Fully pumped conversion - Relocating Pump & CH flow

[adlees]

Good afternoon.

First off, I'd like to thank everyone on DIYnot forums, the forum has been my one stop shop for all things DIY in my new house and it has never failed to provide all the knowledge I required. So thanks for that.

On to my question, and also my first post as a member.

After initially trying to get an expert in to do this conversion for me, I have decided to tackle it myself due to the "experts" not even turning up, and even if they did, they never got back to me with prices or availability.

I currently have your typical pumped CH and gravity DHW and was toying with the idea of going to C-Plan, but as many people on here have suggested, if you're breaking in to the pipes you may as well have a go at going fully pumped.

My CH pump is currently next to the glow-worm back boiler, so was thinking of moving this up to the airing cupboard. From here, I'd position it so that it would pump the existing gravity flow to either the cylinder coil, or CH circuit by way of a couple of '2-port' motorised valves, S-Plan. I would of course position this after the vent/expansion tee to allow direct vent access for the boiler and fit an automatic by-pass valve between after the pump (but before valves) and the existing gravity return.

From there, as there is no CH circuit close by, I would need to go under the floorboards, identify a CH flow, and tee in to the circuit. I could then utilise the existing return for both circuits. At this point I'd have two feeds and would need to isolate where the original pump was supplying water to the CH circuit, would I be able to just cap off where the old pump was to complete the circuit?

Any pointers or help would be much appreciated!

Thanks

Andy - an ambitious DIYer

 

[adlees]

Bump

Anyone shed some light on this? The weekend's a comin'!

 

[adlees]

Anyone? Surely someone can help?

 

[boabcelt]

What you are proposing sounds ok to me. Remember to fit the pump after the open vent and the cold feed. Ideally these should be within 150mm of each other (not always practicable). I always fit bleed points on the pipework in the cylinder cupboard.

 

[adlees]

The vent is currently off the boiler flow, and cold feed is in cylinder coil return. Is it advised to move the cold feed to the cylinder flow, before the pump? Would a automatic bleeding valve where old cold feed was to bleed any air in the coil be suitable?

Thanks

 

[45yearsagasman]

If it looks something like this you should be ok.The MI's will indicate which tappings to use on the boiler. View media item 32248

 

[dcds4]

id keep the pump by the boiler, cut in a 2 port on each return, auto bypass then join them together before the pump, assuming your ch pump is on the return?

 

[45yearsagasman]

That's ok on a floor standing boiler but a pain when on a back boiler.Best to fit pump in A/C IMO,but its your call.The OP was thinking of moving the pump to the A/C in his original post.

 

[mysteryman]

I agree with everything here, except that I would use a Y Plan [3 port mid position valve]. Not everyone likes them, but they are better for these reasons:

There is always a port open so that residual heat is utilised [by gravity in this case]
There is only one valve to pay for, fit, and go wrong.
The wiring is no more difficult, although some will say it is.

The first point is highly valid on boilers with pump overrun. It should not be pumped straight back to the boiler via a bypass.