I was a little concerned about the gas pressure at my cooker hob so decided
to test exactly what was happening before deciding whether to call a CORGI
engineer or Transco/British Gas as I do not want to get fobbed off by either
as I like to understand what is happening first.
We had a new condensing boiler fitted about 4 years ago by British Gas - a
large one badged by BG but probably a
Worcester Bosch 40 HE Plus with a slightly higher heat output spec. They
upgraded the gas supply pipes to 28mm from the meter to allow for pressure
drops while running. Our gas cooker T's off this somewhere in 15mm I
believe. All working fine!
Two years ago we had a new gas meter and regulator/governor fitted as part
of the gas mains upgrade in our road in plastic.
Last week during very cold weather I measured 22mBar static pressure using a
conventional water gauge at the gas meter test point. When
the boiler fires up the working pressure drops to anything between 16mBar
and 18mBar still at the gas meter depending on how large a flame is being
by the central heating system. I therefore detect about 5mb drop just at
I called British gas this week when the temperature was very much warmer and
within the hour. He showed me his water gauge readings (all at the gas
meter as before)
and they were totally different from mine last week. The static pressure
was 24mb and the
working pressure was 19mb when the boiler was running full.
He got the same sought of drop in pressure I had found (i.e about 5mb drop)
but from a much
higher static pressure.
He seemed a bit officious and said mine was his third similar visit that day
and he blamed CORGI engineers for taking wrong readings. He thought my
governor was the best brand new type available and should be correct. He
said if the working pressure was below 19mb he could adjust the governor (I
thought they were not supposed to do that).
After he had gone I re-tested it myself and got very similar readings. I
found the static pressure was even up to 25mb today and I confirmed his
19mb working pressure.
I think we were both right on the different days as I had measured it low
last week when the only thing that had changed was the ambient temperature
which was much colder then. Does the gas pressure change much with
weather temperature and overall demand in the street?
I cannot get them to do anything today so am stuck with what I have got
for the time being. Everything seems to be working OK.
What do others think.