by UFH1
1. If you have a fault once the system is up and running, the first thing to check is the flow rate in the flow meters. Make sure they are set between 1.5L/min and 2L/min for boiler use and 1L/min for heat pump use. If there is no reading (the red indicator is at the top) nothing is flowing around the loop.2. Then take off your actuator heads, if you then get a flow or your system then works you know it is an electrical problem. If after taking all the actuators off you still have problems then it will be a flow fault