Gloworm Combi heating outside tap??

[tnarg999]

Does this sound right to you?

A friend of mine is renovating a property and has just paid several thousand pounds for a Gloworm Combi and multi radiator intstall. He wanted to move his outside tap a few feet, so he shut the water off at the stopcock and then drained outside tap. Approx two buckets of very hot water came out of the tap This is an outside cold tap.
Now I am not an expert, but this doesn't sound right to me, but the guy from Gloworm says it's supposed to do that, drainig back down from the boiler.

They also installed 22mm copper to all the Rads stating that you get more flow than 15mm, but surely the heatloss from the pipe surface area would contra this?

Any thought? Thanks

 

[namsag]

No rads work better with 22mm and any additional heat loss would be into building so its not actually lost.
As for tap that sounds very strange does it run cold when turned on and left

 

[tnarg999]

Thanks Namsag,
yes the tap does run cold when left, just a bit weird it is hot to start with.

 

[gas_man_gaz]

is it postioned close to the boiler? it could be drawing some of the warm water what has been sat in the boiler and warmed up by the ch being on