Vailliant VCW-sine 18 T3W - Need Help!!!!

[Scoobyd69]

Hi All,

I've recently moved into my first house and have an old Vailliant VCW-sine 18 T3W combi boiler. Been there about 1 year and have noticed a tiny leak from one of the pipes and looks like it has been happening for a while as the pipe is now covered with limescale (I will try and attach a few photos)

Nothing was wrong with the system until recently when i noticed that the system had stayed on and not switched off with the timer, or the room thermostat.
Could this mean there is a fault with the timer or is this due to the pipe's?

I have located the spare parts guide online and found the following parts:

08-1336 - connection tube cpl.
08-3742 - cold water tube
98-1506 - packingring

But i still have the same problem about the timer, at the moment i have to turn the system off by the mains to stop it as it seems to be by passing the timer and the room thermostat has no use now.

Any help would be appreciated and if anyone knows where i can get the part's that would be great.

 

[Bunnyman]

These were qualit in there day stopped manufacture in 1986. If urs is leaking from the chrome bit in the middle (which is the normal place for the symptoms u describe) that's the water valve 011198 or 011156 either will do, the gland leaks an the valve sticks an the boiler thinks a tap is open an dumps ht around heating, however looking at ur photo that leak is from the gland on the flow switch at the top an tracking down the back, sorry but u will not find a flow switch anywhere they r obslete

 

[Dan Robinson]

Email me and I can give you details of a Vaillant specialist in London who can keep this venerable bird working. Can't guarantee he covers your area though.

 

[Bunnyman]

Maybe dan but unless he's a magician he won't find a flow switch? Me an 831 busted a gut to get one the last one i got from mr Combi 2 years ago 141014 if anyone can track one down ? Beware companies on line say they have stock take ur money then don't have any ....This is the bloke I recommend in London not sure if he's the same as your man? http://vaillantservice.co.uk/VAILLANT/Vailliant_Home_Boiler_Repairs_Servicing_Faults.html

 

[Dan Robinson]

Nah, my man is called Andy - he's ex-Vaillant too though.

Missed the flow switch bit (I've had enough of those today ).

 

[gas112]

Bunny got a mate who mentioned a while back he still had a couple of brand new flow switches much are they worth if he still has them should see him in next week or so as he is on hols just now

 

[Scoobyd69]

Thanks guys,

However i believe its the connection tube & the cold water tube that are the problem not the flow switch, as there doesnt seem to be a problem with that. the leak seems the come form the nut

 

[Bunnyman]

u asked for advice from the experts mate take it. y would a leak from apipe cause the symptoms u have!!! change the pipes if u want it wont make an iota of difference

 

[Scoobyd69]

I appreciate everyones advice, i only said about the pipes as a gas engineer friend of mine said it was the nuts on the pipes not the flow switch itself.

 

[Agile]

I dont seem to be able to view those photos at a reasonable size.

Based on what I can see, it could well just be the pipe connection.

Usually I find that there are at least two or three faults on those boilers.

Whilst I am happy to repair them, most want the bigger job of replacing with a new boiler.

Tony

 

[Bunnyman]

Yes tony but that leaks bin there for a year! It's not goin to cause the prob he stated! As u know leakin water section gland or leaking flow switch gland or wax stat will b the problem, absolutely no use mendin the leak if it won't solve the problem on an old one like this ...

 

[The831Bunny]

From the very low res photos it looks like the leak is nothing more than the washers needing replacing on the cold connections to the flow switch. These usually leak when the domestic expansion vessel loses charge and a non-return valve is present on the cold supply. As to the boiler staying on, as Bunnyman says, its a water section problem.

The flow switch could be leaking from the top and running down, but impossible to see that from the resolution of the pics i'm afraid.

 

[Agile]

OP, are you running the boiler in the DHW preheat mode?

Tony