I have a Honeywell system, Y plan, and can only get the radiators to heat up by turning up the room stat when the boiler is heating the water. Radiators will then heat while boiler is on, then switch off when water is hot enough. The boiler won't come on for the radiators on their own. After reading other postings on this site, I've tried replacing the synchron motor, but this hasnt' made any difference. Any other suggestions please?
radiators heat up only when water heating
- Thread starter ann46
- Start date
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OK - you've replaced the motor. But is the valve actually moving far enough to operate the microswitches to fire the boiler?
If it's a RELATIVELY RECENT Honeywell 3-port valve you can get a new actuator and fix it onto the existing valve body. Easier than draining the system to change the whole valve.
But if the valve is apparently operating correctly, I'd look elsewhere first. This could be a wiring problem. For example, there's a 'hot water off' connection which needs to be live to run the CH without the HW.
But if the valve is apparently operating correctly, I'd look elsewhere first. This could be a wiring problem. For example, there's a 'hot water off' connection which needs to be live to run the CH without the HW.
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Going back to your first reply, I'm not so sure that the valve really is moving far enough to activate the switches - it's hard to see this properly. When switched manually the microswitch for the heating does activate the boiler so maybe this indicates the valve isn't moving far enough? If it isn't, how can I rectify this? Wires seem to be okay.
I forgot to mention, the system is 15 years old. Am I going to be able to find a part for it? Had a real problem buying the synchron motor. Wickes staff wouldn't even admit they'd got such a thing - they swore they don't even sell them on their own. Had to show it them in the display cabinet before the staff would sell me one.
Also, looking at one of your other replies Croydoncorgi, will this invalidate my house insurance if it's a diy job? I'm getting help here by someone conscious of being careful with electrics, but we're wary of doing anything risky! We'll call someone in if we need to but if it's a minor thing maybe we can sort it.
Also, looking at one of your other replies Croydoncorgi, will this invalidate my house insurance if it's a diy job? I'm getting help here by someone conscious of being careful with electrics, but we're wary of doing anything risky! We'll call someone in if we need to but if it's a minor thing maybe we can sort it.
IF the head has a pimple on top you can change the head alone, though it costs almost as much as a whole valve. Changing the synchron motor is routinely done diy - hence the appearance in Wickes. I doubt it would affect your house insurance, it not like you're working on a gas appliance. There's a couple of standard microswitches in a head, which I've never tried changing, though I daresay its possible. Fairly floppy bits of bent metal make it all work , too!
Help! Things are getting more complicated here!
Basically, here's a rundown of what's been happening:
1. It's a Honeywell system Y Plan, fifteen years old.
2. Developed a problem where heating wouldn't come on. Could only get it to switch on when boiler was on to heat water - then it switches off when water is hot.
3.Tried fitting a new synchron motor. No difference!
4. Tested microswitch and found the switch for the heating is working, but valve somehow isnt' switching it on.
5. Put in a tiewrap as a wedge to put pressure on CH microswitch when valve moves, and heating now comes on. Nice warm house!
6. Big problem! Water also heats up when heating is on - even when the water is turned off at the timer. Also, even though the tank stat is only set at 60, it's getting very very hot!
We've checked for loose wobbly bits in the motorised valve - screws for microswitch were loose and now tightened. Otherwise, what would cause the valve to not move around enough? And why would water and CH get mixed up?
Basically, here's a rundown of what's been happening:
1. It's a Honeywell system Y Plan, fifteen years old.
2. Developed a problem where heating wouldn't come on. Could only get it to switch on when boiler was on to heat water - then it switches off when water is hot.
3.Tried fitting a new synchron motor. No difference!
4. Tested microswitch and found the switch for the heating is working, but valve somehow isnt' switching it on.
5. Put in a tiewrap as a wedge to put pressure on CH microswitch when valve moves, and heating now comes on. Nice warm house!
6. Big problem! Water also heats up when heating is on - even when the water is turned off at the timer. Also, even though the tank stat is only set at 60, it's getting very very hot!
We've checked for loose wobbly bits in the motorised valve - screws for microswitch were loose and now tightened. Otherwise, what would cause the valve to not move around enough? And why would water and CH get mixed up?
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