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Post by DIYDafty on Feb 16, 2022 16:10:49 GMT
Still working with my neighbour - honest guv its not me !
He's replacing his old mechanical room stat with a powered one so needs a neutral.
Other side of the wall is the HW cyclinder and easily accessible MV. S plan system.
Now we haven't tested this yet but if you were to turn off the HW at the programmer, would you normally still have a neutral at the MV ?
P.S. There is no junction box anywhere - I've never seen such a mess of cables (e.g. 3 cables going through the cylinder stat !)
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Post by battle1066 on Feb 16, 2022 17:44:40 GMT
Still working with my neighbour - honest guv its not me ! He's replacing his old mechanical room stat with a powered one so needs a neutral. Other side of the wall is the HW cyclinder and easily accessible MV. S plan system. Now we haven't tested this yet but if you were to turn off the HW at the programmer, would you normally still have a neutral at the MV ? P.S. There is no junction box anywhere - I've never seen such a mess of cables (e.g. 3 cables going through the cylinder stat !) That old school room stat was designed to have a neutral in it so how has it functioned without it? The MV will have a neutral which should not change status by any of the programmer switch functions although will not be there when the fused super is turned off as the fused spur is double pole. |
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Post by DIYDafty on Feb 16, 2022 20:11:05 GMT
Still working with my neighbour - honest guv its not me ! He's replacing his old mechanical room stat with a powered one so needs a neutral. Other side of the wall is the HW cyclinder and easily accessible MV. S plan system. Now we haven't tested this yet but if you were to turn off the HW at the programmer, would you normally still have a neutral at the MV ? P.S. There is no junction box anywhere - I've never seen such a mess of cables (e.g. 3 cables going through the cylinder stat !) That old school room stat was designed to have a neutral in it so how has it functioned without it? The MV will have a neutral which should not change status by any of the programmer switch functions although will not be there when the fused super is turned off as the fused spur is double pole. Perfect - thanks Battle! Btw, the stat has a single cable with 3 core and earth (old colours). The red is the permanent live and when the stat is turned right up yellow goes live. When right down blue goes live. No neutral unless (quite possible) I've made a big mistake |
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Post by battle1066 on Feb 16, 2022 21:31:31 GMT
That old school room stat was designed to have a neutral in it so how has it functioned without it? The MV will have a neutral which should not change status by any of the programmer switch functions although will not be there when the fused super is turned off as the fused spur is double pole. Perfect - thanks Battle! Btw, the stat has a single cable with 3 core and earth (old colours). The red is the permanent live and when the stat is turned right up yellow goes live. When right down blue goes live. No neutral unless (quite possible) I've made a big mistake DD right your right you’ve got everything spot on - the only neutral is the connection at the motor none in the thermostat (me being lazy and not looking at it sorry). |
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Post by tomplum on Feb 16, 2022 22:26:55 GMT
Is it me ? in battles stat pic, i see a live, a neutral, switched live ( yellow) and earth with red sheathing. the stat will need a neutral to work the 'anticipator' in the stat which, anticipates whether the temp is raising or falling,  |
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Post by battle1066 on Feb 16, 2022 22:39:04 GMT
Is it me ? in battles stat pic, i see a live, a neutral, switched live ( yellow) and earth with red sheathing. the stat will need a neutral to work the 'anticipator' in the stat which, anticipates whether the temp is raising or falling,  In DD job it’s wired like so Attachment Deleted |
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Post by DIYDafty on Feb 16, 2022 22:45:26 GMT
Is it me ? in battles stat pic, i see a live, a neutral, switched live ( yellow) and earth with red sheathing. the stat will need a neutral to work the 'anticipator' in the stat which, anticipates whether the temp is raising or falling, I haven't got in front of me as that's his house but I'm pretty sure when we tested it the yellow was switched live but the blue was the "unswitched live". i.e. the blue was live when the stat was turned right down. |
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Post by tomplum on Feb 16, 2022 22:54:46 GMT
OK I'm not well up with modern wiring so I'll bow down, please post the outcome so we all learn from it  |
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Post by battle1066 on Feb 16, 2022 22:57:29 GMT
Is it me ? in battles stat pic, i see a live, a neutral, switched live ( yellow) and earth with red sheathing. the stat will need a neutral to work the 'anticipator' in the stat which, anticipates whether the temp is raising or falling, I haven't got in front of me as that's his house but I'm pretty sure when we tested it the yellow was switched live but the blue was the "unswitched live". i.e. the blue was live when the stat was turned right down. Your set up will be as per that drawing - two lives away from it for motor on motor off satchwell motorised. |
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Post by DIYDafty on Feb 16, 2022 23:12:08 GMT
I haven't got in front of me as that's his house but I'm pretty sure when we tested it the yellow was switched live but the blue was the "unswitched live". i.e. the blue was live when the stat was turned right down. Your set up will be as per that drawing - two lives away from it for motor on motor off satchwell motorised. The strange thing is the MV he has (now a honeywell) only has a single brown live cable (apart from its neutral, earth and also apart from the pump/boiler circuit that it switches). In other words if there is juice going down that single brown wire, the MV will start up and if there isn't it won't. Which begs the question why was the blue wire in the stat ever needed ? |
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Post by dickpuller on Feb 17, 2022 7:40:19 GMT
Oh Dafty, Dafty!! What the fuck are you doing??!!
CH wiring, like lots of Wiring Circuits, have a Common Earth & Neutral.
As said the old R/S should have a Neutral.
But going by the wire colours is always the wrong thing to do.
Get a Auto Range Multimeter & check it out.
As my dear old dad would say, who worked on 33,000 Volt Overhead Lines by the way!! ‘With electrics, a little knowledge is dangerous’!!!
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