shower pump

I am fitting a twin pump to my thermostatic mixer valve. Cold tank is in loft and hot is in upstairs airing cupboard. I understand that I can take both hot and cold feeds off exsisting pipework in airing cupboard without any essex flange or the like because the mixer is thermostaticlly controlled. Can anyone confirm this? Now for the main question....Plumbing under floor would mean lifting flooring in 3 rooms. Is it ok to take my outlets from the pump upwards into the loft, along the loft floor and downwards to my mixer valve or would this cause air problems? All pipework would still be more than 230mm lower than the cold water tank as stated in fitting instructions.

dontdiy said:

I am fitting a twin pump to my thermostatic mixer valve. Cold tank is in loft and hot is in upstairs airing cupboard. I understand that I can take both hot and cold feeds off exsisting pipework in airing cupboard without any essex flange or the like because the mixer is thermostaticlly controlled. Can anyone confirm this?

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I don't know where you heard that, but take no notice. If you have read the MI's, they will most probably tell you that the pump will need it's own dedicated supplies. Most MI's have a diagram to follow aswell, but if not, it would be something like this..

dontdiy said:

Now for the main question....Plumbing under floor would mean lifting flooring in 3 rooms. Is it ok to take my outlets from the pump upwards into the loft, along the loft floor and downwards to my mixer valve or would this cause air problems? All pipework would still be more than 230mm lower than the cold water tank as stated in fitting instructions.

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If your tank is raised in your loft, (230mm as you stated) this should be OK. Otherwise you will be needing a negative head pump.

I don't know where you heard that, but take no notice. If you have read the MI's, they will most probably tell you that the pump will need it's own dedicated supplies.

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I got this information off of this site on the page headed "planning a shower"
Perhaps I should mention that only 1 hot kitchen tap can be used at the same time as the shower as all other draw offs are in the same bathroom and the kitchen cold is mains water, and in your diagram as in my MI's show the hot can be taken from the shared feed?

Thanks for your help so far but I'm a little confused now further help would be appreciated.

dontdiy said:

I don't know where you heard that, but take no notice. If you have read the MI's, they will most probably tell you that the pump will need it's own dedicated supplies.

Click to expand...

I got this information off of this site on the page headed "planning a shower"
Perhaps I should mention that only 1 hot kitchen tap can be used at the same time as the shower as all other draw offs are in the same bathroom and the kitchen cold is mains water, and in your diagram as in my MI's show the hot can be taken from the shared feed?

Thanks for your help so far but I'm a little confused now further help would be appreciated.

Click to expand...

Hot and cold supply must both be dedicated to the pump.
Does the MI show a surrey/warix flange? A diagram using one of these can give the impression that the main hot dist pipe and the pump supply pipe are shared - but they aren't!
Alternatively you could take a 90 deg tee from the hot dist pipe set at 45deg from the cylinder exit point, halfway between the cylinder and the tee to the vent.
Or you could use an essex flange in the side of the cylinder.
Also make sure that the dedicated cold feed to pump is set at least 1" below the cold feed to the hot cylinder where it conects to the cistern.

The pipe work can go up and over to the shower (through the loft?), make sure the system is fully primed before you put power on the pump.