Downstairs heating only working when upstairs is on

[rich19754]

Very likely a wiring fault... Usually is.

Greys do not go in with oranges in terminal strip... Because... They should only be connected electrically... When the microswitch in the power h

Put the greys together and the oranges together... As I said above "commoned"

If you had 4 x 2ports you'd have 4 greys in together and 4 oranges together!

Ok thanks will do that. Is there than another grey in with the oranges that feeds the boiler? I think I have wired 2 greys the wrong way round

 

[Harry Bloomfield]

Intermittent, usually means the microswitch failing, but your fitting a new head would seem it ought to fix that. Which leaves an intermittent connection or wire.

 

[rich19754]

Should there be one grey in the terminal with the oranges (not a grey from the valves) that sends the live to the boiler?

 

[Johnmdc]

Both grey wires should be in the same terminal connected to permanent live and both orange wires should be in a different terminal connected to the boiler switched live feed which is the other grey wire (not from either valve).

 

[Johnmdc]

As had been suggested the downstairs valve might be stiff and not opening enough to activate the micro switch.

 

[Johntheo5]

This schematic may help, may have been posted allready above??.

 

[dilalio]

"Ok thanks will do that. Is there than another grey in with the oranges that feeds the boiler? I think I have wired 2 greys the wrong way round"

Yes. Potientallly, it could be a grey wire that takes the 240V from the commoned oranges, to the boiler!

It all depends on what cable the installer used or found in the wall, back to the boiler... Colours only only matter for the 2 port valves tbh... Other cables may use any core... Depending on the installer.

One of the reasons why lots of electricians can't wire up heating controls... it ain't paint by numbers!

 

[Johntheo5]

If you are happy the the valve head grey& orange wires are terminated correctly then depending on the valve manufacturer, simply opening the valve manually and latching it open will fire the boiler, a Honeywell won't, but a EPH or Danfoss will, not sure re Myson or any others.

 

[rich19754]

Hi all - the issue is all resolved, it was all my fault as I had wired the new valve head incorrectly (put the grey into the same as the orange) - thanks very much for all your help,

 

[dilalio]

Hi all - the issue is all resolved, it was all my fault as I had wired the new valve head incorrectly (put the grey into the same as the orange) - thanks very much for all your help,

Glad you got it sorted.
As said... It's usually a wiring error!
Makes it more difficult to sort as a visiting engineer when customer has "had a try" themselves

 

[Johntheo5]

Easiest way to avoid errors is to change one wire at the time, remove one old...replace with one new etc.

 

[rich19754]

Easiest way to avoid errors is to change one wire at the time, remove one old...replace with one new etc.

Yeah I did intend doing that but there were so many wires in the terminals I had to remove some to get the new ones in - I was rushing it as well. School boy error for sure but grateful for the help on here

 

[dilalio]

but there were so many wires in the terminals

 

[rich19754]

LOL - I should have used Waygo’s as got loads in the shed

 

[Harry Bloomfield]

Yeah I did intend doing that but there were so many wires in the terminals I had to remove some to get the new ones in - I was rushing it as well. School boy error for sure but grateful for the help on here

They don't make it easy, with so many wires jammed into unmarked connectors.