My boiler fires and heats to 80 degrees C for a short time, then cools back down again quickly. The pipes near the boiler heat up, but only as far as the first radiator downstairs and this rad doesn't get hot. Other downstairs rads are cold. Upstairs rads are reasonably warm, but not as hot as they should be.
Looks to me as the water is not going round the circuit as the downstairs return pipe is cold and upstairs return pipe is only a little warmer. This seems to leave 2 options:
a. Pump is broken
b. There is an airlock
Option a
Pump is vibrating and having removed the centre screw on the Grundfos pump the impellor is going around. Therefore appears to be working, but could be slow or have a damaged impellor?
Option b
Is this possible? I had a similar problem recently and when I bled the radiators upstairs the system worked fine.
I assume the upstairs rads are warming through convection only.
I have considered replacing the pump and draining the system right down and refilling it. Does one of these ideas seem sensible? Should I try anything else? Would either idea cause me any major problems? (I am competent DIYer and electrical engineer)
Looks to me as the water is not going round the circuit as the downstairs return pipe is cold and upstairs return pipe is only a little warmer. This seems to leave 2 options:
a. Pump is broken
b. There is an airlock
Option a
Pump is vibrating and having removed the centre screw on the Grundfos pump the impellor is going around. Therefore appears to be working, but could be slow or have a damaged impellor?
Option b
Is this possible? I had a similar problem recently and when I bled the radiators upstairs the system worked fine.
I assume the upstairs rads are warming through convection only.
I have considered replacing the pump and draining the system right down and refilling it. Does one of these ideas seem sensible? Should I try anything else? Would either idea cause me any major problems? (I am competent DIYer and electrical engineer)