Why is my heating so poor?

[slimwallet]

DP: had hot water off all day with no real difference. The hot water 2 port valve was definitely shut and I am checking the valves to make sure all is as it should be. As the flow and return temps are nearly up to 30degC then I think this must indicate low flow.

Agile. The boiler size of 30kW was what the local company who did the job installed. They do have a good name locally so I really don't know what happened there. I was certainly no wiser so wouldn't have questioned it if I had been asked.

I am going to apply the settings fron snb for tomorrow.

Thank you all for your contributions.

 

[DP]

For poor flow, when boiler fires, flow pipe under the boiler will be at temperature indicated (or close enough) by the display. A meter down stream, it will be cooler. If you can get hold of two clamp thermometers, fit one under the boiler on the flow pipe and second one about a meter downstream.

When boiler fires, observe the temperature on the two thermometers
Poor flow will be indicated by dissimilar readings

If temperatures similar, boiler diagnostics would be a starting point