I have bought a house fitted with a Vaillant combi boiler.
The unit has been extensively serviced by a vaillant engineer who fitted
many new parts.
I recently replaced the top up tap which meant draining the system.
Since restarting the system the CH seems to work only intermittently.
The hot water is fine.
The CH when it comes on, starts the process, pumping, clicking, etc, but
only fires up sometimes after a little while. This is with timer or manual.
It would seem that there is air in the system.
The vent on top is open. The rads have all been bled.
Is there some thing else I can do?
Thanks Peter Brown

On Thu, 30 Sep 2004 11:11:33 +0100, Peter Brown wrote:

I have bought a house fitted with a Vaillant combi boiler.
The unit has been extensively serviced by a vaillant engineer who fitted
many new parts.
I recently replaced the top up tap which meant draining the system.
Since restarting the system the CH seems to work only intermittently.
The hot water is fine.
The CH when it comes on, starts the process, pumping, clicking, etc, but
only fires up sometimes after a little while. This is with timer or manual.
It would seem that there is air in the system.
The vent on top is open. The rads have all been bled.
Is there some thing else I can do?
Thanks Peter Brown

Which model?
Try turning the heating thermostat up?


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Have you bled air from the pump?
There is an air bleed screw on my Vaillant that should be loose so that
trapped air can escape from the pump.

Graham

"Ed Sirett" wrote in message
news
On Thu, 30 Sep 2004 11:11:33 +0100, Peter Brown wrote:

I have bought a house fitted with a Vaillant combi boiler.
The unit has been extensively serviced by a vaillant engineer who fitted
many new parts.
I recently replaced the top up tap which meant draining the system.
Since restarting the system the CH seems to work only intermittently.
The hot water is fine.
The CH when it comes on, starts the process, pumping, clicking, etc, but
only fires up sometimes after a little while. This is with timer or
manual.
It would seem that there is air in the system.
The vent on top is open. The rads have all been bled.
Is there some thing else I can do?
Thanks Peter Brown

Which model?
Try turning the heating thermostat up?


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

On Thu, 30 Sep 2004 23:51:40 +0100, Ed Sirett wrote:

On Thu, 30 Sep 2004 11:11:33 +0100, Peter Brown wrote:

I have bought a house fitted with a Vaillant combi boiler.
The unit has been extensively serviced by a vaillant engineer who fitted
many new parts.
I recently replaced the top up tap which meant draining the system.
Since restarting the system the CH seems to work only intermittently.
The hot water is fine.
The CH when it comes on, starts the process, pumping, clicking, etc, but
only fires up sometimes after a little while. This is with timer or manual.
It would seem that there is air in the system.
The vent on top is open. The rads have all been bled.
Is there some thing else I can do?
Thanks Peter Brown

Which model?
Try turning the heating thermostat up?

Further thought: it sounds much more like an ignition problem than a water
one.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html