Pumped shower.

[Matthew]

Well after a lot of thought I am back to square one, certainly from a cost perspective anyway. Fitting an unvented cylinder was getting rather expensive so I have been having a look again at shower pumps.

Has anybody recommendations on types or manufacturers. I need to be able to drive two showers using the balanced flow from our header tank. The hot and cold 22mm feeds to the showers run parallel in our loft to the downpipes. I would imagine removing a section of pipe and plumbing in a pump would be quite straightforward. I would have to build a small platform to straddle the ceiling beams and was thinking of placing maybe a patio slab up there for noise prevention. How difficult are pumps to fit and how noisy are they?

Thanks, Matthew

[David Hansen]

On 3 Oct 2006 02:34:53 -0700 someone who may be "Matthew" wrote this:-

I'm not sure that many are designed for more than one shower and it may be better to use two separate pumps. Either way both showers should be thermostatic. Alternatively two venturi showers.

If the two pumped showers are to run at the same time you will need to look at the amount of hot water storage. One does tend to exhaust a fair proportion of typical hot water cylinders. You may also need to look at the size of the cold water storage.

Typically they have pushfit connections on the end of flexible tubes. You will also need a spur from the ring main. In the loft they will need to be insulated, but they also need to be able to get ventilation air and dissipate heat.

They are noticeable, but not noisy.

[Andy Hall]

If you buy a good quality one they are very good and quite quiet.

I would suggest looking at Stuart Turner's larger products for this - very solidly engineered and a full range of spares available. If you are within reasonable distance of Henley on Thames then they are well worth a visit. You can then buy from plumber's merchants looking for the best price.

[Christian McArdle]

Fit a Stuart Turner Monsoon 2 or 3 bar twin. The positive version is cheaper, but you may find you need to buy a negative version if a shower head is near the tank level (i.e. cold tank on loft floor, shower head just below the ceiling).

Easy, if you don't mind a bit of plumbing.

They can be a bit noisy, although the patio slab may well help. Place a rubber mat between the slab and the pump and between the slab and the platform.

Christian.

[Matthew]

I have been looking at the price of Stewart Turner pumps and they seem to be the Rolls-Royce of pumps. Quite expensive. To feed

2 showers what sort of presure rating would I need, 1,2,3 bar etc. I noticed that screwfix and toolstation sell a cheaper variant of shower pump called the salamander, any good. Of course Wickes do their own make etc Can you recommend any good suppliers?

I have two parallel balanced 22m copper feeds leading to the shower through the loft. As I mentioned earlier I was thinking of placing a paving slab acorss 2 roof joists and putting the pump on it. I was going to cut the two sections of exisiting pipe out and plumb in the new pump by installing 4 new short upright sections of 22mm copper pipe using speedfit elbows onto the exisiting pipework. The flexi hose from the pump would then connect to this. Do you think this is suitable? Hopefully a days work.

We are also currently thinking of buying a larger 140litre horizontal copper cylinder and moving that to the loft.... but thats for another day. Would there be any issues related to the pump if we did this.

Thanks for any advice, Matthew

[Andy Hall]

Yes they are. However, they are a Rolls Royce product with service and spares that one would expect. Actually, the spares are very inexpensive. I recently needed to replace the control relay box on mine and the price was £7. I think that the important issue is maintainability and cost of ownership over time. If you buy the cheap products, you may not get spares and you certainly won't get the lifetime out of them. Been there and done that. If you calculate for a 15 year period you will have bought 2 possibly 3 cheap pumps, so it isn't worth it unless you only expect to stay in the place a short time. You would need 3bar for two showers.

No because there aren't any. These are a false economy.

That sounds reasonable.

The issue is the head of water of the supply tank. Some pumps have a minimum for that relative to the pump.

[Matthew]

This may be a silly question....

If we have a hot water tank of say 140litres then using a 2 bar shower pump then how long will it take for the tank to be exhausted with one or two showers hanging from the system?

Thanks, Matthew

[Christian McArdle]

The pressure is irrelevent. The calculation depends on several things.

1. The capacity of the cylinder (140 litres)
2. The power of any heating system used to reheat the cylinder.
3. The flow rates of the showers used (this might vary even according to the handset setting)
4. The temperature of the shower.

Less importantly, there will be effects from

1. The temperature of the incoming water main.
2. The temperature of the loft
3. The size of the cold water cistern.

If we assume some following numbers:

140 litre cylinder with rapid recovery coil 28kW boiler turned on with hot water priority. 10 lpm showers 40C temperature 5C coming from the loft tank

This will last about 14 minutes.

Christian.

[marvelus]

You didnt mention the temperature he kept the cylinder at ;)

Did you do all the physics and calculus? I no longer can but have a gut feeling its somewhere between 21 and 28 minutes.