I just bought an old ECM Giotto and some how it won't refill the boiler. The pump kicks in as it should but the water just passes through to the return hose and back into the water tank again. I suspect the solenoid valve could be the fault, but some water do pass through this, just very little and not with enough pressure to reach the boiler. I have seen some diagrams of a ECM Giotto which show a expansion valve, mine does not have that. I have included a picture. I hope someone out there can help me out with this one.







