Many thanks. I will put a jumper across the flow switch connectors to see if it is the flow switch that's open. When you say thermistors, do you mean the Control Sensor and High Limit Sensor as I replaced both of these as the High Limit Sensor was defective?
Can anybody tell me what the constant red LED on my control board means? The LED is located next to the marking D21 and below marking F51. The other LED's that are lit are Limit OK which is constant green and PWR ON which is flashing green. On the outside of the tub the Hotsprings Logo lights are both flashing too.
I have checked the and fitted the following;
1. New filter.
2. New High Limit Sensor.
3. Checked circ pump for air lock - all clear.
4. Tried new circ pump but to no avail.
I want to confirm these LED's before I start investigating possible blockage.
Cheers