DIY Doctor

Loads of shower questions

Postby TommyT » Sun Feb 03, 2008 2:25 pm

I have been trawiling posts on this forum for ages, but getting more and more confused.

I live in a flat that appears to have a fairly modern mains fed combination bolier, and i am looking to redo the bathroom.

the current shower has pathetic pressure, it is electric so my understanding of this is that the water is heated by an element that the water is passed through, hence the reduced pressure?

also when the toilet is flushed the low pressure light comes on and the water goes cold for about 2 minutes, is this normal or something wrong?

so what can i do to improve the shower pressure, if anything? would a "better" electric shower heat the water more quickly thus providing increased pressure, or is it a case of installing a different type of shower altogether? would a steam shower (the all in one type showers) be suitable in my situation, or just result in rubbish pressure and be a waste of money?

I also like the look of the tower type showers that fit in to a walk in shower, or into the corner of the room, but would this just result in the same situation as my current shower?

i would basically just like to know what would be the best shower i could get for my situation, and what wouldnt be suitable, i am willing to spend decent money to get a decent shower experience, i just dont want to waste money on something that will be no different

thanks in Advance
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Simply Build It

Postby bobplum » Sun Feb 03, 2008 8:27 pm

firstly are you sure its a combi what kw is the shower and how old
you say when the toilet is flushed the low pressure light comes on im assuming thats the light on the shower,to me it sounds like poor mains pressure or its not a combi,do you have a cold water tank in the loft or a hot water cylinder in the flat
if it is a combi id ask the water authorities to check your water pressure
also check the pressure gauge on the combi should read approx 1.0 bar
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Postby simpleton » Sun Feb 03, 2008 8:35 pm

Hello mate. If you have a combi boiler then in theory you should have mains hot and cold water. Is the shower head blocked up with limescale? Also its perfectly normal for the low pressure light to come on when you flush the toilet cos the toilet will be taking the water to refill the cistern, so no problems there. You cant fit a pump if youve got a combi cos you cannot pump mains pressure water. Unless you do have a cold water tank somewhere in which case you can fit a pump. I would be inclined to take the shower head off and check for limescale build up and also have a look in the shower unit for the same
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Postby Paulo83 » Sun Feb 03, 2008 9:34 pm

Put in either a mixer shower or a thermostatic. Check that your combi boiler will work with these types of shower. If you fit a better electric shower its more than likely the electric cable will need redone with a bigger one.

I just put a mixer shower in off my combi boiler-works great and easy to install, just need to run a hot pipe up beside where the cold one is at the moment for the electric shower.
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Postby chris_on_tour2002 » Sun Feb 03, 2008 10:56 pm

it is normal in this case for the shower to lose pressure when you flush the toilet - electric showers are mains fed (or should be) and in your case so is the toilet. the pipe feeding the shower also feeds the toilet and in fact the toilet is ahead of the shower in the line (ie further up the pipe and closer to the incoming main) so the toilet will starve the shower of water until the cistern has refilled and the demand from the toilet is no longer there.

the low pressure indicator on the shower is a safety device for exactly these eventualities. a drop in pressure and flow through the shower could result in scalding. the electric element in the shower will shut itself off when it senses a drop in the feed and stop heating the water until the pressure and required flow rate return. so nothing wrong with your system, on the contrary the safety cutout is doing exactly what it's designed to do.

with regard to shower pressure thats mostly down to the power of your electric shower. they go up to 10.8 kilowatts, these are the most powerful and offer the best flow rate. check yours, it may be lower. also check if there are any isolator valves on the shower if so are they fully open? check for blockages where the main enters the shower - may need to remove the shower from the wall to do this, get help if you are not sure what you are doing, they take a heck of a lot of juice from your electricity main and can give a very nasty zap.

if you have a gas-fired combi then you can change your shower for one that runs from that. you need to get a shower that is compatible for use on a combi system (no power showers unfortunately) but there are many out there that give good pressure, i am about to install one in my house.

this should give better pressure than you are currently getting. seek advice from your bathroom store or plumbers merchant when purchasing your new shower, they will advise the best configuration for your particular system.

with regard to steam/tower showers, not entirely sure what you mean by tower showers but i think you are talking about the ones with the jet spray nozzles. i fitted one of these, you need to have good pressure for these to work properly (3 bar for most of them). usually you run these from a pump and for that you need hot and cold storage tanks, no good from a combi, but again check with you local merchant.
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Postby chris_on_tour2002 » Sun Feb 03, 2008 10:59 pm

one further thought, check to see if your current shower has a summer/winter setting, if so make sure that it is set to winter.
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Postby TommyT » Mon Feb 04, 2008 9:15 pm

Thank you all for your very helpfull replies,

some extra info based on peoples questions, i live in a flat and there are definatley no tanks anywere, i am certain it is a gas fired combination boiler, it appears to have been installed very recently, its a modern looking fer one. (only moved in 3 months ago).

the pressure guage shows just over 1 bar on the boioler, the shower says 9.5kw, there is no winter summer setting that i can see.

so sounds like a mixer, or thermostatic shower are the way to go then, it appears that they seem fairly easy to install (as in not much to them) which is a bonus
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Postby markflip » Thu Feb 07, 2008 3:36 pm

If the cold water pressure is low (as it sounds) it may be that a thermostatic shower may well be better as it uses both hot and cold water supplies BUT - before you go to the expense and trouble of fitting a thermostatic shower, you could consider the following to give you some idea what the flow rate would be like: purchase one of the plastic shower attachments with rubber couplings that fit over the taps (couple of quid) turn the hot on full bore then increase the cold until it is a showering temperature (this assumes that the hot supply is the limiting factor, which it usually is - if it won't cool down enough turn cold on full and increase hot until it's warm enough). If it's still only dribbling I'm afraid you're stuck without installing pumps and tanks.
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