The amber light on the receiver should be lit when heating request has been received from the thermostat/controller. If it is, but the boiler does not get the demand then either there is a wiring error or the relay in the receiver is faulty. This is the problem I have. I took the front cover off the receiver and tapped the area of the relay (just to the left of the L1/Lx/L2 terminals) a few times with an insulated object and the boiler got the signal and came on. I'm buying a new unit!
Dave H, June 2012
