No Central Heating, Hot Water working

[ALCPlumbing]

Try testing voltage coming from programmer when heating is on. It's a yellow wire in with brown from room stat.

 

[stardanny]

You will need a multi meter to test whether there is voltage coming out of stat terminal 3 when turned on. If there isn't, check voltage coming out connector block where brown wire for room stat is.

Daniel.

 

[gsdaheley]

ok thanks.

so my tester shows the yellow wire from the programmer as 220v when disconnected. when connected to the brown wire of the stat, it shows nothing.

Would appreciate any help without multimeter! But if no other option I will pick one up tomorrow.

 

[ALCPlumbing]

Don't disconnect anything. Just turn programmer on and stat up and test at all points along that path to check the voltage. So test voltage at the fifth terminal from left in junction box and then if you have mains voltage there check terminal 3 on the room stat. Then the white from zone valve. Then orange from zone valve. I suspect the motorised valve is at fault but can't understand why u have no voltage at terminal 3 on room stat.

 

[gsdaheley]

so i did as suggested. Along all the points you suggested, the voltage tester showed 12 right the way through to the orange, but no heating.

Not sure if 12v is right as when I connect it to live (220) it starts the motor, valve moves and boiler fires up, but i am a layman

 

[ALCPlumbing]

You should check the wiring at programmer. What programmer is it?

 

[ALCPlumbing]

As a temporary fix till you get an engineer just manually open valve and control by putting hot water on. You may have to turn cylinder stat up though as it will go off when cylinder stat is satisfied. Alternatively link the live from spur to the room stat and just control heating by turning room stat up and down. It will be same as having it on constant at the programmer.

 

[gsdaheley]

Yeah I am aware of the workaround but was looking to sort it properly myself.

Wiring at the programmer seems fine. I should state that everything has been functioning fine for 2 years. The property is a refurb/new build. And all the wires look in good health, no splitting or anything.

 

[ALCPlumbing]

I would assume that the programmer would be sending out mains voltage normally and it isn't. It's a bit odd that it's 12v. You have narrowed it down to programmer though if it's showing 12v at T5 in junction box then that's coming from the programmer.
Sorry I couldn't help more but there's only so much you can do over the internet.

 

[stardanny]

Alternatively link the live from spur to the room stat and just control heating by turning room stat up and down. It will be same as having it on constant at the programmer.

I second that. To see if programmer is faulty.

Put down the tool, have a nice rest and leave it till tomorrow, when you can get a multi meter.

Daniel.

 

[gsdaheley]

I definitely appreciate your help!!

The thing is, like i mentioned before, when I disconnected the yellow wire from the programmer, it measured mains voltage, but drops down when connected to the brown wire of the stat.

I think I will take a rest Daniel. Will pick up a multimeter and get back to it tomorrow.

Thank you

 

[gsdaheley]

Ok so multimeter at the ready and looking for advice! Tried fiddling around with the multimeter and learnt the hard way that I'm not sure how to test...
Would appreciate any help from previous posters or anyone else.

 

[gsdaheley]

Just tried the workaround so connecting Brown wire for stat to live, and heating works when turning stat up. So would that confirm programmer needs changing? Thing that puzzles me is the wire from programmer is showing 220v on voltage tester (not multimeter as I'm not sure what I'm doing with that). Any way of switching wires for hw and ch on programmer to confirm?

 

[stardanny]

As the heating work when stat turned up, it confirm the programmer might be faulty.
Before using the multi meter, please read the instruction first. Using the multi meter, set it to AC volt on multi meter, touch red probe on connector block where yellow wire for heating is, and touch black probe on neutral, take a reading with heating off on programmer ( should be 0v ) then take a reading again with heating on on programmer.

If there no 240v with heating on at programmer, the programmer is faulty.

Please do take care as there is live parts and terminals. And also bin the screwdriver tester, it is unreliable.

Daniel.

 

[gsdaheley]

Thanks for instructions.
You're right, multimeter shows nothing when programmer off and when on. However screwdriver tester is showing 220 when on.
Should I take the plunge on new programmer or is there a way to test by switching CH and HW wires to fool programmer and see if it's wiring or something else? (i.e. when swapped, hot water should stop working if programmer is truly at fault)