Pentair Mastertemp 300 turns on spa when it's not supposed to

[Vinisterz]

I have a Mastertemp300 heater that turns on by itself when it's not supposed to.

It is gas fueled and hooked up to a intermatic timer with the pool pump. But it is not supposed to turn when the pump is on.

I have tried to turn the heater completely off, turn the pool pump timer off. Restarted the timer and both the pool pump and heater with the spa light turns on when only the pool pump is supposed to turn on.

What could be making the heater turn on as well? Any ideas? Thanks in advance for any advice given.

 

[ajw22]

So you control the heater through the keypad on the heater?

Does the Heater OFF button turn the heater off? Do the SPA ON and POOL ON buttons work?

I suspect you have a bad membrane keypad. It is

Amazon.com : Pentair 472610Z Switch Membrane Pad Replacement MasterTemp Pool and Spa Heater Electrical System : Outdoor Spas : Garden & Outdoor

Amazon.com : Pentair 472610Z Switch Membrane Pad Replacement MasterTemp Pool and Spa Heater Electrical System : Outdoor Spas : Garden & Outdoor

www.amazon.com

 

[Vinisterz]

So you control the heater through the keypad on the heater?

Does the Heater OFF button turn the heater off? Do the SPA ON and POOL ON buttons work?

I suspect you have a bad membrane keypad. It is

Amazon.com : Pentair 472610Z Switch Membrane Pad Replacement MasterTemp Pool and Spa Heater Electrical System : Outdoor Spas : Garden & Outdoor

Amazon.com : Pentair 472610Z Switch Membrane Pad Replacement MasterTemp Pool and Spa Heater Electrical System : Outdoor Spas : Garden & Outdoor

www.amazon.com

Yes the off button works and the temp up down buttons, and the pool button works. But the spa button does not work. When it turns on automatically, it starts the spa heating. I was able to switch it to pool, adjist the temp, and turn it off with the off button. Should I try to replace the keypad membrane?

 

[Vinisterz]

So you control the heater through the keypad on the heater?

Does the Heater OFF button turn the heater off? Do the SPA ON and POOL ON buttons work?

I suspect you have a bad membrane keypad. It is

Amazon.com : Pentair 472610Z Switch Membrane Pad Replacement MasterTemp Pool and Spa Heater Electrical System : Outdoor Spas : Garden & Outdoor

Amazon.com : Pentair 472610Z Switch Membrane Pad Replacement MasterTemp Pool and Spa Heater Electrical System : Outdoor Spas : Garden & Outdoor

www.amazon.com

Thanks for replying and suggesting the keypad membrane! I looked at the reviews and found a few that has the exact problem I'm having. I bought mine and going to replace to see if it fixes it.