Increasing Hot Water Pressure

A question about : Increasing Hot Water Pressure

We've just moved into a new house in Edinburgh and we have really low hot water pressure in the bathroom and the shower room. Seems in the Kitchen the hot water pressure isnt too bad, nor do our neighbours indicate to us it may be a supply issue

As such im wondering if its a good idea to install a pump and what sort to go for. I understand the Stuart Turner Monsoon pumps come well recommended but im after some advice on which type to use

Clearly we want a pump that isnt specific to one device (i.e. a shower or a bath) but rather to all the applicances in the house. Im thinking a Stuart Turner Monsoon 2 bar single ended positive pump might be the one but would appreciate some help and also where best to install it (straight off the boiler?)

Best answers:

• I assume you have a hot water tank and not a combi boiler?
  I have this problem - with a tank system - and consulted a plumber. He advised that the simplest way, if physically possible, was to raise the cold water header water tank. Even a couple of feet will apparently have quite an effect.
  I did look at a pump, but have been advised that noise and vibration are almost impossible to supress. Judging by some houses I have seen with power showers, that might well be true.
  With a combi boiler, none I have seen have the capacity to heat water fast enough!!
• Yeah, its a combi boiler ... quite an old one too ..hence why Im wondering whether the pump will help
• The limitation on most(all?) combi boilers is they simply cannot heat enough water quick enough at even normal flow, especially when the input water is cold.
  If you look at the spec sheets even for large modern combi boilers they will quote a specific flow rate when heating the water by 35C. So adding a pump I suspect will increase the flow of tepid water.
  A BG heating heating told me that in the winter the commonest cause of call-outs were to Combis that just won't heat up enough water.
• Hello
  I'm new so forgive me if this has been answered elsewhere.
  I work for a Water Company, and am often asked about issues with pressure and supplies.
  It could quite simply be that the combi you have is not sufficient for the needs, like having a 1.2cc engine in a luton van, loading it up and expect it to lug around the load with ease when really a bigger diesel engine will do the job with ease but will need to for fork out more.
  Also if you don't have good pressure to start with, generally if you are on a common / shared supply it is not the best design and a traditional system may be better.
  I have a combi that is over 10 years old in a 3 bed semi and I can shower from that upstairs with ease and the pressure to my house is adaquate (for someone who works in the industry) I also had one in a previous house and that worked fine but was told to have a single supply to the house before one could be installed.
  The key will be down to the design and a good plumber, which can be hard to find if one is not recommended.
  Also if you go to BG, they (or there contractors) have frame work agreements with manufacturers and will only supply them unless requested.
  Hope this is of help
  Loki
• Hello all, firstly thanks in advance.
  I have just moved into a new house which is about 9 years old.
  It has a normal boiler with tank which is a Potterton 50F.
  Their are 3 bedrooms, a kitchen 2 bathrooms and a lounge.
  My problem at the moment is hot water.
  In the bathroom we just about manage a trikle of hot water from the shower, barely sufficient to wash you. In the kitchen the pressure is a bit higher, but still low.
  After a centeral heating engineer came out for a seperate issue, he suggested their was a cold water feed pipe to the water tank which was at the wrong angle, I got that changed but with no affect.
  I initially considered installing a Electric shower, but am reconsidering seen as the pressure to thekitchen will still be low.
  I have considered a combi boiler, but at an estimated Ј1800 it wont be something i can invest in for a few years.
  Does anyone have any suggestions?
  Me
• We had this problem and I wanted to get rid of the electric shower as having to growing boys they just stood under it for 20mins at a time. When we change the bathroom around my first job was to raise the tank by about a mtr it has given us a lttle more head of water that has made all the differance. In the summer the pressure is possibly not as great as the mains electric but in the winter it is good as you can have the water as hot as you want without loss of pressure. My advice is if at all possible raise the tank. I would say there is a about 1 1/2 mtres frm the bottom of the tank to the shower head. I asume if you have a bigger tank header tank the pressure will be greater?
• As Cardew says, the problem is that combi boilers are basically rubbish and won't deliver sufficient flow of hot water in many cases. Obviously they are even worse in the winter when the supply temperature is colder.
  CrazeUK - your problem certainly won't get better by getting a combi boiler. What you need is to sort out the flow into your cold water tank, as your first engineer said. I'm not sure I believe that the angle of the pipe is the issue - but it certainly sounds like the problem is somewhere between the main water feed into the house and the cold water tank.
