pressure of our hot water

[vanartio]

Help please.We are about to buy a new kitchen tap and have a power shower installed.We need some advice as to pressure of our hot water.Acouple of years ago we had a British Gas 330+condensing boiler installed with a sealed system kit.We have a cold water tank in the loft and a hot water cylinder in the bathroom.The hot water pressure has never been very good though we were told the new boiler would improve it.All the kitchen taps seem to say for high pressure.I measured the hot water flow from the kitchen tap and it was about 5 litres/minute.Can the boiler be adjusted to increase the pressure in the taps?

Thanks

 

[steptoe]

do you still have a hot water cylinder?

if yes, then the boiler has nothing to do with your hot water pressure, (in normal domestic circumstances)

is your cold water pressure good?

 

[kme]

If the cold water tank is still in use, then, as Steptoe says, the boiler has zero effect on the hot flow rate - it is purely by gravity (from the water level in the cold tank to the tap you open).

If you have a "power shower", it has a pump inside it (easy to tell, `cos they`re noisy things!) - which would fit with a gravity system.

The only options to increase the flow are:

1. replumb the hot water with 22mm pipework - awkward and challenging for DIY.

2. install a pump on the hot water pipe - not cheap, and you may need to increase the size of the COLD water tank to "keep up" with the increased flow.

3. Move the COLD water tank higher up in the house - the higher it is, the better the flow.

4. Fit an unvented cylinder - the most expensive option, short term........but, in my opinion, the best solution.

Problem is - a kitchen sink MUST have the cold water supplied from the rising main - usually entering at 2-5 bar, depending on your location....

Then you`ve got your "gravity" pressured hot water - if memory serves, every 33 ft head of water equals 1 bar - so your hot water is nowhere near the pressure of the cold. This can be a massive problem when you install a mixer tap - the cold has so much pressure, it can effectively block the hot water from mixing properly ( imagine a car waiting to get out of a side street, into a fast flowing line of cars - the spaces between the cars are big enough for your car to fit in, if you were already at the same speed as them, but because you`re stationary, they`re creating a "solid wall" that stops you entering the flow......)

HTH

KME

 

[SLIPSHOD & SLAPDASH]

Interesting senario ! Reminds me of my 1st weeks training when electrikery was compaired with how open a water tap is so how much water flows down the hose pipe.

 

[kme]

Both trades rely on physics - is there really a big difference?

Got to get it there, and get it away again, without losing any in the process!

 

[vanartio]

Thanks for the info.It seems that we will have to find a low pressure tap if there is such a thing.

vanartio

 

[Sharpend]

You can get flow restricitors that are fitted in the cold line and this helps reduce the flow. I am slightly miffed with your OP as you have said that a sealed system was installed then also mentioned cold water tank?? Perhaps you could clarify?

---------- Post Auto-Merged at 12:45 ---------- Previous post was made at 12:43 ----------

Do you have a red and or white bulbous bottle in the airing cupboard above hot water cylinder?

 

[kme]

The condensing boiler primary may be a sealed, pressurised system, but with a vented secondary - this was my assumption, based on the info provided

 

[vanartio]

Miffed?!I assume you know the definition."1. A petulant, bad-tempered mood; a huff.

2. A petty quarrel or argument; a tiff.

tr.v. miffed, miff

 

[Sharpend]

Ok smart one, let's say that your description is open to interpretation. Perhaps you would elaborate?

 

[kme]

@ sharp.

He`s right - I think "confused" may have been a better word than "miffed" - makes it sound like your upset with the O/P for his description.............

Your last post was really unhelpful to the thread...........in my opinion

 

[vanartio]

I can,t add any thing to my original description.British Gas 330+condensing boiler installed with a sealed system kit.We have a cold water tank in the loft and a hot water cylinder in the bathroom.No bottle above the hot water cylinder.

I spoke to Gloworm today,they are of the opinion that we have an open vented pressurised sealed syatem.Suggested we have a turbidity test to check if hot water pipes are getting blocked.

Plumber coming tomorrow so hopefully all will become clear.

 

[kme]

Your description works for me - I`d doubt the DHW pipework is a problem, tbh. It`s more likely to be the high pressure cold / low (relatively) pressure hot.......

The condensing boiler wouldn`t make a difference to the hot water pressure - its "different" water (i.e. the water in your boiler NEVER comes out of the taps - it just flows between boiler, tank and radiators ( if any).

 

[DarkInferno]

KME is spot on pretty much.

The only other thing you could have a look at is if there is a gate valve feeding the cylinder, that it is fully open. You could also check there is no sediment or any other debris in the tank blocking the flow of water, (but I'd guess you have a by-law 30 cold water storage tank which obviously won't have any of those issues)

As obviously any resistance will reduce current.

Also as this has always been a gravity fed system I'd assume that its already plumbed in 22mm.

Depending on how practical you are you can raise the tank, which will provide a smallish gain for free-ish, or fit a DHW pump, which will give a decent gain while still being comparitivly cheap (

 

[IzzyS]

Anyone know the way back to the electrician forum? :C

 

[Sharpend]

To the OP and members of the forum,

I believe that I owe you all an apology for my posts in this thread, as KME has clearly pointed out I was wrong, for this I apologise there is no excuse.

Thank you.

 

[kme]

Its not a problem bud - just a word used in the wrong context. We all do it, at some time or another, FCOL. Don`t worry about it