I have a MasterTemp 400 heating a spa only and control the heating of the spa with the MobileTouch (along with it controlling many other pool related functions). I just ran through a scenario again where the MasterTemp and the MobileTouch were both reading the spa temp as 48 and 49 degrees respectively after I turned on the spa only, no heat. I then turned on the MasterTemp with the MobileTouch. The MasterTemp fired up normally. Approximately 10 seconds after the heater fired up, the temp reading on the MobileTouch began increasing by 10-12 degrees, then pausing for a few seconds, increasing by another 10-12 degrees and continuing this scenario until the set spa temp of 100 was showing on the MobileTouch after which the heater would shut off. The MasterTemp still showed a temp of 48 degrees.
The MobileTouch spa temp would then start dropping by 10-12 degrees at a jump and pretty soon the heater fired up normally. Then the whole scenario
I've talked about so far would repeat itself. To note, the temp on the MasterTemp always showed 48 degrees. All indicators on the MasterTemp were normal. The scenario described above only took 2-3 minutes max to run through so I wouldn't expect the MasterTemp temp reading to change.
Any ideas on the problem?