  John 3:16 - I don't think that the size of the header tank is relevant. Pressure is proportionate to height, not to size of tank. But raising the tank as you did is probably worthwhile in some circumstances.
• When I said bigger I asume this would also take into account the height.
  Here is a question for you.
  If you had a header tank 6inch square 1mtr high would it have the same pressure as a tank 3mter square with water 1mtr high?
  I just wonder if volume came into it?
  We also made sure that we had 22mm pipe to the shower so flow was not reduced
• Yes.
  Pressure = h ρ g where h = height ρ = density and g = gravity.
  The size of the container doesn't make any difference.
  But a header tank as small as you suggest would be likely to run out of water and then you'd have no pressure at all!
• Are we missing a trick here. We should manufacture long thin header tanks. You will get them in the loft easy and the pressure will be better. The mains pressure should always be up to filling it up!
• Strange this thread has been resurrected. As I said in post #2 I have this problem in one bathroom - our en-suite.
  To elaborate, this bathroom is the other side of a big house to the water tank and the HW supply was poor. However as we have an electric shower we could live with the problem; we have a jacuzzi bath in another bathroom that my wife prefers anyway. The water supply in the other 2 upstairs bathrooms was adequate - but not great.
  Well I finally succumbed to pressure(pun intended) from wife and have just had the en-suite bathroom completely re-fitted; this entailed fitting new ceramic mixer taps to the bath and basin. We now have nothing more than a trickle of HW from both taps!! - totally inadequate.
  The plumber said this happens a lot as the diameter of the internal pipes in the taps and aperture restrict the flow; the cold water pressure(mains) from the same taps is excellent.
  Anyway this week we are having a pump fitted to the hot water supply to this bathroom. It apparently just switches on when hot water is demanded.
  As said earlier I am slightly concerned about the noise and vibration of the pump when running but I will update this thread when it is finished.
• I for one will be interested in the outcome as having had a bathroom refitted recently we can no longer have a shower. No problem with lack of hot water it is just that the mains pressure cold is too much to let it through - apparently.
  The guys were going to install a pump initially but felt it would be necessary as my old shower worked ok.
  There is no chance of moving my HWT so a pump it looks like it will have to be. If I can ever get the bathroom mob to come back. Their after sales service is nothing short of appalling.
  The phrase "we will call you back" obviously means something different to them.
• I was going to go down the pump way but decided against it as noise and also the power of the water the lads may empty the tank everytime they have a shower. also. If they have a shower late night early morning they will wake the house up.
  The hot water runs from the tank back u into the loft. Pipes well lagged. back to the shower that has a cold suply from the header tank. This is in 22mm pipe until it reachesthe mixer tap it then reduces to 18mm input. I also took the filters out of the mixer tapes. to help flow even more. i am more than happy it manages to run a shower head and shower bar at the same time although a little pressure is lost to both.
  I even timed filling a bucket to see what shower head would give least resistance. If I had no shower head just let the water run out the pipe the bucket filled twice as fast.
• Hey guys.
  Thanks for all the responses, didnt realise they would come so quick.
  I currently have a header tank (i presume this is the cold water feed) in th eloft which is 2.3 meters above the floor height.
  The cold water pressure seems fine for both the kitchen and the bathroom. Also when i was cleaningsing my radiator top up tank i realised the pressure seemed ok.
  The H/W cylinder (which is in my bedroom) , is raised by about 70cm of the floor (bottom of the tank). I seem to have the same problem at kitchen level.
  Today i have been reading around electric pumps. I am considering having one installed however their are two issues:
  1: again the noise and vibration siuation is becoming an issue. (The tank is mounted on a box (dont know what is under it)).
  2: In some areas of the house (mainly to and from the water cylinder and the boilers they use the thick 22mm copper pipe. However in the new house fashion they use the thinner plastic pipes (not sure of the mm).
  Time to call a engineer to do the annual service and steal some ideas through polite convo lol.
  To see diagram click here
• I assume I have to get a pump as I have mains pressure cold water, it doesn't come form a tank.
  Hope the pump does the trick for you
• It was easy for us to take another feed from the header tank for the cold side of the shower. I think that when we looked you could get to bore sizes for input to a mixer shower? We went for the biggest we could. We do have a small hot water cylinder and the header tank is about 3 foot cubed? Not sure waht volume.
  Cardew.
  You do have a good head of water I can't understand why the pressure is not upto it?
  As regard the pump I supose you could box it in and mount it on some form of vibration mat. Although this will not help noise transfer down pipes. It could help if you clipped the pipe with a clip with some form of rubber to help take vibration out the pipe?