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Does anyone know owt about plumbing?

(19 Posts)
motleymop Sat 08-Mar-14 17:09:50

I am so confused! I don't know anything about plumbing!

I am re-doing my bathroom and intend to have a bath with a fixed head shower and a hand held shower. I will have a thermostatic mixer to 3 outlets (2 showers and bath overflow filler). I will also have a pump.

I am told that one should have a thermostatic mixer with 3/4 inch connections as this gives a better flow rate. But then I have been looking at fixed head showers and they all seem to have 1/2 inch connections. The same companies that do 3/4 inch mixers then have 1/2 inch heads - why is that?

Also, if one has a mixer with 3/4 inch connections, what happens if the pipe from the water cylinder in 1/2 inch? Does the pipework need to be changed, and is that an expensive job?

What's it all about?! I seem to be totally unable to get to the bottom of this story. Any advice would be so gratefully received.

OnePlanOnHouzz Sat 08-Mar-14 23:16:22

I'm not a plumber either !! but I should imagine if you have std plumbing to your bath filler 3/4"pipe ) , and std plumbing to your pump (3/4" ) then use the same plumbing to your thermo valve - and use a reducer, if needed, onto the diverter for fixed head or flexible head. the flow should be good to the shower as it will have been intensified by the pump ?! I don't think you need the pump to feed the bath filler .

PigletJohn Sat 08-Mar-14 23:46:48

You say you have a hot water cylinder. What colour is it?

Is there a cold water tank in the loft? How much higher is it than the shower outlets?

When you press your thumb over the outlet of a hot tap in the bathroom, can you stop the flow? And the cold tap?

motleymop Sun 09-Mar-14 08:10:30

thanks for your messages. I don't have a loft, pigletjohn - the tank is in a cupboard on the landing, and really v little drop in height to bathroom. The tank is yellow. yes, I imagine I could stop the flow by putting my fingers over the taps as there is no pump on the system at the moment.

motleymop Sun 09-Mar-14 08:13:40

piglet - the cold water tank is in the same cupboard on the landing. I was thinking about changing to a combi boiler as those tanks are next to the bedroom and they are v noisy- but now I am worried about the budget. so I thought I'd stick with what I've got for now and put a pump on. but am also worried in future if I decide to go for a combi, the stuff I have installed in the bathroom won't wprk well on the lower pressure system

motleymop Sun 09-Mar-14 08:58:23

piglet - I see on one of your previous posts you mention some good ballcock replacements for noisy cold water tanks. I'd be v grateful if you could point me in right direction.

motleymop Sun 09-Mar-14 09:19:17

fluidmaster brass shank looks ok?!

PigletJohn Sun 09-Mar-14 09:29:18


It is still important to know if you can prevent that cold water flow with your thumb.

How many bathrooms and showers do you have?

Fill a bucket at your kitchen sink cold tap, time it, calculate how many litres per minute it delivers.

Bath taps have to deliver a large amount of water so they can fill a 100litre bath in reasonable time, so they are supplied from 22mm pipes. Showers and basin taps don't need to deliver such a high flow so are fed from 15mm pipes which are half the size (yes they are).

motleymop Sun 09-Mar-14 09:44:57

Thank you. I am not at home right now but will check later. The bathroom water pressure is rubbish for both hot and cold. the cold mains pressure in kitchen sink downstairs is v good.

motleymop Sun 09-Mar-14 10:06:32

ps I have one bathroom only.

worried about combi boiler not giving a great shower though as better pressure with conventional boiler and pump? I'm told that for a really decent shower you need 3 bar?

motleymop Mon 10-Mar-14 22:39:49

11 litres a minute?

PigletJohn Mon 10-Mar-14 23:32:13

If you did decide to go for a combi, 11lpm gives an adequate shower, but would take 8 to 10 minutes to fill a bath.

You say that bathroom cold is low pressure, so comes from the cold tank, which is fine if you are having a pump (you will need dual impeller). Because of the noise, it would be best to have only the shower pumped.

If the cold tank is noisy in filling, get a Fluidmaster valve fitted, it is very quiet, as motleymop says. The brass shank version is sturdier than the plastic. Yours will be side entry, half-inch, as shown.

I do prefer conventional boilers, they are simpler and have less to go wrong. There is no need to change your boiler unless it is irrepairable.

A yellow cylinder is quite old, it would benefit from a red insulating jacket (or two) round it to save energy, and it is helpful to insulate the hot pipes, especially the ones between boiler and cylinder, with climaflex or similar. They will probably be 22mm which is widely available (if very old, could be 28mm which you might have to order.)

motleymop Tue 11-Mar-14 07:37:13

piglet - I can't thank you enough for your advice. I re-tested the water this morning and the flow rate is markedly slower.

I think you are right about conventional boilers being more reliable because people with combis always seem to have trouble with them - and in my last flat the conventional boiler was 28 years old!!

Thank you for your invaluable advice about the red insulating jacket, the climaflex and and the brass shank Fluidmaster. Do you know if there's any difference between Fluidmaster and Fluidmaster Pro?

PigletJohn Tue 11-Mar-14 09:59:59

I don't know what the difference is, if any, though some of the Pro are made of black plastic. It might just be the packaging and pricing.

motleymop Tue 11-Mar-14 19:53:45

can I just trouble you with one more thing, pigletjohn.....

Do you have any opinion re Salamander Home Boost pumps for a combi?

PigletJohn Tue 11-Mar-14 20:11:28

generally, you should not use pumps on a combi or a cold water supply (it is not allowed because it causes suction in the watermain, which can draw in dirt or contaminated water)

there is a concession for certain small pumps of very low throughput.

motleymop Tue 11-Mar-14 20:35:57

The Salamander one says it regulates flow up to the legal limit of 12 litres per minute.

personally I want to keep my conventional but everyone around me is against the idea!!

PigletJohn Tue 11-Mar-14 20:50:06

is "everyone" going to pay for it?

motleymop Tue 11-Mar-14 21:04:35

smile Quite! Also, I would really like a bathroom that functions well - not just ok, at a push.

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