should be removed and cleared of spider webs in both the burners and the gas orifices.

To remove the gas orifices on the burner tray pipe, you'll need a 7/16" box wrench. More than likely there are spider webs inside which impede the gas flow which can create a VERY ABRUPT ignition. It's very important they are cleaned out! I've had the front doors blow off.

I would remove the grate top and look inside on the exchanger and make sure it's cleared of any debris or rodent nests. A shop vac will work well. You'll need a 5/16" nut driver to remove the screws that secure the top. Just pay attention as to how its set before removing so you can put it back correctly. They can be a little tricky with the sheet metal moving around.

After you're certain you have cleaned it, run the pump and check for leaks and then turn on the heater. Stand off to the side at this point and see if it lights off. Those models make 3 attempts to light and then shut down. You would have to turn off and then turn back on again to reboot it.

Honestly, its very likely to leak. A general lifespan for a pool heater is about 10 years, with leaking in the heating piping being the most common failure mode. If you elect to try Mystic Pools suggestion, please follow it carefully and completely...a leak in the gas piping is much less likely but very dangerous, and as he notes, even a few burps in the gas feed can cause localized fireballs.

Thanks everyone. I am super appreciative of all the detailed replies.

I am super nervous to try this out but I can’t justify buying a new one without trying this one first. I can’t have a pro come out without first hooking it up and filling the pool so seems I have to just go for it.

I am not sure whether it sitting for so long helps or hurts us as far as age.. it’s older but we don’t know how many years it was actually used. Previous owners of 30+yrs passed away and their children initially wanted to keep the house so they certainly would have had incentive to maintain this stuff. The heater was covered and all equipment disconnected and stored which leads me to believe they did their best to maintain. We have just been too lazy to figure this out until now. We shall see....

Just remember to get water through the heater first to look for leaks and make sure to have water circulating when you try to light it.

Forgot to mention a pipe cleaner works well to clean the gas orifices of any cob webs.

More than likely you'll see some rusty residue come from the pool returns as the cast iron header in the heater will have some scale from sitting.