central heating not coming on , changed 3 port valve

[bowcourt]

Hi all, my heating is firing up ok but when selecting central heating the boiler does not fire up. I changed the 3 port valve for a horstmann valve but still have the problem, when you select central heating the valve moves to just past the mid way position but not fully across, if you then pull the override lever fully across the boiler fires up and you get heating. I thought it might be a faulty valve so tryed another identical valve and it does exactly the same. Any ideas ?

 

[Bamber gaspipe]

It`s probably your programmer/clock but then you say your heating is firing up o.k.? please clarify.

 

[EliteHeat]

1) Incorrect voltage from HW off to the M/V. Usually grey wire.
2) Incorrect/no voltage from room thermostat to white M/V wire

 

[Bamber gaspipe]

1) Incorrect voltage from HW off to the M/V. Usually grey wire.
2) Incorrect/no voltage from room thermostat to white M/V wire

No good talking like a Dalek, it`s a programmer or Roomstat fault is it not?

 

[bowcourt]

Incorrect voltage from HW off to the M/V. Usually grey wire.

i did have a guy come round and he fitted a new control box , all worked fine when he left but next day i noticed the boiler was switching on when both central heating and hot water were switched to the off position, switched the power off then on again and this resulted in the problem i described earlier ?

 

[Bamber gaspipe]

Incorrect voltage from HW off to the M/V. Usually grey wire.

i did have a guy come round and he fitted a new control box , all worked fine when he left but next day i noticed the boiler was switching on when both central heating and hot water were switched to the off position, switched the power off then on again and this resulted in the problem i described earlier ?

Then he is a pillock, get someone in who has an idea. Mate was it? Pay the consequences fellah.

 

[bowcourt]

Incorrect voltage from HW off to the M/V. Usually grey wire.

i did have a guy come round and he fitted a new control box , all worked fine when he left but next day i noticed the boiler was switching on when both central heating and hot water were switched to the off position, switched the power off then on again and this resulted in the problem i described earlier ?

Then he is a pillock, get someone in who has an idea. Mate was it? Pay the consequences fellah.

no was a heating engineer , the old control box had micro switches behind the connections and he said he hadn't come across this before and replaced it with a standard connection box.

 

[Bamber gaspipe]

He wasn`t, you have paid for & got a substandard service...tell it to the Judge my friend

 

[EliteHeat]

It's the dalek here. Do you have a multi-meter at all?

 

[bowcourt]

It's the dalek here. Do you have a multi-meter at all?

hello mate , yes i do.

 

[EliteHeat]

OK, with all of the thermostats set to maximum, measure the following:-

HW on / CH off - voltage on orange wire
HW off / CH off - voltage on grey wire
HW off / CH on - voltage on grey wire + white wire
HW off / CH on - voltage on white wire

 

[Bamber gaspipe]

It's the dalek here. Do you have a multi-meter at all?

No offence Elite, you know ya stuff.

 

[EliteHeat]

It's the dalek here. Do you have a multi-meter at all?

No offence Elite, you know ya stuff.

None taken

 

[bowcourt]

OK, with all of the thermostats set to maximum, measure the following:-

HW on / CH off - voltage on orange wire 240v
HW off / CH off - voltage on grey wire 70v
HW off / CH on - voltage on grey wire + white wire 40v
HW off / CH on - voltage on white wire

240v

i have put the readings above, didnt know what u meant on the grey wire + white wire reading so the reading i put down was the grey wire hw off/ ch on.

 

[bowcourt]

OK, with all of the thermostats set to maximum, measure the following:-

HW on / CH off - voltage on orange wire 240v
HW off / CH off - voltage on grey wire 70v
HW off / CH on - voltage on grey wire + white wire 40v
HW off / CH on - voltage on white wire 240v

240v

i have put the readings above, didnt know what u meant on the grey wire + white wire reading so the reading i put down was the grey wire hw off/ ch on.