I think I solved my own problem. I manually went through the ignition sequence cycle several times and the heater finally came on and stayed on.

The question is - what effects, if any, does heavy rain have on any of the components which are involved in the ignition sequence of the heater?

If you have an older analog controller, the rain sheild on this heater is very poor. Corrosion down the board is quite common. It is good practice to reseal this shield on a regular basis to prevent the board from shorting. As far as the combustion blower goes too, it is pure galvanized. It is good to turn on the heater after a period of rain as the lack of drying will further corrosion in the fan assembly. As far as ignition goes, a wet ignitor can be a cause of failure that you describe or air in the gas line.

To "repair guy" - thank you very much for your reply. I'm assuming the controller is the box that is mounted on the small swing-out door on the front right-hand side of the heater, and it has the digital readout and buttons for temperature control to the spa and pool. I also assumed that since the readout is a digital LED then the controller is also digital in its operation. The rain shield must be the opaque plastic flap that is attached to the back of it, covering the circuit board itself, which can be flipped up for inspection of the board. I'll check that as well as the combustion blower and ignitor.

Thanks!

Mine is not the TSI (from what I can tell) No led read-out. based on other stuff I have read, sounds like the Minmax was a poor choice.

Ours would not ignite...so the tech installed a new ignitor. Now it fires up, runs for a few seconds, the flame goes out, it ignites, runs, goes out, etc. It will do this indefinitely. From the led lights that are on or off, the manual says it is a thermal fuse circuit...but of course, I can't find the circuit in the manual...I did find what appears to be a fuse. it is covered in black rubber...is this what I need to replace.

any help would be great. I'll change tech's if it is something beyond me...I don't think he really knew what the issue is.

Typically a when a thermal fuse goes out it goes out.

Is the heat shrink tube melted and tight on the t.fuse??? If it is, it got hot, and I would have a technician investigate why it did get hot... Otherwise, replace it by unplugging the connectors on the end of the tfuse, and plugging it back in. Do turn off the power, not just for your safety, but so you don't short the transformer out if one of the connectors accidentally touches the grounded cabinet.

That's what I pretty much thought...it is not melted. the manual shows a series of lights that includes a thermal fuse circuit board...but i don not see that part listed anywhere...do you know where it is located? I'm not sure where to go from here...the tech that was out started talking about the ignition control module or a relay on the temperature controller module...but I think he was done to guessing...unfortunately it's very expensive guessing.

All of these items should be easily identified in the field by a qualified technician. I would get on them (service company) a little bit about not being able to pinpoint the defective part because this should be easily done.