Vaillant combi- DHW fine, no CH

[billposter]

Can't find my earlier post regarding my Vaillant VCW-GB-242-EH
(or 282?)

Just to say I am no expert on boilers.. i re filled it; its now reading a healthy 2+ bar; nice and quiet in operation

No idea how to get CH to work tho hot water is working perfectly.

There is no wall thermostat or control(missing?), just the control on boiler

The temp gauge doesnt seem to work or maybe it would if CH came on?

Previous owner says it was fine but as it hasnt been used in more than yr could this be a factor? I feel it is something simple..i hope

Any thoughts on prob would be greatly appreciated

 

[LUNAT]

HI

go to vaillant website and look for users instruction

 

[petit_pablo]

Does the boiler fire in ch mode?

Temp guages often dont work on these relics it would show temp in hw mode.

As long as the boiler is firing then i believe the wax capsule to be at fault

 

[billposter]

Cheers for replying-

I did have a brief look at the Vaillant site- didnt realise my boiler was on it- will look again, thanks


When switched on the setting for both DHW/CH it still fires for hot water; fuses all look ok too.

Where is wax capsule situated? Excuse my ignorance..

Will

 

[Gasguru]

2 Bar is way too high ....only fill to 1 bar MAXIMUM.

The boiler doesn't have a wax capusule (they are used on an older variant).

When the heating is turned on with the thermostat/timeclock/switch on the front panel does the boiler do anything? ie do you hear the pump running?

 

[billposter]

Yikes, didnt realise 2 bar was too high- the red 'hand' is at 1.5 and the max point looked to be 3 (round dot)

Nothing happens when switched to dual /continuous setting (only comes on with hot water)

could it be blocked?

 

[Gasguru]

With a heating demand the pump should start up. Are you sure there is no time clock/thermostat fitted. Have a look at the wiring going into the boiler. If you have more than a Live/Neutral/Earth there must be some external controls. Ive found thermotats hidden in the backs of kitchen cupboards, in ceiling voids etc. One thermostat was in the kitchen cupboard of the downstairs flat.

 

[billposter]

Hmm.. I think the thermostat has been removed(?)- I think I can see where something was fitted as there are holes in the wall. I removed the panel at the bottom of boiler and there is only live/neutral/earth.

I'm beginning to think the boiler has moved location.

Should i buy a thermostat or clock and fit it?

 

[petit_pablo]

The boiler doesn't have a wax capusule (they are used on an older variant).

Getting my vcw's confused

 

[Gasguru]

Isolate power to the boiler.

Remove the two screws holding the lower gray panel on.

Remove the single screw holding on the black terminal cover at the lower edge of the control box on the left.

Pins 3 & 4 should either be bridged together (if no external controls are fitted) or will connect to the room stat/timeclock. Pin 5 is a Neutral if the room thermostat requires it.

 

[westbrom]

As the main man Gas guru says this sounds more like a controls problem than a boiler fault.

The roomstat to simplify it is basically a switch, it sounds like someone has removed the roomstat so basically you have nothing to switch the boiler on in CH mode....as gg says check for a bridge at the terminals

 

[billposter]

Isolated boiler, connected 3 and 4 up, switched back on,

hey presto.

Bar went down to 1.5 (to the red marker setting). And the temp gauge works, up to 50 now.

Do I still need to take bar down to 1?

I think I owe someone a bottle at least.

 

[Gasguru]

The red marker is adjustable and normally set to about 1 Bar. It indicates the COLD pressure setting the system should be at. ie the white needle (showing the system pressure) should be at around 1 with the boiler off and the radiators COLD. When the heating is on and all radiators HOT the pressure should ideally not be more than about 2 Bar.

I suggest you drop the pressure down to 1 and carefully check the pressure does not rise too much when the rads are hot.

 

[DP]

If you search, you will find plenty on this boiler.