Adding a pump to boost hot water pressure...surry flange?

[deadboyfriend]

Hello everyone,

It's a common problem on here and i've spent some time reading so think i'm up to speed.

Essentially our hot water pressure is useless, so i got hold of a Grundfos 15/90 pump to give it a bit of extra kick.

I fitted it today and stupidly didn't think about the expansion pipe that overflows into the cold water storage tank in the loft, so now when i turn the tap on, all the extra pressure from the pump just goes to filling up the tank in the loft....yes....i feel very silly. I can't believe i didn't guess this would happen!

Last year we had a new hot water cylinder fitted and the guy who did it added a surrey flange.

Currently i've just cut into the hot water coming out the top if the cylinder and inserted the pump. To fix the problem, i was going to move the pump to be above were the expansion pipe connects via a 't' joint, but i think this will just cause the pump to suck in air.

Should i now change the whole configuration so that everything comes off the pipe that comes out the side of the surrey flange and just have the pipe out of the top as a vent/expansion?

Thanks in advance for your help?

Simon

 

[twgas]

why was the surrey flange fitted? it's not normal practice to just fit because the cylinder is being changed.
can you post some pics of the pipes and pump you've fitted?