Taking a feed from the cold tank (for shower pump)

[Yarn]

Thanks to some good advice i received on here, I am planning to install a dual feed shower pump. To do this i need to provide a cold feed that comes from the cold tank. This does not exist at the moment. As far as i know, i only have one cold feed leaving the tank that goes to my cylinder. How do you go about taking another feed from the tank? Is there a kit i can get so that i can just drill a hole in the plastic. I notice most new cold tanks don't come with multiple fittings.

Thanks as usual.

 

[Andygasman2010]

Drain the tank off and fit this:

http://www.screwfix.com/app/sfd/cat/products.jsp?id=14952&ts=76512

(this is JG push fit but others are available, like compression)

I drill the tank with a cone cutter bit but some guys just heat up a bit off 22mm copper and melt it through.

What are you doing about the hot feed for the shower pump?

 

[Yarn]

Thanks Andy, I hoped it would be that simple! I think i have an old redundant run back to the bathroom to run the new 22mm cold pipe, so shouldn't be that difficult.

I still may replace the tank if it is not big enough to support a long shower. What size do i need ideally?

The hot already goes to the bathroom from the tank, but now i think about it there is a tee off this pipe for the kitchen sink (before bathroom). Its quite likely that the kitchen taps will be used at the same time as the shower. is this going to be a problem?

I was going to fit the pump after bathroom tap, but before bath tap and shower tap. This would be end of the pipe run.

Cheers.

 

[Yarn]

Re-reading the wickes leaflet i now see that the surrey flange solves this hot water problem and if im creative i can reuse most of the pipe run.

 

[Andygasman2010]

You can't use that existing hot pipe to the bathroom, the shower pump will need it's own hot feed from the cylinder. I've seen some feeds taken off the cylinder draw-off but it's best to use a surry or essex flange.

The size of your tank is dependant on your usage but a standard 50 gallon tank is fine for an average 3 bed semi etc...

Obviously increasing the size of your cold water header tank will not increase the volume of HOT water, you'd have to upgrade the cylinder to do that. I'd fit the pump as we've discussed and then try it. You can always upgrade the tank/cylinder later if required but i doubt you'll need to unless you have 3 or more people having showers one after the other.

 

[Yarn]

I am having trouble finding a suitable pump. I wanted a twin impellor that could pump for the bath aswell as the shower. About 1.5 bar, nothing to over the top. Can anyone recommend one thats good for the money?

 

[Richard C]

As with anything in life, you generally get what you pay for & with pumps, I would avoid the cheaper DIY units. Stuart Turner Monsoon or a slightly cheaper Salamander but you must use RHP pump if you want to power the bath &/or other taps as well. Weather or not this will cause problems if used at the same time as the shower will largely depend on the size of the delivery pipe work involved, it’s design & selecting the right pump capacity; a 1.5 bar pump is pretty miserly choice to run a whole house (feeding other taps) system. I would not advise trying to use the existing run & your likely to get problems with pressure fluctuation if you fit the pump after other tee’s; much better to run a separate, dedicated shower supply. Fit the pump as close to the water storage tanks as you can, ideally at the base of the HWS tank & use 22mm feeds to the pump. Fit the cold water tank feed at the opposite end to the water inlet valve to minimise risk of the pump drawing aerated water. Be careful if you plan up & over loops to the shower head, go any closer than 600mm to the bottom of the CWS tank & you could be in a potentially negative head situation requiring a more expensive NH pump; vents also required at the tops of the loops.

 

[Yarn]

Thanks Richard,

That is a helpful answer. I shall just clear up a few points, if it helps anyone else:

Firstly, My bathroom is on the ground floor. My tank is on the first floor.
The mains water pressure is very low, so I wanted to use the pump to fill up the bath as well as the shower. This is the same bath tub that the shower is located in! so very unlikley that they will both run at once. I do not plan to use the pump for anything else, so in this case it will be one or the other. 1.5 bar is probably enough for me, but i take your point.

I mentioned re-using the pipe run, what i meant was, just reusing the copper in its current location, but changing the connections at the tank end so that it is a unique pipe for the pump. in effect i will add new pipe for the things that are not on the pump (kitchen tap and basin tap only). I will also use a Surrey valve on the tank.

I think the main thing i wanted to hear was that i did need a RHP pump if going to bath aswell.

Some useful advice about the pipe work too, thanks.

Cheers, guys, you really have been helpful.

 

[Richard C]

As long as you use dedicated feeds to the pump & for the bath/shower supplies you should be OK with 1.5 Bar as long as you don’t pick a high pressure drencher head. If using a Sally, you will need the RHP pump but fit 22mm from the tanks to the pump even if you subsequently drop to 15mm after the pump; I prefer to fit 22mm right up to the shower mixer. If the existing bath supplies are run in 22mm, you could use those & modify accordingly but check they aren’t restricted by crud; if in doubt replace them. Essex flange is best IMO but as long as you use an anti-aeration flange it’ll be OK. Any isolation valves should be full flow (gas lever type) to avoid restrictions, change any that aren’t.

 

[TicklyT]

If possible, fit the new outlet to the CWST below the level of the outlet feeding the hot cylinder. Done that way, if the CWST should run dry for any reason, the hot feed will fail first, so your shower turns cold instead of scalding you.