VCW T3 25/1

[ChrisR]

One of the many boilers I've never done much with, except heave em off the wall.

Got to go to a T3 25/1 which "doesn't work"
In an office loft (!!)

They are uncertain whether pilot stays on or not. They think it did, but it's out now.
Would this boiler put its pilot out on overheat for any reason - did they have fans ever?
A girlie said the pilot was on but it just "clicked a lot "

I don't have the Vail tc for it. Does a Universal fit?

Any model-specific funnies I should look at first if it isn't the pilot?

GV/operator obviously a poss. Never worked out much about how they work though I still have bits from one in the shed.

 

[namsag]

The sine 25 is conventional flued. Black rubber over heat stat on right hand side of control box towards rear. universal doesn`t fit need proper one. If pilot drops out you would usually just press green button and relight(and it will light but signal not always received from t/couple) but there is a switch assembly behind the buttons that doesn`t always reset and you need to push red button in a couple of times to reset

 

[ChrisR]

Thanks, I'll detour to pick up a tc.

 

[Agile]

The T/Cs rarely fail ! I dont think I have ever needed to change one.

The electromechanical assembly behind the red/green buttons more often fails mechanically or contacts on it are dirty and do not allow the TC to deliver enough current to the magneto coil.

Its quite a complicated boiler and unlike any other in its operation.

Only other amusing oddity you need to know about is a mechanical interlock on the gas valve operated by differential pressure derived from the system flow.

Tony

 

[ChrisR]

Thanks - I won't detour to pick up a tc!

Looks ike I'd better take the manual with me

 

[ChrisR]

Primary flow switch not moving much - thrust penknife in and got a free beard singe.

Pump capacitor marked 3uF measured 0.5uF so connected an old one across it and boiler works.
Pump rattly though so I'll get another. Big thing, are those heads available separately? Extra long too, do normal length extenders go in there? Normal vented pump is much cheaper than V's.

You were right is isn't a "Sine" - name on label covers several models.
And I would have taken a few minutes looking for the overheat reset, thanks!

 

[Agile]

As far as I am aware you have to buy the WHOLE pump which includes the back part as a Vaillant spare and are well over £100.

I knew it was useful to mention the flow interlock!

Tony

 

[ChrisR]

Yes, thanks.
Raises general question, applying to other boilers with odd pumps too. (eg Ari SX-20)
Is it always OK to substitute a pump, for a different one of the same head? I suppose so.

 

[Softus]

As far as I am aware you have to buy the WHOLE pump which includes the back part as a Vaillant spare and are well over £100.

Sorry - I'm confused. Do you mean Vaillant ® ?