Glowworm Compact No Central Heating

Was asked by a lady to look at her Glowworm Compact as her central heating was not working. The hot water was working, but she did complain that it was a too hot if anything of late. The lady could not understand why the boiler was constantly running even though the central heating was turned off on the timer.

Looking at the boiler it was running even though the timer was turned off. Looking at the symbols on the boiler I could see that the tap symbol was illuminated even though there were no taps running and the boiler pump was running. I turned the timeclock on but nothing changed with the boiler. I opened the tap and the water was very hot, and cooled a bit before the boiler fired up.

After I turned off the tap, the boiler still continued to run for a while before getting too hot and cutting out. The tap symbol remained illuminated. I ran the tap on and off a couple of times and the tap symbol extinguished, then the heating symbol came on and the heating began to work. I tried the hot water once again, and after I turned the tap off the tap symbol stayed illuminated.

I removed the hot water microswitch on the right hand side from it's position over the pin which operates it. Once removed the hot water symbol extinguished and I could see that the pin was still out quite a way as if a tap was open. I was able to push the pin back in with my hand which I should not be able to do if a tap was actually open.

I replaced the diaphragm (Parts Center 440776) in case it had stretched and the diaphragm cover (Parts Center 440100) in case the pin was corroded and sticking. Another happy customer with working heating and hot water.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.