Low Water Pressure

[FRAN1870]

The cold water tank is currently in the airing cupboard.... assuming I don’t have room for an unvented tank + accumulator then does the following plan sound feasible.

I could put a bigger cold water tank in the loft to increase the gravity fed hot water pressure, and then have a break tank with pump on the cold feed?

That will increase the flowrate to whatever I need it to be as long as the tank is big enough to cope with demand.

If I had a pumped higher flowrate then would this feed two showers and not drop when the toilet is flushed?

 

[ivixor]

There's a reason that millions of houses were built with a loft tank and vented hot water cylinder! It works whatever the incoming water pressure.

 

[dilalio]

I could put a bigger cold water tank in the loft to increase the gravity fed hot water pressure, and then have a break tank with pump on the cold feed?

If you have the room in the loft and do not intend to have a loft conversion in the future, then the best way forward would be 1 or 2 CWSCs in the loft and a HWC in the airing cupboard, all sized to meet peak demand for both hot and cold draw offs via shower pumps such as Quartz digital showers which can be located in the loft also.

Break tanks and accumulators are best located on the ground floor, basement or garage where space is often at a premium.

 

[FRAN1870]

I have three loft voids one of which has already been converted. Still got plenty of space though.

Having a cold water storage tank would need to be pumped direct to the shower is that correct? So an isolated feed to the shower?

The loft space and plumbing is such that it would be a right ball ache to do that?

Would it be so possible to pump water to the en-suite as a whole? Assuming the en-suite toilet and shower won’t run at the same time?

A pumped accumulator tank on the ground floor might be an option.... the kitchen is quite big so could hide one in a cupboard if they aren’t too noisy?

 

[dilalio]

You can pump the whole ensuite if required, but not with a digital shower pump which is controlled via an electronic switch.
A twin impellor pump such as a showermate would be required and this has to be appropriately sited (usually in airing cupboard down low next to cylinder). You'd also hear the pump every time the loo is flushed.
You'd ideally need a pump for each shower and these would need their own dedicated feeds for both cold and hot, from the CWSC and the HWC.
Accumulator needs a loading pump to charge it and these have noise and space overheads - look at my photo above: the pump is on the floor between the megaflo and accumulator and we put it on a concrete slab with fibre underlay below to try and restrict operating noise. The whole lot was eventually hidden inside wardrobe space with sliding doors.

 

[wwwebber]

Would it be so possible to pump water to the en-suite as a whole? Assuming the en-suite toilet and shower won’t run at the same time?

Yes you can as long as the tank is big enough and you have a decent pump that will cope with demand.

Are you intending to pump to an existing leccy shower ? or a new thermostatic mixer ? I ask because you cant just pump the cold to a mixer.

The unvented cylinder idea is dubious here. It too depends upon cold water pressure so in effect you are running two showers (one leccy, one mixer) and are sharing the pressure on three fronts.

Ideally you would have a large maybe 210l cold water tank in the loft and a large hot water tank (not sure how big yours is) - maybe the same size and both are pumped (using a twin impeller pump) to your showers / baths leaving all others (toilets, sinks etc) to run off your mains so as to reduce interruption.

 

[FRAN1870]

That’s what I have hot water wise ... sorry but I’m not sure what size it is.
The cold water tank above it is aboit 2ft x 3ft x 2ft

 

[FRAN1870]

Picture

 

[wwwebber]

That’s what I have hot water wise ... sorry but I’m not sure what size it is.
The cold water tank above it is aboit 2ft x 3ft x 2ft

My old cwt was about that size but it was only about 80l. I recently went through the whole water pressure / showers malarky and looked into this in detail and 80l would last about 5 - 7 mins pumped to a mixer before it ran out. I actually ended up with a 210l unvented indirect cylinder which works great for me but it wont for you as you want to run two showers simultaneously and your water pressure is naff.

If it were me I would do the following (happy to be challenged on this) :-

• Remove your existing cwt
• Put in a 210l cwt in the the loft
• Install a larger hwc maybe 210l too as you should now have plenty of space
• Pump both hot (from hwc) and cold (from cwt) to the whole en-suite using a good twin impeller pump
• Install a mixer shower running off the pumped hot and cold feeds
• When you re-do the other shower then this can be converted to a mixer too if you run off the same pumped hot & cold (yes it should cope if your pump is good enough)
• For the rest of the house leave as much as you can running off the cold water mains

Sounds expensive but I would say much cheaper than an unvented cylinder + pressure vessel etc

 

[FRAN1870]

I would need to scrap the electric shower I have in the en-suite and probably re-tile too ... aaaww man!!

All this on top of a new kitchen

 

[wwwebber]

A stop gap could be a large CWT in the loft feeding one or two electric showers (not mixers) via gravity. This may be enough pressure on its own but if not you need to either pump it using a single impeller pump or have a leccy shower with an integral pump (ie power shower type thing).

I say stop gap as I don't like leccy showers - if you're ok with them then this might not be such a stop gap for you. And quite cheap too - just make sure your cwt is large enough !!

 

[FRAN1870]

I don’t like electric showers either but I don’t think I’ll have enough head to run an electric shower from gravity? The tank would only be about 1500 above the shower? 0.15bar?

Would have to pump it I guess.

Will an Accumulator tank not deal with it?

 

[wwwebber]

I don’t like electric showers either but I don’t think I’ll have enough head to run an electric shower from gravity? The tank would only be about 1500 above the shower? 0.15bar?

Would have to pump it I guess.

Will an Accumulator tank not deal with it?

An accumulator will do it but I do know that installing a large accumulator will be far more expensive than a pump + cwt combination - looked into this too myself. Also you need to oversize your accumulator as it contains a lot of air.

Again as an absolute minimum it would be a new CWT + pump solution in my opinion.

 

[FRAN1870]

I could make space for a full height kitchen unit? Like a fridge freezer housing? the place in mind is also right next to the main drop from the first floor to the ground floor so hooking it up would be less involved?

How can I calculate the size I need?

 

[wwwebber]

I could make space for a full height kitchen unit? Like a fridge freezer housing? the place in mind is also right next to the main drop from the first floor to the ground floor so hooking it up would be less involved?

How can I calculate the size I need?

You referring to CWT size ? then you need to do some calcs in terms of litres per sec output from your shower(s) and then take into consideration CWT re-fill rate whilst you're using it etc