Hi,
I'm hoping someone on the forum has some technical advice for me because this is going to drive me nuts! I don't want to have to buy a complete new board for 450 bucks if I can just replace a component. I am fairly handy with electronic and electrical stuff.

I have a 2001 Charisma hot tub, fitted with a Hydro-Quip control pack. (Board is 33-0010-R5). This pack can accept 120V or 240V input. I have it wired for 240V.

The pumps and blower are functioning fine.
The external LCD control panel is fine
The water is not heating.
If I dial up/down the temp setting on the LCD control panel I see the "heating" icon appear and I can hear a solenoid clicking on the board.
The temperature probe seems to be working OK.
Connecting/disconnecting the flow/pressure switch from the board causes a solenoid to click, which I interpret as meaning this is working OK.

I have checked all the fuses on the circuit board - all are OK
I have used a multimeter to test the heater coil:
- I get 10 ohms across the two heater terminals (which I think is OK for a 5.5KW heater)
- on each of these two terminals I get 120V to ground.
- I get no voltage across the two terminals.

Any advice on next steps or likely causes will be very gratefully received!

Many thanks!
Cris