Hope someone can shed some light.....
For no reason today, my hot water and heating failed. The boiler
(Potterton Kingfisher) fires up, although the temperature of the flue
gases are much higher than normal, and runs for about a minute before
shutting down - possibly overheating. The pump is ok (have removed and
checked & only 3 months old), and if i push the (2 port Honeywell)
motorised valve round with a screwdriver, the pump starts, although
there is a sound like water cavitation as if it can't circulate at
all. The wiring seems ok, but I am not sure where to go next. I
haven't got a lot of money at the moment, so it would be good if
someone could guide me as to where to go next. A plumber is the
absolute last resort!

Thanks

Russell

The pump is ok (have removed and checked & only 3 months old),
and if i push the (2 port Honeywell)

Before we go any further, bleed all of your radiators and any bleed valves
you see elsewhere on the pipework, such as near the pump, boiler and zone
valves.

The symptoms seem to indicate that no water is flowing. How are you sure the
pump is working? Don't be distracted by the fact that the pump is new. The
"bathtub" reliability curve indicates that brand new equipment is less
reliable than stuff that has been installed and working for a couple of
years.

Christian.

"Russell" wrote in message
om...
Hope someone can shed some light.....
For no reason today, my hot water and heating failed. The boiler
(Potterton Kingfisher) fires up, although the temperature of the flue
gases are much higher than normal, and runs for about a minute before
shutting down - possibly overheating. The pump is ok (have removed and
checked & only 3 months old), and if i push the (2 port Honeywell)
motorised valve round with a screwdriver, the pump starts, although
there is a sound like water cavitation as if it can't circulate at
all. The wiring seems ok, but I am not sure where to go next. I
haven't got a lot of money at the moment, so it would be good if
someone could guide me as to where to go next. A plumber is the
absolute last resort!

Thanks

Russell
Does the system have a header tank?
(i.e not a combi boiler or sealed system)
If so the symptoms could mean that your header tank is empty and so there
is not enough water in your system to allow the pump to drive it.
This can happen when the ball valve sticks closed and the water slowly
evapourates.

HTH
Dave R