Okay, it's a cheap inflatable spa but it's all I can afford and I have RA. From all I've read on this and other forums, I believe my temp sensor is shot (water flow fine, new filter, bled the pipes for air bubbles)..the "OH" comes on and the display blinks rapidly from 100-104. Heat water up to about 98. Ran without filter, same thing. Problem is, Comfort Line won't sell replacement parts. They only want people to ship the whole power pack to them and they send a rebuilt one for like $450.00. I'm on my second power pack and out of money. Common sense tells me there has to be a comparable replacement sensor somewhere, even if I have to solder the sensor part to the plug and waterproof the wire. Can you help me please?