C/H pump on return

[foggy]

In my existing system I have gravity hot water and pumped heating. As seems to be normal, the open vent is tee'd off the connection into one side of the cylinder coil, and the cold feed is tee'd into the other connection to the coil. The pump is on the return, about two feet from the boiler.

Now if I wanted to change to a fully pumped Y-plan system for more controllability of the hot water (but keeping the same boiler), I know I'd have to alter the cold feed and vent to be the first things tee'd off the supply and return. But all of the diagrams I've seen showing Y-plans assume the pump to be fitted in the supply side, between the vent and the three-port valve. Moving the pump would be a bit of a problem as it is located under the floor and there's not a lot of room.

My question is - would the pump be ok to stay on the return, after the returns from the cylinder and rads but prior to the (new) cold feed, or would this cause problems with water being forced up the cold feed into the tank? If it would, I'll probably leave it as it is until the boiler needs replacing. Unless anyone can come up with a cunning plan...

Thanks!

 

[45yearsagasman]

View media item 32248If you have enough room in the airing cupboard then try to achieve this configuration. Remove the pump from where it and bridge the gap left.
There are other ways to configure pipework,but with a cold feed and vent by the cylinder this is what I would consider. The diagram shows S Plan, but you could easily fit a 3 Port Mid Pos valve instead of the 2 valves shown.

 

[onlyfitidealboilers]

 

[45yearsagasman]

Great post

 

[onlyfitidealboilers]

 

[foggy]

Thanks, 45yearsagasman - I'll have a look and see if there's enough space in the cupboard. I'll have to shift the C/H supply pipe around a bit, but that shouldn't be too much of a problem.

Now I wonder if there'd be room for a Magnaclean as well. Or a Spirotech...