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Hi All
We have an oil fired Boiler, Tank in the loft and Hot Water tank in the airing cupboard with a Honeywell ST9400A control and HCW80 and HC60NG remote thermostat.
For a while the Hot Water was not coming on. We had to fire up the Heating if we needed Hot Water.
I swapped the motorised head of the valve from the Heating to the Hot Water and it worked fine, so i thought i would buy a new synchron motor. I have just fitted the new motor but now the Hot Water won't switch off. When the power is on the MV activates and closes the switch which then switches the Hot Water on even though all of the controls and HC60NG are off. When i turn the power off the valve does close (and when i have turned it by hand i can feel the valve moving inside) so i don't think it is ceased open. Is it a wiring issue? or the Tank Thermostat? (i have turned the thermostat on the tank down but it has no effect. I can hear the click at over 70 degrees even though its only set to 55)
I am at a loss of what to try next. Should I keep it turned off for now?
Any help is much appreciated.
thanks :)
 
Hi All
We have an oil fired Boiler, Tank in the loft and Hot Water tank in the airing cupboard with a Honeywell ST9400A control and HCW80 and HC60NG remote thermostat.
For a while the Hot Water was not coming on. We had to fire up the Heating if we needed Hot Water.
I swapped the motorised head of the valve from the Heating to the Hot Water and it worked fine, so i thought i would buy a new synchron motor. I have just fitted the new motor but now the Hot Water won't switch off. When the power is on the MV activates and closes the switch which then switches the Hot Water on even though all of the controls and HC60NG are off. When i turn the power off the valve does close (and when i have turned it by hand i can feel the valve moving inside) so i don't think it is ceased open. Is it a wiring issue? or the Tank Thermostat? (i have turned the thermostat on the tank down but it has no effect. I can hear the click at over 70 degrees even though its only set to 55)
I am at a loss of what to try next. Should I keep it turned off for now?
Any help is much appreciated.
thanks :)
Update.
When i swap the MV over from the CH to HW (as they are next to each other). Everything works as it should with the controls on the HW (using the CH MV)
BUT with the HW MV on the CH i would expect it to act as it did previously and switch the CH on and keep it on, but instead it doesn't activate the heating at all and the Manual override slide is loose. Not sure why it acts on way on one valve then differently on another?
 
So you’ve moved the wiring over aswell

sounds like a bad head
 
Could be the timer, cylinder stat or just a bad 2 port valve easy way to test if you have 240v on the brown to the hot water port valve
 
Yep
 
Thank you for the help on this. I have sorted the Head issue out and it now switches the water on great. But we now have the issue that was the original problem before all of this and that is the HC60NG box keeps turning off (no green light) but the hot water stays on. If we don’t switch the heating off at the wall to reset everything the hot water just stays on all day. I am guessing I need to buy a new HC60NG unit and swap it for the old one?
 
Have you replaced the batteries in the stat ?
 
Quick update. The water came on as the timer asked it to, but again the hot water has stayed on even though the timer and the HC60 box have gone off. It is so hot upstairs now as the excess hot water has gone to the Rads upstairs.
 
Was the green light on the receiver?
 
Are both port valves closed eg shut ?
 
Wired wrong or prog faulty do you have 240v on the brown to the hot water valve ?
 
Programer sticking needs changing if you remove it from the base plate you should loose your 240v on the brown hot water

I’m guessing the programmer is set to all off ?
 
If your water is getting excessively hot, it would indicate that the HW valve is being by-passed, the rubber ball in the valve could have perished as they tend to do, they do not last forever.
 
Thanks for all the suggestions. This morning I got up and the hot water was on even though it was not programmed to come on until later and the HG60 box was off too. So it does suggest the program box or HG60 issue?
the valve does close and when I control it manually it heats up and cools down ok so doesn’t suggest anything mechanical. I think I will look at a replacement HG60 panel first then a programmer panel if that doesn’t fix it?
 
So I bought a new HG60 unit and have fitted it. Switched on the power and seconds later the hot water started up again. Without the new unit on or it being timed to come on. I have a new control unit coming tomorrow. This is driving me mad. The only way to stop it coming on is to switch the whole heating off at the wall and then turn it on when we want hot water, then remember to turn it off later otherwise it stays on all night. Any help is greatly appreciated. Thanks
 
Need to test no point in throwing parts at it
 
I have tried all the tests I can think of and nothing seemed out of the ordinary so trying this now. No one seems to have any other answers - desperate times!! My wife is giving me so much grief I am doing anything at this point! Lol
 
Don't know if fitting a new complete motorized head instead of just the synchron motor would make any difference or not. In the meantime suggest fitting (again) the motorized head from the CH to the HW and wire it up by removing/using the wires from the "old" HW head, let the wires disconnected from the other actuator and see what happens.
 
Disconnect the orange wire and see what happens or what shouldn't happen.
I disconnected the orange wire and turned the power on. The MV still moved around and engaged the switch but the boiler didn’t fire up (I guess that’s what the orange wire does :))
 

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Don't know if fitting a new complete motorized head instead of just the synchron motor would make any difference or not. In the meantime suggest fitting (again) the motorized head from the CH to the HW and wire it up by removing/using the wires from the "old" HW head, let the wires disconnected from the other actuator and see what happens.
When I swap the heads over and the wiring then the same thing happens. But before I changed the wires over I tried just swapping the heads. So basically to get the Hot Water is now controlled by the Heating side of the programmer - Doing this solves the issue - it works as it should - to get the MV to operate I had to turn on the HG60 and the programmer on and then the MV kicked in as normal to turn the hot water on. Brilliant! But then the other valve opens the heating valve and turns the Heating on without being asked! So must be a wiring issue? Even though I haven’t moved any wires around before the issue started? I posted a pic of the wires in the post earlier
 
Don't know if fitting a new complete motorized head instead of just the synchron motor would make any difference or not. In the meantime suggest fitting (again) the motorized head from the CH to the HW and wire it up by removing/using the wires from the "old" HW head, let the wires disconnected from the other actuator and see what happens.
When I swap the heads over and the wiring then the same thing happens. But before I changed the wires over I tried just swapping the heads. So basically to get the Hot Water is now controlled by the Heating side of the programmer - Doing this solves the issue - it works as it should - to get the MV to operate I had to turn on the HG60 and the programmer on and then the MV kicked in as normal to turn the hot water on. Brilliant! But then the other valve opens the heating valve and turns the Heating on without being asked! So must be a wiring issue? Even though I haven’t moved any wires around before the issue started? I posted a pic of the wires in the post earlier
 
I have taken the fronts off all the controls but the Lee is still 240v on the orange and the grey cables and when I turn the far right switch on or off this turns the hot water on and off without any controls. Is there a wire I need to move etc?? I have tried it with the MV head from the heating valve and re wired it but it does exactly the same thing so can’t be the head as the Heating head works fine when it’s on the Heating.
 

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Have you checked the wiring at the ST9400A controller in case there is a extra permanent live connected by mistake to the "HW Off" which is used for a Y plan configuration or something along those lines.
 
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You have a bad port valve or one permanently calling do you have any voltage on the browns on the port valve wires ?
 
Need to test no point in throwing parts at it
i have taken the program unit and the HG60 module off. The power is on. you should make out the numbers behind the wires. with the black wire on the tester in space 3, I have 240v in lines 1, 7, 8 and 0. The HW is on and won’t switch off. Even though the controls are removed.
 

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Have you checked the wiring at the ST9400A controller in case there is a extra permanent live connected by mistake to the "HW Off" which is used for a Y plan configuration or something along those lines.
I notice that this is not how it says it should be wired on the back of the program box
 

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