DIYbanter - View Single Post - Central Heating

wrote:
Hi - I'm looking for advice, please.

We have an oil fired boiler and recently I've noticed that our heating
doesn't seem to be working properly. Normally, the boiler will fire
when the heating comes on and it will go off when the house has reached
the required temp (around 20 degress as controlled by our room
thermostat) - usually within 30 - 45 minutes. The radiators normally
begin to feel warm within 10 mins of the boiler firing. What I'm
seeing at the moment is that (occasionally - maybe three or four times
a week) the heating will come on and the boiler will fire up as normal.
However, the radiators do not get hot. The boiler continues to fire
for as long as the heating is on, but the radaiators do not get warm.

Another occasional problem is that when the heating and water come on
at around the same time in the morning, the heating may work but the
water does not get hot. I assume this is probably related?

We had a plumber come out last week and he inspected the system. He
said the electronic valve is fine and he re-mounted the pump as he said
it had been fitted on an angle, which is incorrect. He also vented the
pump, having confirmed it's working okay. Although the system now
seems quieter, we're still having the intermittant problems mentioned
above.

I suspect we have an intermittant problem with the pump. As well as
being concerned that the system isn't working as it should, I imagine
that we're using far more oil than necessary as the boiler is
continuing to fire with little or no effect? Or am I misunderstanding
what is happening here?

Any advice gratefully received.

Thanks - Paul.

The most likely problem is the 3 port valve, less likely is the
controller that controls it, or the wiring to it. Metering the
controller output or valve input will tell you which.

For peace of mind I'd check the boiler isnt boiling, as if it is there
would be a danger (plastic header tank boiling and collapse). Its
unlikely.

NT