A Halstead Wickes Combi 102 (Ace High) installed in a let property fails to modulate to full heat under demand for central heating, so the radiators are not getting hot. The pressure remains stable at 1,5 bar. When hot water is called for, the boiler responds to full heat. After a while the pump overrun stat takes over before the boiler fires up again.
Any advice on what is causing this and remedy? Pcb? A blockage in the CH system?
The problem emerged soon after I cleaned the DHW heat exchanger to resolve the hot water problem and the system was drained and flushed with Fernox restorer. All radiators are bled and the Grundfos pump (recently replaced) seems to be working fine, but has to be kept at maximum speed to keep the radiators warm.
Would call in a corgi if its a gas problem but need to be sure that the problem is not a system blockage. The boiler was installed 4 years ago.
Any advice on what is causing this and remedy? Pcb? A blockage in the CH system?
The problem emerged soon after I cleaned the DHW heat exchanger to resolve the hot water problem and the system was drained and flushed with Fernox restorer. All radiators are bled and the Grundfos pump (recently replaced) seems to be working fine, but has to be kept at maximum speed to keep the radiators warm.
Would call in a corgi if its a gas problem but need to be sure that the problem is not a system blockage. The boiler was installed 4 years ago.
