"Clever" controller for central heating?
Discussion
Ferg said:
Hobzy said:
Minor hijack, but if your condenser was fitted without a room thermostat, how simple is it to add one of these wireless jobbies?
Very easy, but if a condensing boiler is fitted without a room thermostat it contravenes regulations.skilly1 said:
skilly1 said:
So Can I replace this for a Honeywell CM927 - if so is it easy? Are there just two wires I need to connect to the new controller?
Any one know how to remove the cover on this? Can't see any screws or holes to push clips in...Ferg said:
oldcynic said:
So is there a controller that allows variable temperature settings through the day, is capable of optimisation, and will also manage the water heating including the holiday programming?
Not that I've seen for a while, I have to admit. Normally just a programmer set to constant on the heating side and a programmable room thermostat on the wall.Hobzy said:
Ferg said:
Is it a combination boiler? If not how many motorized valves do you have?
Yes combi - ecotec plus 824. Thermostatic valves on all the rads bar two upstairs I haven't got round to doing yet.Tempted by this thread, I've bought a CM927, and I'm trying to work out how to wire it up and then how the controller should be set to make best use of it. I currently have the controller and thermostat below. The controller needs the hot water to be set to come on at the same time as the heating - otherwise it just pumps cold water around the radiators.
Presumably I'll need to set both the heating and hot water to 'Continuous' and let the CM927 control the temperature?
The current thermostat, which I'm going to replace with the CM927 relay box, has three wires - the red appears to be live, the blue neutral, but what about the yellow?
Actually I think that I've worked it out - the Red goes to L in the relay box, the blue to N and the yellow to B (boiler presumably), with a link added between L and A. Can anyone confirm?
I won't be popular tomorrow if I mess the heating up
Presumably I'll need to set both the heating and hot water to 'Continuous' and let the CM927 control the temperature?
The current thermostat, which I'm going to replace with the CM927 relay box, has three wires - the red appears to be live, the blue neutral, but what about the yellow?
Actually I think that I've worked it out - the Red goes to L in the relay box, the blue to N and the yellow to B (boiler presumably), with a link added between L and A. Can anyone confirm?
I won't be popular tomorrow if I mess the heating up
smn159 said:
The controller needs the hot water to be set to come on at the same time as the heating - otherwise it just pumps cold water around the radiators.
Sounds like your system isn't wired correctly at the moment. I had similar problems and ended up tracing all the wiring and writing up a circuit diagram with the help/motivation of a friend. We then googled central heating circuits, although I later found these were in the boiler installation manual as well, worked out it was a Y-plan in my house, and worked out two seperate wiring mistakes. It would seem that not all plumbers are good with electrics. I'd hazard a guess that your 3-way valve and/or pump is wired wrong, but it's not my line of work so don't take my word for it.The biggest clue as to whether you've got a Y-plan or S-plan is the number of 3-way valves (ie 1 or 2)
Until you work out what's wrong at the moment you'll not get anywhere with making your system efficient and making best use of your new controller.
oldcynic said:
smn159 said:
The controller needs the hot water to be set to come on at the same time as the heating - otherwise it just pumps cold water around the radiators.
Sounds like your system isn't wired correctly at the moment. I had similar problems and ended up tracing all the wiring and writing up a circuit diagram with the help/motivation of a friend. We then googled central heating circuits, although I later found these were in the boiler installation manual as well, worked out it was a Y-plan in my house, and worked out two seperate wiring mistakes. It would seem that not all plumbers are good with electrics. I'd hazard a guess that your 3-way valve and/or pump is wired wrong, but it's not my line of work so don't take my word for it.The biggest clue as to whether you've got a Y-plan or S-plan is the number of 3-way valves (ie 1 or 2)
Until you work out what's wrong at the moment you'll not get anywhere with making your system efficient and making best use of your new controller.
Regarding the CM927 wiring. I don't fit them myself, but I would imagine the base station requires a permanent live to keep it in contact with the wall unit so the red wire from your old thermostat may not be suitable since it's switched from the time clock. You could make it permanent at the boiler/junction box end, but there are issues with running the boiler for hot water then, I think.. (it's a bit early for gravity systems today!)
smn159 said:
Ferg said:
If it's a gravity hot water system the programmer should be set to always heat the water when the central heating comes on. It sounds like the programmer is the wrong type.
Thanks - what would the rough cost be of converting to fully pumped? Is it a worthwhile change?Edited to add.....
What a cracking 2a! I had one in the dim and distant... before Land Rovers became rebodied Range Rovers.
Edited by Ferg on Saturday 15th January 09:59
Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff