Running power shower pump off normal HW cistern?

Is it possible or a really bad idea? Realise that the tank will empty much quicker than with gravity shower and that I'll probably have to add a timer to the thermostat (at present, CH HW running for two hours a day is perfectly adequate) so that it can re-heat during the morning shower rush.

Thanks, Rob.

Reply to
Rob Nicholson
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What exactly do you mean by "hot water cistern"??

Do you mean the storage tanks in the loft? If so they are not known as "hot water cisterns"!!

If it is the tanks you refer to then yes, that is exactly what shower pumps are for. You will though be surprised at just how quickly your hot water will run out and you'll probably have to double the "on" time.

Reply to
PJO

Hot water cistern/tank (stored hot water) is the way to go with a power shower.

We had to upgrade our copper tank because we emptied it before all 4 of the family had showered to their satisfaction.

Other thing to watch is the cold water tank in the loft. It will empty faster than it can fill when the power shower is running - you usually take both cold and hot (cold feed to the hot tank/cistern) feeds from this tank to provide equal pressure and avoid sucking on the mains :-) We have nearly emptied our loft tank in the past, before the novelty wore off. If it is a goodly size then you should be O.K.

Depends on how many and how long, plus mains water pressure to refill the tank. Like the old school test - water is flowing into the tank at x litres/sec and flowing out at y litres/sec.......

HTH Dave R

Reply to
David W.E. Roberts

Yes, sorry mean the tank not the thing in the loft.

Cheers,Rob.

Reply to
Rob Nicholson

We did the exact same thing- but the header tank emptied too quickly, as other posters have suggested. The water pressure is good, so I got a second ball valve and plumbed that in in parallel, so now two feeds to the tank, and it keeps up nicely. hth Neil

Reply to
Gripper

That's a reasonably acceptable cost - minor compared to cost of refitting the entire bathroom making it bigger at the same time :-)

Thanks, Rob.

Reply to
Rob Nicholson

The existing tank is hopefully a reasonable size - about 5' tall I'd guess.

I'd have to measure it but I get the feeling it's a reasonable size as well compared to some other tanks I've seen.

I'll get my calulator out :-)

Thanks, Rob.

Reply to
Rob Nicholson

Or alternatively fit a much larger coffin tank, if you have the room. I designed our DHW system for a shower pump and although it's taken me a few years to get around to fitting one, it was an absolutely essential fit. The mild "drip, drip" that the English seem to think is acceptable for a shower *really* irritates me.

Reply to
Steve Firth

There are cold water cisterns and hot water cylinders, there is no such thing as a 'hot water cistern'. Mike.

Reply to
Mike Cawood, HND BIT

Unless the plumber makes a stupid mistake, and yes I've seen it happen, cold water out of the hot tapes and hot water out of the cold taps - not to mention filling the WC cisterns !

Needless to say the plumber got the sack, when he next decided to turn up for work....

Reply to
Jerry.

Err... I think you actually mean "cylinder!.

Reply to
PJO

depends - moved into previous house where thermostat on cylinder and on boiler were set way too high, so much hot water passed through the open vent that the cold cistern was definitely a hot water cistern ;-))

Reply to
NikV

How well does the hot water cylinder cope with the demand?

Any worries about the increased load on the ceiling?

Chris

Reply to
Chris J Dixon

The pump is plumbed to two showers: the cylinder is a relatively small one (it's marked 36x16): recipe for failure you may think, but in fact the system copes well. Taking a bath is more likely to overextend the hot water supply than showering. I was pleased that the pump (Aqualisa) can cope with even both showers being used simultaneously. As long as the cylinder is full of heated water, there is no problem with the shower running cold, in normal use. The system is ready for use again only after about 10 mins. We do however have a well lagged cylinder, and the immersion and hot water gas heating is on 24/7.

Neil

Reply to
Gripper

Fine, it's perfectly capable of coping with the entire family + outlaws over Christmas.

No, the original ceiling joists had rotted and head to be replaced so the current ones were sized for the load of the tank. There's a plywood floor beneat the tank. Also the tank is long and thin so the load is spread over a greater area than a standard tank.

Reply to
Steve Firth

Why the immersion? If you have gas heating, the immersion should be an emergency backup only. It costs around 4 times as much to use. If the thermostat is set higher in temp than the gas (or lower in the cylinder), it will even use it in preference to the cheaper source.

Christian.

Reply to
Christian McArdle

I studied the DHW thing for ages before deciding what I should do. We had a standard loft tank and hot water cylinder heated from both the gas boiler and elec for backup. I installed a pump to get a real shower. Then the boiler packed up. As did the motorised valve, thermostat and timer. I studied unvented but after showering at a friends house I realised the pressure was crap when compared to a pump.

So I installed a combi boiler which gives unlimited hot water to the kitchen, utility, bath and bathroom taps. I plumbed the heating side of things just as if I had a conventional boiler and fitted new stat, valve, etc. I kept the loft tank and DHW cylinder which no only feeds the showers.

Expensive to run? Yes, bloody right BUT it gives me loads of HW and a proper shower so what's a few extra quid for heating!

Reply to
PJO

But the performance of unvented depends on your local pressure and flow rate. There is little point in looking at a friend's system unless they live next door and have an indentical water feed.

I have used pumped, unvented and heat bank systems. Each one provided a fantastic shower at high pressure, and not flow rate limited.

Christian.

Reply to
Christian McArdle

I had that when the thermostat on the hot water tank failed so it stayed on and heated the cold water tank. It was discovered by somebody going for a number 2 and getting a bit more than they expected!

Rob.

Reply to
Rob Nicholson

Agreed but no manufacturer could guarantee me power shower pressure even though I quoted my main pressure so I had to assume that the systems simply could not perform

Reply to
PJO

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