Water pump installation...general questions

[neil7744]

Hello,

New to the forum!

Just bought my first house! (well bungalow)!

Anyway to cut a long story short in all of our rented accomodation prior to buying, the showers have been rubbish. First place we didnt even have a shower, second was a mains fed 6kw electric (flow rate a trickle in winter) and now a 9.5Kw (and thats only really any good during summer months)..and only any good when no one flushed the toilet or had the water on downstairs otherwise you got scalded!

Anyway we now have a gravity fed mixer shower! I want to install a pump. Tonight i was doing some basic 'investigation' into where everything is plumbed. It looks straight forward and easy enough to install, but just have a couple of questions...

1) the hot water tank outlet pipe and cold feed are next to each other in the airing cupboard running alongside the wall. Whats the best way to get a nice clean cut on these? I dont think there is enough access for tube cutters!

2) supplying power to the pump...how are these typically fed? does it need its own feed direct from consumer unit or via a fused switch off the sockets?

3) more than likely i shall be increasing pressure to all the hot feeds in the bungalow and also a few cold (ie the shower & bathroom sink). My plumbing is chased into the walls and running under the floor using a mixture of brazed and compression fittings. Will the existing 1970's plumbing be capable of handling a higher pressure?

Im fairly confident with electrical work and do a fair bit of plumbing at work, so will certainly give it a go!

Any help would be appreciated.

 

[flameport]

To cut the pipes use one of these or similar: http://www.tools4trade.com/d-7023048-22mm-pipetube-cutter-c0265.aspx
and if there really isn't enough room for that, you will either have to remove the pipe from the wall and hope there is enough to move the pipe out slightly, or hack a hole in the wall to accommodate the cutter, or cut the pipe where there is room and then join/replace as required.

Pumps are typically powered from a 3A fused spur.
The old plumbing will probably be fine, but there is only one way to find out.
If you use the existing hot feed (which presumably is from the top of the cylinder), the pump may draw air in via the vent pipe, or air may collect there and enter the pump causing damage. Or it may work just fine. The proper way is to take the supply for the pump from a separate connection on the side of the cylinder.

If you insist on using the pump for all of the outlets, note that this will cause the pump noise every time a tap is turned on - probably not what you want in the middle of the night when someone uses the bathroom.

What size is the cold water storage in the loft? - it needs to be large enough to avoid it being emptied when the pump is in use.

 

[neil7744]

ok...did a bit more reading last night regarding wiring...so im fairly confident how to wire the pump.

i was going to use a surrey flange on the top of the hot water tank to eliminate air.

as for the cold water tank size...this is what i need to do tonight to measure the size to work out a realistic sized pump. Mind you i want pressure and flowrate, however would like to be able to shower for longer than 4 minutes lol!

anyone know how i can work out mathmatically what my best option would be. I can easily find out botht he hot and cold water tank volumes to get an idea, but also surely i need to take into account mains feed filling th cold water tank as the water level is used when having a shower?

 

[Hugh Jaleak]

Dont count refilling of the tank in your calcs. The hot water tank is replenished from the cold storage cistern (tank) so basically all the water will be taken either directly or indirectly from the cold cistern when using the shower. Highly doubtful even a good mains supply will be able to keep up with the flow rate of a shower pump.

Longer shower needs a bigger tank

 

[neil7744]

yeah i see what you mean.

should be ok. bought all the gear the other night. went for a 2 bar as i works out better. started plumbing it tonight. hopefully if things go well and ive done it right, it should be working very soon!