Gas spa heater ignition lockout when raining
Hi! I’ve got a Pentair MiniMax 100 natural gas spa heater. It’s new to me, but approximately 12 years old. After a lot of cleaning, I’ve got it wired up and functional, but I’m running into a very strange issue. In normal weather it works ok, but when it’s raining out (that’s my theory anyway), the heater won’t stay lit. The electric ignitor sparks, the gas ignites, but then the ignitor isn’t sensing that the flame actually lit. At that point (I think it’s 4 seconds total), the heater shuts of the gas supply and the flame goes out. However, this problem seems to only occur when it’s wet or raining out. Any ideas? A lose wire somewhere? A bad ground?
Here’s the manual that includes a wiring diagram. This is the direct spark ignition model:
Here’s a video of what happens:
I tested the current at on the flame sensor, and it’s peaking at .3 microamps. So I’m pretty sure the flame sensor is the issue I need to track down here. I’m thinking it could be a ground-related issue since this seems to work ok in dry weather but not in wet weather.