- 18 Oct 2007
- Reaction score
That would imply a flow rate of approx 0.7 litre/sec which, using the screwfix graph, would need the pump set to 3. But you say this is with the pump set to 2. Stranger and stranger.With the aluminium measurement plates for the IR thermometer I get a consistent 6 degree figure.
Have you had a chance to check the temp drops with the pump on all three speeds and all rad valves open? Don't have the HW circuit open when you do this.
I am a bit suspicious of the aluminium plates used for measurement. I can see why you are doing it - to provide a consistent emissivity. Try wrapping some black insulating tapes round the pipe for a few inches and measure off that. Due to the size of the area over which an IR measures - it's like a torch beam - you have to be almost in contact with the pipe to get an accurate reading.