central Heating Pump Size

[D_Hailsham]

using a raytek IR thermometer gun.

IR thermometers can give misleading readings as the temperature displayed depends on how 'shiny' the surface is that the gun is pointed at. The guns are usually calibrated using a 'black body' with an emissivity of 0.98. If you point it at used copper pipe with a dull surface, which has an emissivity of approx 0.78 it will under read the temperature by about 20%.

The safest way of getting consistency is to wrap some black insulating tape round the pipe and read the temperature off the tape. You also need to be as close to the pipe as possible as the gun averages the temperature over a fairly large area; think of a torch beam.

 

[agsaunders]

using a raytek IR thermometer gun.

IR thermometers can give misleading readings as the temperature displayed depends on how 'shiny' the surface is that the gun is pointed at. The guns are usually calibrated using a 'black body' with an emissivity of 0.98. If you point it at used copper pipe with a dull surface, which has an emissivity of approx 0.78 it will under read the temperature by about 20%.

The safest way of getting consistency is to wrap some black insulating tape round the pipe and read the temperature off the tape. You also need to be as close to the pipe as possible as the gun averages the temperature over a fairly large area; think of a torch beam.

Hi again, sorry for delay. i changed the pump and house is heating up better. I have sighted the flow from the boiler to the three way valve and pump and its 28mm. After that its 22mm with 15mm spurs to each radiator. The flow and return to the DHW is all 28mm. I have noticed 5 TRVs appear to be on the return line at the furthest radiators from the boiler. on the ground floor.Would that have any effect ? They have arrows on them.

I have been through the balancing again and have a flow of 70 deg and return of 55 deg ( measured with clip on thermometers and IR gun..within 2 deg c of each other).Boiler seems to stay on the same load and is not modulating down. I have spoken to a few heating engineers amongst the suggestions are fit bigger radiators in the living room which is the coldest place ( 38m2 with two myson double panel double convectors 1140mm x 500mm. Fit 28mm piping throughout. Insulate floors, Change to a pressurised header,Zone the upstairs and downstairs which is feasible and my view is go back in time to 1988 when the house was built and start again. Unfortunately i cant do that.