chazz

Thanks for the reply's Well I think I have it sorted out. Checked all systems and found no water entering tub (in foot well ) at outlet for circulating pump. Voltage test on heater lugs shows circuit open (no voltage) at start up of therapy pump which also feeds heater and then circulating pump. After 2-3 min relay closes and voltage at heater shows 220v a short time later (1 min or so) relay drops out voltage drops to zero and tub shuts down. DIAGNOSIS: Bad circulating pump. From what I know the two sensors on the heater tube detect temp and flow. Difference of temp or pressure between the two shuts tub down. In my case there is insufficient flow or out of spec temp difference between the two causing fault. Comments?

While out of town my wife said tub shut down and showed Pr on control panel. I bled both pumps (two plugs on each pump) reset and powered up. Good flow from both pumps but after 5-7 min the system shuts down and panel says Pr again. I bled a couple of times with same result. Is this indication of a sensor failure? Where is the sensor (I assume it is a flow sensor) for this system located? As far as I can tell (I am new owner to this spa) water enters heater from foot well and then is circulated back to tub. Is the small black device (see attached photo 4" in diameter and about same length) on outlet side of heater tube a smaller circulating pump for the heated water? As far as I can see the therapy pump water flow is isolated from the heater water flow system.