vaillant 20/1 T2W CH starts and stops

[Bunnyman]

Ok this is how it works the pd valve is basically there to prove the pumps working the pin pushes out when the pump runs an operates the gas valve so the flames are not going out an then pd valve pin going in but the pd valve pin is goin in an causing flames to go out. Does hot water all work all ok an prob is just with ch

 

[gorselands]

sorry Bunnyman just realised we were on to page 2. Pin only goes back in on CH when flames die, It does not go in and cause flames to die.

 

[gorselands]

yes, the HW works ok only prob with CH

 

[Bunnyman]

Ok pull the aluminium cover off flow switch put heating on see if the little brass arm is making the rh switch an is any heat going down ch flow pipe an do u have any dripping taps at all

 

[gorselands]

No dripping taps. Removed multiplug from flow switch before removing Aluminium cover. Put it back again and now nothing is working HW or CH. so can't test at moment.

Have started looking for old hot water bottle and puncture repair kit!

 

[The831Bunny]

Oi Bunnyman thats my van!

As mentioned in previous posts

1. Is Hot water working all OK? If so problem is flow switch related.
2. Are external controls giving 240V to terminal 4? Link T3 to T4 if in doubt.
3. Check and double check you don't have a dripping tap or hot water leak.
4. Do switch levers on flow switch under aluminum cap rise after a minute of turning the heating on and the flow pipe (lhs) get hot?

If still no heating replace the flow switch complete as the wax capsule is now obsolete. If you have never changed this before then I'd think about changing the boiler, it must be at least 22 years old.

Bunny[/url]

 

[Bunnyman]

Hello 831 boy! Is it ur van or mine? 1987 eh them were the days when trainin was proper in the fatherland

 

[The831Bunny]

Deffo mine. Still got the import plates on. Taken in a Stourbridge hotel car park!

Yeah those were the days. No targets or bonus to cloud your judgment

 

[Bunnyman]

Mmm mine had german plates also but I think u sent me this pic u want me to delete it ??

 

[gorselands]

Thanks The 831 Bunny. 1,2 & 3 seem ok, so is looking like the replacement flow switch. Will probably try to replace as I have two boilers side by side running 21 rads; big old house!! They flue up the chimmney - now illegal and the cost of replacing the two with pipework would be prohibitive. Apart from that I dont have sufficient space on an outside wall to place them. There doesnt seem to be one boiler that would replace the two in terms of output unless a commercial one. Then it would need to be zoned and probably have an extra HW tank. Any ideas. Will call it a day now as I've been at it for 14 hours. Will try again tomorrow and check on No 4. if you are around the help is so appreciated.

Mike

 

[Bunnyman]

Good luck mate flow switch still available bit awkward to fit

 

[Vaillantman1997]

vM

 

[Bunnyman]

no mate who r u ? ours was 15 call out an £3 every 15 min lol

 

[gorselands]

Just an update. Put new diaphragm in diverter and checked pipes. Flow valve seems to be operating micro switches. Another engineer came out and said pipes were getting too hot. Definitely blocked/scaled heat exchanger. They are still available @£200.00. I have taken it out and flow seems fine but hard to tell whats in the rad bit. I have ordered Fernox DS3 but will be Wednesday. In the meantime dressing like a woolly mammoth.

 

[gorselands]

sorry that should read differential valve