This 10 year old boiler sometimes won't start Central heating, only when a hot water tap is opened and then closed, will get the boiler working for CH. Then it can be switched on and off with the room thermostat and will work just fine, but when its off for a few hours, could need (not always) the "little help" of the hot water tap to get it going. What could it be? the diverter valve? the microswitches? Thanks in advance
If the DHW works OK then the problem is most likely the diverter valve. Especially if the boiler fires up for a few seconds then stops when you but the CH on.
Generally the diverter valve is driven into the DHW position but returns under spring pressure to the 'normal' CH position.
Ed Sirett ha escrito:
Thanks a lot Ed for your response. Gave me the push to look into the boiler and I fixed it!
For what is worth, the fault was in the CH microswitch. I opened the case housing the switches, and checked how the plunger would come out when the DHW tap was opened, switching off the lower switch (CH) and then switching on the upper one (DHW), pretty cool to watch!! When closing the tap, it would come all the way back, so thankfully it wasn't the diverter valve ventury failing. Then I swapped the switches and sure enough, DHW wouldn't switch on anymore, but CH was then fine. I then checked the original CH switch with a tester and it showed that it would sometimes switch and sometimes it wouldn't. Since today its Sunday and I'm not even sure if I would find spares for it, I soaking sprayed the switch with Kontakt (fairly useful product used in electronics to clean all kinds of contacts and potentiometers), sure enough did the trick at least for the time being until I get a replacing switch.
Thanks again /F.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.