Shower pump, whole bathroom?

[Simon Avery]

Hello All

Refitting bathroom soonish, in early planning stages now.

Entire hot water to bathroom supplied from ground floor (it's a bungalow) indirect HW tank via 22mm copper. I want a thermostatic shower with a decent flow, a bath that doesn't take a week to fill and a WC & Washbasin.

I need a shower pump for the shower, otherwise it just won't work - the showerhead being higher than the HW tank (although CW feeder above HW tank is a couple of feet higher, so may get a dribble - but not enough to have a decent shower).

Question: Can I just put the shower pump on the incoming 22mm HW feed to the entire bathroom, or is that a bad idea to have it triggering for washbasin and bath and it should just go on the Shower feed?

BTW - CW - unsure if going to put mains or use a feed off the CW tank in loft. Mains pressure ain't great, so prolly better to run a 22mm down and avoid washing-machine induced scalds? It's on mains atm, but I'm worried that a thermostatic shower will need more CW flow than it can supply. (Weedy 15mm mains, so not only crap pressure, crap flow also)

Am I right in thinking that as it's unlikely more than one thing is going to be using CW at any 1 time in the bathroom then a single feed, with bits taken off it when needed won't have a big impact on flow, or do lots of joints and corners seriously slow things up?

Recommendations for a reliable and reasonably powerful shower pump? (Not done one before)

[Grunff]

Hi Simon.

Something to bear in mind. The pump has flow switches to detect flow and switch on. In order to get enough water through these to tuen on the pump you will need some head. I think mine recommended a minimum head of 40cm.

I was tempted to do this, because we're on a private supply and our 'mains' is only about 1bar. But I decided against it because of the noise - pumps aren't quiet, and while I'm happy to live with the noise while showeing, I wouldn't want it on every time I open a tap.

I suppose the only scenario when this might be a problem is if you flush the loo then turn on the shower - you'll have low flow until the loo has finished filling up. We have this situation with the loo + basin, because that's not pumped.

Stuart Granger seems to be the one recommended by everyone in the know. Ours isn't, it's a 'NewTeam Varispeed' from City Plumbing. It's two years old, and has given pretty good service every day for the last 2 years.

[Roger Mills]

basin as well as the shower. Most shower pumps are double ended - with hot one end and cold the other. In any event, you should take the cold feed from the header tank rather than the mains - because the shower mixer will work best when the hot and cold water pressures are more or less equal.

Many shower pumps have a flow switch which switches on the motor when flow is detected. This, of course, relies on getting *some* flow by gravity when you open a tap or turn on the shower. As long as the water level in the header tank is a reasonable height above the shower, this should be ok. [The height of the hot water cylinder is not relevant, because the flow is being driven by the pressure from the header tank].

Hopefully, others will advise on specific shower pumps. I bought mine many years ago as part of a kit with the shower mixer etc. Didn't think of using it for the bath and basin though!

A final thought - if you use the cold tap on the basin for drinking (e.g. filling a Teasmade) you may prefer to keep the mains feed to this rather than getting it via the header tank.

Roger

[Andy Hall]

Given the situation, I would look at a chunky Stuart Turner like a Monsoon 3 bar twin and run a 22mm cold service from the CW tank to it.

Is the shower going over the bath? If so, you could get an all singing all dancing thermostatic mixer to do both. If they are separate, then a thermostatic mixer for each or a thermostatic mixer for shower and simple mixer for bath. You could even have separate bath taps for that matter.

I wouldn't bother including the basin in the equation.

If possible, try to mount the pump low - e.g. floor of airing cupboard, although it's generally not super critical.

If you can put in a Surrey flange to the top of the HW cylinder, it's a good plan, then the bathroom will be completely independent of anything happening in the rest of the house.

.andy

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[Grunff]

Or even Stuart Turner...

[Simon Avery]

Hello Andy

k, That's two votes for that one then. I didn't know about the twin. I don't think I need the CW pumped though.

No, different. Wifey likes showers, I like baths - so I get a nice deep bath that's long enough so my knees don't get cold but only if she gets a nice shower...

There's only one place a shower can realistically go, and that's in a recess which is exactly 1200mm wide by 900mm deep. (Existing block walls) Somewhat relieved to learn that stock trays of exactly that size are available. :)

Nah, that's a non-luxury feature. Shower and bath are more important.

Can do, there's a nice section of run in the underfloor void that's perfect, or will be when I get power to it.

Hmm, googling...

[Simon Avery]

Hello Grunff

Ah - I hadn't considered that, good warning! Not a problem though - the HW tank is ~80cms above the floor and the pipe run is ~30cms below that, so I think I'll fit the pump down there.

