Fuse blowing on Altech/JG Speedfit underfloor heating system

[Nikita]

Hello,

I have a wireless underfloor system controlled by altech receivers and transmitters. There is also a JG speedfit control board and distribution board. As soon as the transmitter connects to the receiver, a green light turns on and the actuator valves on a manifold attempt to turn on. As soon as this happens the fuse on the control/distribution board blows. At first this took a while but after replacing the fuse 2 times it had become instant as soon as the receiver connects.

What would be your suggestions to what could be wrong?

Thank you

 

[Vee]

If you have the pump with the suppressor fitted on the pump supply wire (chunky black section) in particular it could be a pump problem. Only option is to change the pump in that case. Check for dead short (continuity) on pump wiring. Or disconnect the pump from the controls and try another fuse...