John P
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| posted on 19/2/15 at 10:49 PM |
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Running two showers at the same time. Advice please.
I've just created a new en-suite with a thermostatic shower running off the combi-boiler which has a maximum output of 31 kW. The results are
fine and we can have a very good shower with plenty of flow although if we turn a tap on elsewhere you can notice a reduction in flow rate.
Concern is I would like to have a similar shower in the main bathroom which could be used at the same time so when we have visitors we don’t have to
avoid running both showers simultaneously.
Is this going to be a problem?
I did think about using a low water supply pressure electric shower connected to a small new cold tank which I could install over the bathroom
ceiling. However these are quite expensive and although heating would be taken away from the combi and the flow would presumably be OK as soon as
the water level in the new cold tank started to fall the ball valve would open and presumably pressure to the combi would drop thus adversely
affecting the en-suite shower.
Any suggestions?
John.
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Chris_Xtreme
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| posted on 19/2/15 at 11:35 PM |
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have the same issue in our house.
big combi boiler in loft.
shower in loft, great until a tap or anything gets turned on downstairs. Easier for the water to go somewhere else, shower turns into a trickle.
this is on different floors so you may not have the same problem.
also out water pressure is less than 3bar, so make a big difference.
I have been looking into cold water accumilators
not specifically this one but:
http://www.gah.co.uk/heating/coldstream/technical-specification.php
with these if you do use it all up, you just drop back to mains pressure.
or the other option is to have a cold water tank fed from the mains, and then pump the whole house with a variable pump. problem solved - as long as
the tank is big enough and doesn't run out.
something like:
http://www.pumpexpress.co.uk/acatalog/4cr80_sirio_pump_controller_potable_vessel.html
both solutions mega bucks, when we did the loft conversion I wish I knew more and could have built something in..
for me the biggest problem is where to put the tank!
[Edited on 19/2/15 by Chris_Xtreme]
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trextr7monkey
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| posted on 20/2/15 at 01:42 AM |
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We have installed 2 electric power showers in adjacent rooms each with own cold feed and pump
Works wonderfully we didn't want any pressure fluctuations as they are inevitably used simultaneously while others are making breakfast. We
looked at all sorts but the bloke installing them said it was best solution
http://www.flickr.com/photos/14016102@N00/ (cut and paste this dodgey link)
Our most recent pics are here:
http://s129.photobucket.com/albums/p211/trextr7monkey/
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loggyboy
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| posted on 20/2/15 at 06:51 AM |
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Its a common problem with developers as combis are favoured due to space and economics. However there are combis on the market that can cope with
higher demands, most usually have a small tank built in to them to provide a small backup when demand is high. Check the Alpha Flowsmarts.
Without replacing the entire system your options are limited to using a mains driven electric or staging the use of showerscand taps.
[Edited on 20-2-15 by loggyboy]
Mistral Motorsport
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Irony
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| posted on 20/2/15 at 09:51 AM |
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Your taking all the fun out of showering. I use the tap trick to get people out of the shower faster in the morning. Everyone in our house knows
what you mean with the shout 'hurry up or else!!!'
Best way is to slowly turn the tap on so they don't realise then slam the tap off quick and the extra pressure turns the shower ice cold!!!
[Edited on 20/2/15 by Irony]
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dhutch
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| posted on 20/2/15 at 12:41 PM |
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I have a Main HE30 which sounds similar and think its working flat out to produce shower water.
Works find normally with thermostatic bathshower mixer, drop in flow if you open another cold tap, total reduction to a dribble if you open the
kitchen hot tap, but also at night when the pressure is a bit higher (1am say) you have to throtal the flow at the mixer slightly to get it upto peak
temperature.
Its a high flow shower at about 25l/min and I am sure you could get an eco head or one with various modes, that would use less.
Systems on narrowboats are using about 8kW instant gas heaters on about 10l/min, and they work find, if more like a weak electric shower.
How does the water come into your house?
- My house its 15m copper coming out of the floor, end off, old ex-council build.
- Parents however they have 25mm plastic out the floor, isolator steps down to 15mm copper.
Not what I would do for an every day shower, but if its infrequent use I would put in an unpumped electric unit without issue.
If you have a feed like at my parents, I would 'T' in to it before the step down, either at the point of entry, or by extending in 22mm
into the house.
NB; I am an engineer with hydraulic experience, but not an experienced plumber.
Daniel
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snapper
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| posted on 20/2/15 at 01:13 PM |
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Big issue for me is the 15mm water feed from the main.
I have a combi, feeding the old house and new extension thermostatic shower
An electrical 10.8Kw in the family bathroom and a hot tank for the ensuite bath, basin & bidet
Turn a tap on and the showers go slow
I'm working on a solution but it always comes back to a bigger main feed pipe
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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dhutch
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| posted on 20/2/15 at 01:27 PM |
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quote:
Originally posted by snapper
I'm working on a solution but it always comes back to a bigger main feed pipe
Whole house booster pump...
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John P
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| posted on 20/2/15 at 03:48 PM |
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I've been thinking about this a bit more and wonder if I could install a small cold tank to supply an electric shower but then I would need some
way of not allowing this to start to fill until the level dropped significantly. That way you could have a full shower from the water stored in the
tank without it staring to re-fill and taking away flow / pressure from the en-suite thermostatic shower.
Perhaps a motorised valve in series with the ball valve and a lower level sensor to open this motorised valve once the tank is nearing empty.
What do you think? Is this feasible?
John.
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ed1801
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| posted on 20/2/15 at 03:56 PM |
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Could you have two ball valve at different heights, the top one only dribbles so doesn't affect the rest of the system, but the bottom one at
full flow so it never empties?
You need like a giant accusump - do they do them with a 200 litre capacity? 
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geoff shep
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| posted on 20/2/15 at 10:25 PM |
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We have a similar setup with a combi/mixer thermostatic as the main shower and an mains cold feed electric shower as the secondary one. We
don't have a problem with them both running together although they are both drawing on the overall cold water supply.
The only really noticeable change to the the mixer shower comes from someone else turning on a HOT tap elsewhere as this then swamps the ability of
the combi boiler to produce enough hot water. It doesn't get overly affected by a cold tap going on.
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BenB
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| posted on 20/2/15 at 10:33 PM |
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Pressure equalising valves. Respond far quicker than a thermostatic wax capsule and in my experience never go wrong.
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