Another very good point and one I hadn't considered. Flow with current arrangement to bath is adequate, so I'm inclined not to bother then - just pump the shower section.

[Andy Hall]

If you are going to run both (in effect) from the CW tank since it supplies the HW cylinder, then a twin pump is really the right way to do it because the flows will be better balanced. If the cold is derived from the mains, it could be all over the place. OK, the thermostatic valve will help with maintaining the temperature, but the overall flow will vary. Having the whole thing separated from the mains, pumping both, will give a good and balanced result.

I think that you could reasonably connect both the shower and the bath to the pump so that you will the bath more quickly. It didn't seem worth running up the pump for the basin.

That's a bit of luck. They are normally 1cm too large for the space.

I'd be a little careful with that. The void under a floor can get pretty cold so that one should consider insulation to avoid heatloss and potential freezing. OTOH, the motor of the pump will generate heat in operation and that needs to be allowed to escape.

There's a variety here.

flanges are said to be a bit better because the fitting is totally separate. However, they need more courage to fit to the cylinder.

.andy

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[OldScrawn]

Think about what will happen if the pump leaks. I've had two seal failures, one after a couple of years, one after 3 months, and between these have twice had screw connectors shake themselves loose. These used to soak the cardboard boxes of stuff in the loft before dribbling down and staining ceilings. My pump now sits in a small cold water header tank, with a drain connected to the normal header overflow.

[Capitol]

Pump leakage is a valid point, in >10 years, I've only had a few minor weeps, but my pump is visible and sits in a small tray for this reason. Our new 3 bar pump is a Watermill, brass construction, lower cost than a ST. source kbb2000) My experience has been that getting sufficient water flow (10-20L/m) can be a problem even over short distances. Using 28mm piping as much as possible and both Essex and Suffolk flanges in parallel from the HW tank has been the best IME. The pump needs to be as close to the tank as reasonably possible. This approach supplies pumped H & C water to the whole house. IME pumps are noisy devices and best used only when necessary. If the pump is enabled by a one operation timed switching device, then it is only used as and when necessary and turns itself off. Over long distances( say

100'), the hot water wastage is very excessive unless 15mm piping is used or the water is circulated around a lagged loop( increases effective HW tank capacity). BTW, I investigated the local water supply flow rate and found a variation between 5-10L/m according to the time of day! Worst at around 6pm Regards Capitol

[Christian McArdle]

The height of the HW tank is totally irrelevent. The only influences are the height of the water level in the header tank and the bore and effective length of the pipework. (Effective length includes penalties for elbows and tees).

It is very useful to have the pump for the bath tap. You are right not to want it on the basin, though. Can you replumb the basin to before the pump?

This is another reason to install bath pumping. On mine, I found the low head coupled with the double check valves made starting the pump on shower to be unreliable. However, it was easy to nudge it by blipping the bath tap, without needing an ugly and expensive "negative head" upgrade for the pump, which usually consists of yet another decaying green tangle cord from the ceiling.

I had a system just like you are considering, with mains cold and a single impellor on the hot side for bath and shower only. However, you might want the separate cold feed if your mains are that bad and use a twin impellor pump. You may need to seriously increase the size of your cold water header tank to ensure you don't run out.

One feed will be fine. If pumped, 15mm won't be too much of a disaster and will even get hot water quicker. I suggest buying a proper pipe bender. Avoid elbows unless absolutely necessary. Flowed bends are cheaper (if you've already got the tool), allow greater freedom in choice of angles, drop much less pressure, allow more flow and are less noisy and prone to hammer.

Everyone recommends Stuart Turner. However, I had a Showerforce single impellor for 99 quid on the hardest water imaginable. No problems, even after two years.

Christian.

[Christian McArdle]

You may find this is because the hot water cylinder has poor connection with the header tank. Ensure the feed to the header tank is at least 22mm and has only flowed bends over a short distance and no bore reducing valves. If this is done, you might not even need a flange at all, let alone two.

Christian.

[Capitol]

It is plumbed in 28mm, with a run of 10' and a head of 8'. The problem is to get hot water out of the tank at a sufficient speed. I haven't seen 28mm Surrey flanges as a readily available item, have you? Regards Capitol

[Christian McArdle]

What sort of speed do you need? I had 22mm to the bottom of the tank and then no flange, just a run of 22mm to the pump from the top fitting. It filled a bath in not much over a minute. Are you sure it isn't just a slow pump? What sort of flow rate do you get? Do you get air in the water/pump?

Christian.