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www.ultimatehandyman.co.uk Forum Index -> Plumbing Forum
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wokeye
Junior Member
Joined: 04 Oct 2008
Posts: 6
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 Posted: Sat Oct 04, 2008 12:42 pm Post subject: Heating Will Not Work But Hot Water Does, Please Help.. |
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| I have a pretty old heating system that I want to get replaced affter this winter, but would like to try and repair it if at all possible. The system is a Thorn EMI back boiler, hot water cylinder upstairs a header tank in the loft, and a 3 way honeywell motorised divertor valve. The water is working fine. However when I select heating the boiler starts but the I am getting no heating. I have looked at the way valve and pump which is located underneath the hot water cylinder. The valve is not opening at all when heating selected on the timer/programmer. The pump also does not seem to be running, as I thought I might have felt some vibration or something from it ? I replaced the syncron motor on the valve last year for a similar fault. Unfortunately it is an old motorised valve so I cannot replace the valve head without breaking the line, so a new valve will be required. Anybody any ideas, is it probably the valve? Just thought that I would be able to tell that the pump is running and I can't. I have tried a spare room thermostat and this has done nothing, although the boiler is running anyway. Thanks for any advice. |
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thescruff
Senior Member
Joined: 10 Mar 2008
Posts: 5665
Location: Bath
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| Posted: Sat Oct 04, 2008 1:12 pm Post subject: |
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Sounds likely to be be the valve
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Scruff |
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wokeye
Junior Member
Joined: 04 Oct 2008
Posts: 6
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| Posted: Sat Oct 04, 2008 3:49 pm Post subject: |
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| I am sure that this is an electrical problem. I was messing about trying a spare old thermostat that I had and the heating came on for a while, i.e the valve opened and I could tell the pump was running. I then switched the electric off again to refit the thermostat into it's housing and it would not work after this. Is there a way to link the thermostat out by any chance? If so which wires would I link together. It has a red, blue and yellow wires connected to different points. I am assuming that thermostat not only starts the boiler but operates the valve and pump, it would appear this way anyway. Please help. |
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thescruff
Senior Member
Joined: 10 Mar 2008
Posts: 5665
Location: Bath
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| Posted: Sat Oct 04, 2008 4:16 pm Post subject: |
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Give me some makes and models on the stat and valve.
Have you got a multi-meter
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Scruff |
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wokeye
Junior Member
Joined: 04 Oct 2008
Posts: 6
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| Posted: Sat Oct 04, 2008 4:29 pm Post subject: |
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| Thanks mate. The valve is a Honeywell Sundial Y Plan 3 position divertor valve it also had this number on it V4073AI039. The stat is an old Honeywell T6160B or its longer number T6160B1004. I have also had trouble with programmers in the past but this was just the boiler not starting that is a Honeywell ST699. I do not have a multimeter but can get one off my brother. Thanks very much for the help it's very much appreciated. |
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thescruff
Senior Member
Joined: 10 Mar 2008
Posts: 5665
Location: Bath
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| Posted: Sat Oct 04, 2008 4:48 pm Post subject: |
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Link 1-3 in the room stat should activate the MV, provided the programmer is calling for htg
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wokeye
Junior Member
Joined: 04 Oct 2008
Posts: 6
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| Posted: Sat Oct 04, 2008 4:53 pm Post subject: |
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| thescruff wrote: |
| Link 1-3 in the room stat should activate the MV, provided the programmer is calling for htg |
Cheers Scruff I will give that a try and let you know how I get on. Thanks again  |
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wokeye
Junior Member
Joined: 04 Oct 2008
Posts: 6
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| Posted: Sat Oct 04, 2008 5:24 pm Post subject: |
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| Thanks for the help Scruff tried that but still no luck. I might have to get somebody out to check it out as I have not got a clue. Could it be the programmer at all? |
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thescruff
Senior Member
Joined: 10 Mar 2008
Posts: 5665
Location: Bath
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| Posted: Sat Oct 04, 2008 7:07 pm Post subject: |
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This is why you need the multi-meter to check the wires out, starting with the programmer.
With the programmer calling for heat there should be power on terminal 1 in the room stat, simple to check, and at the same time confirms any doubt about the programmer
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thescruff
Senior Member
Joined: 10 Mar 2008
Posts: 5665
Location: Bath
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| Posted: Sat Oct 04, 2008 7:18 pm Post subject: |
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Once you have power on terminal 1 room stat, it switches terminal 3, which in turn puts power on the white wire in the zone valve
No Power to Valve - Hot Water Only (Port B Only)
240 V on White Wire - Hot Water & Heating (Port A & B)
240 V on White & Grey Wire - Heating Only (Port A Only)
240 V on Grey Wire only - Valve is held in last port of call
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Scruff |
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wokeye
Junior Member
Joined: 04 Oct 2008
Posts: 6
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| Posted: Sat Oct 04, 2008 7:40 pm Post subject: |
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| Thanks Scruff I will need to get a multi-meter. The stat is wired as follows I hope this is correct. Red wire - 1, Blue - 2, Yellow - 4. I am not that sure what you mean about the wires to the valve. Thanks for the great advice very much appreciated |
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thescruff
Senior Member
Joined: 10 Mar 2008
Posts: 5665
Location: Bath
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| Posted: Sat Oct 04, 2008 7:53 pm Post subject: |
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But the yellow should be on terminal 3 ?????????
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