Adding 3 metres of 28mm pipe at the end of a 15 metre 22mm run

[helix]

Would it helps if the RGI uses a powerful vacuum machine to suck out the pipe work once it has been disconnected at the meter and the appliances? Just a suggestion.

 

[boilerwoes]

Just thought I would give you an update on this. I had an RGI install a new pipe run - shortest run possible was about 10m of 28mm pipe to the boiler from the meter. This helped the situation a bit, but we were still seeing a pressure drop of more than 2mbar - so we were getting about 17.5/18mbar at the boiler which was surprising (at least to me anyway) as I was expecting virtually no drop. There were definitely no issues with the new pipework.

Do you think any "gunk" could have got into the boiler gas valve to reduce the working pressure?

 

[GQuigley67]

vaillant allow a drop of around 2-2.5mb at their valve so it sounds like your getting a correct reading.