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 demanded by the central heating system. I therefore detect about 5mb drop just at the meter.
I called British gas this week when the temperature was very much warmer and they came 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.