Mains Water pipe getting hot!

[Savva]

I went to do a safety cert the other day on a Main 30kw Combi. When I called for heat, as well as the F&R heating up, so did the mains supply pipe to the boiler! Had a quick look and the further from the boiler the cooler the pipe...any ideas what's causing this? Thanks guys

 

[macackau]

I went to do a safety cert the other day on a Main 30kw Combi. When I called for heat, as well as the F&R heating up, so did the mains supply pipe to the boiler! Had a quick look and the further from the boiler the cooler the pipe...any ideas what's causing this? Thanks guys

You need to PM one of the mods your gas safe details and then re-post this in the private gas safe forum