Vaillant Combi VCW Sine 18 - is stuffed

[zxcvbnm14]

Hi - My girlfriends Vaillant boiler recently stopped working after we bled radiators and turned temp up on thermostat. There was no pressure in the boiler...not sure waht was going on there.

Anyway we refilled the boiler with water to 2 bar and then bled radiators again adn beld air from the valve up the top of the boiler. No more air, and pilot light and burners are all working.

BUT Hot water only lasts for a few secs and isnt boiling hot, the radiator closest to the boiler is HOT, 2nd radiator hot, 3rd radiator luke warm, 4th radiator COLD.

Can somebody tell me how to get the thing working properly again.

Thanks very much in advance for any help you could give me.

Cheers

Wazza

 

[kevplumb]

check the pump is running and vented
check the diverter valve is moving
check the prv isnt passing could be where your losing pressure

 

[zxcvbnm14]

The pump is running as i can hear (and feel) the water going into the system. But how do I check to see if it is vented??

How do I check if the diverter valve is moving? I thought diverter valave is something I have to check if I get HW and not CH (or vice versa) but I get both just not much of it.

Sorry about the dumb questions.

 

[weargas]

you may need to vent any air from the dhw heat exchanger. it's a small alloy jacketed cylinder inside the boiler with a venting nut atop. it also sounds like a problem with your wax capsule.

 

[kevplumb]

undo the big silver screw in the midddle
water may be HOT
check the prv (overflow) usuall goes outside
if the diverter isnt moving the little hot water you get could just be whats in the heat exchanger
run the hot water with the heating off and see if the flow pipe gets hot

 

[kevplumb]

oh yet another sucsess ???????????????????????