Hi all,

I apologise now if that has been covered in the newsgroup before, but
I did a search and couldn't find a similiar post with the same
symptoms.

I have a combi boiler which I think is "short cycling" Once the rads
have to got to required heat, the boiler will fire for 40 seconds and
then shutdown for 4 mins. All rads have a TRV apart from the bathroom
rad which is the bypass radiator. None of the TRV's are set to full
and the only thermostat is on the boiler itself.

The only reason I started looking at the CH system was due to the fact
that my gas bill seemed very high compared to same period last year.

The other symptoms , which I don't know whether it is related, is that
I have bleeded the bypass radiator every fortnight and a substantal
amount of air has been vented. All other radiators haven't required
bleeding and all get hot.

The only change to the system in the last 12 months was that a
radiator was removed and replaced whilst a wall was being plastered.
The system was drained and refilled at the same time.

I read in an earlier post that there may be to much by-pass flow could
be a cause of short cycling?

Any advice or guidance would be much appreciated.

Freddie