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Heating Only not working
Hi,
I can not get my central heating to work in "heating only" mode. I do not know if this has ever worked as I just moved house. (House is approx 15 years old and most of central heating components have been replaced in the past 5 years I believe.) It works fine in "Hot water only" or "both heating and hot water" but when I just turn on the central heating at the programmer nothing happens. The programmer is new (Tempus 7). I suspected the 3 way valve was faulty so I changed this for a new one, (Danfoss Randal H3A) Initially I just fitted the new actuator, but then fitted a new valve with the new actuator. This didn't make a difference. When the programmer is set in "Heating Only" mode I am able to use the manual override switch on the 3-port valve and then the heating comes on. (The water also comes on as the valve is in the mid position when using the manual override switch.) I did start to attempt to make a wiring drawing of the whole central heating electrics, but so far this is proving to be complicated as I can not confirm exactly which cables are which at the junction box in the airing cupboard. One thing I did note is that on the programmer only the outputs for Ho****er On and Heating On are connected. Ho****er Off and Heating Off are not used. Is this significant? Any suggestions where to start looking? Thanks, Matthew |
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In an earlier contribution to this discussion,
Matthew Bailey wrote: Hi, I can not get my central heating to work in "heating only" mode. I do not know if this has ever worked as I just moved house. (House is approx 15 years old and most of central heating components have been replaced in the past 5 years I believe.) It works fine in "Hot water only" or "both heating and hot water" but when I just turn on the central heating at the programmer nothing happens. The programmer is new (Tempus 7). I suspected the 3 way valve was faulty so I changed this for a new one, (Danfoss Randal H3A) Initially I just fitted the new actuator, but then fitted a new valve with the new actuator. This didn't make a difference. When the programmer is set in "Heating Only" mode I am able to use the manual override switch on the 3-port valve and then the heating comes on. (The water also comes on as the valve is in the mid position when using the manual override switch.) I did start to attempt to make a wiring drawing of the whole central heating electrics, but so far this is proving to be complicated as I can not confirm exactly which cables are which at the junction box in the airing cupboard. One thing I did note is that on the programmer only the outputs for Ho****er On and Heating On are connected. Ho****er Off and Heating Off are not used. Is this significant? Any suggestions where to start looking? Thanks, Matthew You have a wiring problem. This configuration *only* works in CH-only mode when the HW-off terminal in the programmer is properly wired up. In addition, the cylinder stat *must* be of the changeover rather than on/off type. [You don't need a CH-off connection] Have a look at the Y-plan wiring diagram in http://content.honeywell.com/uk/homes/systems.htm and bring your system into line with it. -- Cheers, Set Square ______ Please reply to newsgroup. Reply address is invalid. |
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