Advise on pipework to fit a whole house pump please

[kevin12345]

Hi,
I have decided to fit a whole house pump instead of a shower pump so it boasts the water all over the house.
I have included some more photos of the pipes around the HW Cylinder in the airing cupboard.
I have one 22mm in the side of the tank coming from the 3 port valve
I have the 22mm coming from the top of the HW Cylinder that has a branch going off to the en-suite shower before it gets to the expansion pipe which goes up to the loft tank, but also goes down below the airing cupboard floor.
I also have another 22mm pipe coming out of the bottom of the HW Tank which goes down below the floor of the airing cupboard.
What Iam asking is the correct connection of the hot water pipes that connect to the outlet of the Whole house pump.
I know I have to make a new connection into the HW Cylinder to the feed the inlet of the hot water on the Pump but I'm not 100% sure about reconnecting the hot water back to the Pump Outlet.

Why does the expansion pipe also go vertical down below the airing cupboard floor is it feeding hot water to somewhere else?
What is the bottom 22mm pipe coming out of my tank, the hot water supply for the Whole house? Do I need to cap this off and then reconnect this pipe to the outlet side of the HW Pump?
Do I disconnect the HW Shower pipe that branches off the Expansion pipe and reconnect this also to the outlet side of the HW Pump.
Im I missing something else?
Hope my information is clear, I'm starting to confuse myself.

Untitled

• kevin12345
• 22 May 2013
• 2

Untitled

• kevin12345
• 22 May 2013
• 2

Untitled

• kevin12345
• 22 May 2013
• 2

Untitled

• kevin12345
• 22 May 2013
• 2

 

[SimonH2]

The first thing that comes to mind is that you appear to have very little knowledge of really basic plumbing concepts - so do you really have the knowledge and skills to do the job ?

There are normally 4 connections to the HW cylinder - in the first photo, the two on the die (one with the motorised valve in it) are the connections to the boiler. Don't touch these at all.
There will be a connection (probably the unlagged pipe in the background of the first pic) bringing cold water from the header tank to the bottom of the cylinder.

The pipe you need is the one coming out of the top of the cylinder which is both the hot water feed to "everything" and the vent. It is this that will need to be modified. The downward going branch (with the red handled gate valve) will be the feed for everything but the en-suite shower.
You must keep the open vent as it is.
After the vent pipe branches up into the loft, you need to cut into the downwards branch and that goes into the pump inlet. The pump outlet goes to the pipe going down through the floor In other words, where that gate valve is, you need to insert the pump into that pipe. You will also need to move the branch for the en-suite shower to after the pump if it is to be included.
You should also check that there are no branches coming off the vent pipe out of sight in the loft.

This is all basic stuff, and again I have to caution that you don't appear to have the knowledge to do it yourself.

 

[SimonH2]

You may find http://www.plumbingpages.com/featurepages/HWindirect.cfm helpful

 

[kevin123456]

Thank you for your reply, I have done a bit of plumbing, easy stuff like replacing like for like Bathrooms,radiators etc and changing a motorised valve on the heating but never fitted a pump.

The pipe that was confusing me was the bottom pipe coming out of the HW Cylinder under the motorised valve pipe but if you say that is to do with the boiler, all good.
Yes the unlagged pipe at the back of the HW Cylinder is the cold feed to the cylinder from the Loft tank.
The expansion pipe does not have the red gate valve, that is on the cold water feed from the Loft tank to the rest of the house.
I get everything you say now apart from where I cut the hot water/expansion pipe to feed into pump inlet. Are you saying I need to cut the hot water/expansion pipe in the vertical above the branch coming out of the top of the cylinder or below the branch coming out of the cylinder?

 

[SimonH2]

The expansion pipe does not have the red gate valve, that is on the cold water feed from the Loft tank to the rest of the house.

Ah yes, I didn't see the second pipe - the pictures are a tad dark and fuzzy.

I get everything you say now apart from where I cut the hot water/expansion pipe to feed into pump inlet. Are you saying I need to cut the hot water/expansion pipe in the vertical above the branch coming out of the top of the cylinder or below the branch coming out of the cylinder?

You don't cut the vent pipe at all. You need to cut below the branch, anywhere convenient between it and the floor, and put the pump inline there. To have the en-suite shower run off the pump, you'll need to disconnect it from the tee above the cylinder and reconnect it downstream of the pump.

You must not put any sort of valve in the vent pipe between the top of the cylinder and it's open end above the header tank. It's there for two main reasons :
1) It prevents the cylinder getting pressurised, as could otherwise potentially happen if you closed the feed from the header tank to the cylinder and the cylinder was then warmed up.
2) It prevents the cylinder being sucked in. If you close the feed and then open a tap downstairs, without the vent pipe being there to admit water, the cylinder would be under negative pressure and they can be sucked in (squashed).
1 is a safety issue, 2 is "inconvenient".

 

[kevin12345]

Thank you very much for your clear instructions.

 

[willsgas]

Hi kevin, you should also fit a bypass in case your pump fails, then you can easily revert back to gravity hot water if needed.

 

[Agile]

You are apparently going to put a shower pump on the hot water outlet from the cylinder.

It looks as if you are now going to have unbalanced pressures at the bath.

That may not matter if you don't have any mixer taps.

Tony

 

[SimonH2]

Or it may mean he has less imbalance with taps running off the mains.

 

[kevin12345]

Hi kevin, you should also fit a bypass in case your pump fails, then you can easily revert back to gravity hot water if needed.

fitting a bye pass sounds like a good idea but does the plumbing start to become a bit more complicated?

 

[willsgas]

It shouldn't be any more complicated than not fitting one.
The fact that you have a pipe branching off to the loft makes things slightly more awkward than usual, but its not a big problem.
I would fit a full bore lever valve below the tee of the expansion pipe then a tee for the pump outlet, then below that tee in the shower that runs into the loft.
You will need to follow the manufacturers instructions for the inlet side of your pump as to not have any warranty issues, as some can be quite specific on how they like it to be fed.