kentp

Hi all, first post here so please forgive me if I do something wrong... I have a 12 year old Southwest Spa with HydroQuip guts (product HQ6000 - order code CS6220-U). A few weeks ago I drained the tub and cleaned it like I do regularly, and after filling it took twice as long to heat back up. Normally it takes roughly 4 hours to heat and this time it took 8. On top of that it has been having a hard time keeping the temperature at 100. Where before the pumps/heater only came on as needed, now they are running all the time. Last night I noticed that the temp has begun to fall as it was at 96 and holding. the top side controls say that the heater is on (or calling for it), but I don't see the heater light on the controller lit. All other functions and flow seem normal, and there are not any error codes or warning lights. I will put an ohm meter / multimeter to it this weekend, but my initial thoughts are that the heater may need replacing. Thoughts? Suggestions? Any help is greatly appreciated. thanks, Kent