Leave the jets off.

Turn the knob from low to high and that should turn on the main pump to low speed.

See if that works.

If not, then change the switch position on the front panel of the controller (that freeze thing).

if you mean the temp knob, should it automatically start circulating if I switch it to high? If I'm not in freeze mode or I haven't got the clock starting the circulation, the temperature dial only clicks quietly, the heat light on the command center comes on but nothing else happens.

Thanks again for your help - I'll leave it running on freeze mode overnite and let you know how it went

Was your previous topside control thermostat made with a copper tubing type of sensor (capillary)?

And, does the new one have something different (as in wire with plastic sensor case)?

Good Morning
Both the same other than four buttons instead of 2 on the newer command center (jets 1, jets 2, blower and light - just using jets 1 and light) The original one had just jets 1 and light otherwise looked exactly the same (both tecmark command centers). Both have a grey wire with what appears to be a 2" black plastic sensor on the end - This plugs into a white tube on the moulding of the tub.

I've just played with the pressure switch, loosening it and heard a click and a low hum - not automatically circulating the water though - should it do that? The heat light was off on the command center. I then started the circulation on the timer and the command center heat light came on (still no heat light in the main box)

Current temperature is 57 so i'll give it a couple of hours and check it again. We have snow here and current temp outside is -2. If working, roughly how long should it take in these conditions to heat?

Hopefully discovered the problem - when my friend had the spa guy out he replaced the relay. The only problem being that he replaced it with a 240v relay instead of a 120v.

New one on order so hoping for the best.

Thanks again for your help.