Shower Pump Query

[chestercity]

I have fitted a few before but not with the same issue I encounter...can anyone advise please.
Its a bungalow. There are two showers and its a gravity fed system. Whereas pressure was acceptable, though not good, I have updated the bathroom and shower and installed a Trevi concealed valve. I have put a ceiling arm coming down and the added height and pipe run have reduced the flow to gentle rain.
The pipes are run in the loft and drop down from above. Trev valve prefers to be fed from below (not sure why it matters?)
What I would like to do is feed one pump from the T that takes the flow from hot and cold that goes to the first shower. The run is 22mm and reduces down to 15mm down to the valve. However the pump instructions state that it should ideally be situated at base of hot cylinder. This would involve a lot of hassle-separate feeds from cold and hot coming down from the loft.
Can I do what I propose from the pipes already in the loft, or will I hit issues?
Hope the above makes sense...

 

[Phill Peck]

Only with a negative head pump.
And even then not ideal pumped showers should have dedicated supplies
Base of airing cupboard is best

 

[chestercity]

I fitted a negative one in a flat we have and it was fine and easy because thwe cold tank was i the bathroom cupboard and hot feed came up from below. Has been working for 3 years without fault.
So I have to run separate and new pipes for this then I assume. Brink a cold feed down from cold tank to the airing cupboard. Do I T off the hot as well. I assume that the feed going up already for the existing pipework could be used, but I'm uncertain what flange it has fitted. Its coming from the centre of the hot tank, which I believe is correct-to avoid air locks etc?

 

[Madrab]

Couple of pics would help. If you have a flange, are there 2 pipes coming out of the top of the HW cylinder connection? One heading out the side of the connection the other out the top?
Dedicated feeds for the pump is ideal & a large enough Cold Cistern and HW Cylinder to feed 2 showers if pumped. Expect a drop in pressure if the other shower is used at the same time. Make sure you bleed the system properly.

 

[chestercity]

One pipe only out of the top. One out of the side, which I am assuming was added to supply the showers. I can ring the tech line of. Tr are times when you wish you had left things well alone...

 

[Madrab]

Nope, the pipe out the top looks like an ordinary supply and vent for your whole hot water system. You need to add a flange to the cylinder that has a tube that dips into the hot water to avoid drawing in air bubbles.

You need a Surrey/Warwick(x)/York flange or a separate tapping included as part of the cylinder to give a dedicated air free supply.

 

[chestercity]

Yes, what I thought, unfortunately. What about the one out of the side though? Its a hot pipe. I thought it may supply shower hot supply?
And I need to take a cold supply directly from Cold tank...

 

[dilalio]

How is your water heated? immersion or through coil in cylinder? Photo of the whole cylinder and connections would be useful! Mainly one of the side outlet (Essex flange) that you think feeds the shower!

 

[Madrab]

I wouldn't usually expect to see a flange down that low, that could be the feed/return for the coil inside the cylinder that heats the water. As Dilalio mentions a wider look at the cylinder and its pipework would help.

 

[chestercity]

Thank you for your comments.
Its heated with heat exchanger, so I see what you mean by the outlet on the right.
Its hard to get a decent photo but will try shortly. Especially the flange.
I'll switch current shower on and see if that pipe feels hot.
I think you are probably both right. Unlikely that I have necessary flanges.
I see Salamander make an S flange that's easy to install. Maybe way forward.
I'll upload another image.

 

[chestercity]

More shots but I am sure your right...its not dedicated shower outlet.

 

[dilalio]

Those two connections are to the coil inside the cylinder and not for shower feed.

You'd be best of getting a Surrey flange which will be easier to install and means you won't have to drain cylinder so much and drill into it!

 

[Madrab]

Any of the top fitting flanges will suit you, Surrey (Salamanders type) /Warwick(X)/York. If taking a dedicated feed from the cold, as far away as possible form the current feed in the cistern and if running 2 showers simultaneously, pump size dependent, then you may want to consider a 28mm feed to the HW cylinder and cold feed. Cold cistern size is also worth a thought, again depends on how the showers will be used.

 

[chestercity]

Thank you both.
I shall follow your recommendations. I shall most probably just feed one shower this way and leave the other one as is, as it works well enough.
The hot feed to the bath runs at floor level whereas the shower feeds are taken to the loft and then dropped down. I believe this was done because its difficult to run the pipes under the floor-although a deep void, the chamber if you like, under the bathroom is blocked up and I would need to take out some block work to get to it.
Just to confirm my routing of the water, I would take it down from Cold tank to Cupboard with hot tank and would then be pumping back up and then dropped down into the shower from above (down to the shower valve.) I will use 22mm where possible, though I believe pump outlets are only 15mm. This will be going up to roof and along about 3 meters before dropping. Will the pump do that distance in 15mm efficiently enough I wonder....
I'll clear it with the pump makers (Salamander). They extend your warranty if you follow their advice...!

 

[Madrab]

What model of Salamander pump is it? Is should handle the distance and height without an issue. That's all fine for a single shower. Keep the pipes below the level of the cold cistern and minimise the numbers of bends/rises. If the shower will run, albeit badly, once all plumbed in then that will allow the circuit and pump to be primed, if not you may need an air vent at the pipe runs high point.