booster pump?

[davidmj]

Hi all,

Moved into new flat in need of major refurbishment, so money's mega tight!

No gas supply, and storage heaters (which are fine), hot water comes from an unvented combination cylinder (big cylinder with expansion vessel on top?). Cylinder works fine, loads of hot water, only problem is the flow, which is bearable at the kitchen sink, but at the bath it's pathetic. I thought about getting a booster pump like the salamander CT50 but after speaking to salamander they said it can't be used with my type of tank, as it would cause it to implode!

Any ideas? Can't afford an electric combi boiler at hundreds n hundreds of £££'s, so all suggestions very gratefully received.

Thanks.

Dave

 

[Madrab]

What you have will be a vented combination cylinder like this - http://www.coppercylinder.co.uk/1400-x-450-direct-combination-tank-economy-7.html
The cold water supply for the hot water cylinder is on top, it isn't an expansion vessel. It's gravity fed and immersion heated (2) I assume (Economy 7) so that's why the pressure and flow is pants.

You could pump this type of cylinder, it wouldn't implode, just feed the pump from the hot supply pipe as it utilises an essex type flange though I would advise against it. The issue you have is because the cold water tank on top is so small, it would be hard pressed to keep up with the demand for water into the hot cylinder that a pump would place on it, run the pump dry and you can easily damage or destroy it

 

[davidmj]

Thanks Rob, that's exactly what we've got. If it's not a good idea to pump it - which I understand now, thanks for explaining it - are there any other options to increase the flow?

Ta

Dave

 

[Madrab]

On a tight budget Dave I don't think so. In a flat the only real options you have are -

1. Combi boiler
2. Direct Unvented hot water cylinder - runs from the mains so water pressure/flow is the same as mains
3. Larger cold water tank with standard vented hot water cylinder and then pump that.
4. Thermal store...but that's another expensive story


Those are really all the options I think and they'll all cost a fair few buckeroos unfortunately.

 

[Agile]

Not to give improved flow for more than perhaps 1/2 minute.

You need an unvented cylinder if the dynamic supply flow is adequate.

Or a storage tank and cylinder.

Tony

 

[davidmj]

Thanks guys. Would this do the job? Presumably there'd be no need for a pump or other tank? so this would pretty much be the final cost (plus the plumbers time of course!)

http://www.discountedheating.co.uk/...y=GBP&source=gg-gba-pla_BeModern-All-Products

 

[davidmj]

Ok, so we've bitten the bullet and are resigned to replacing the existing cylinder. Am I right in thinking my plumber can connect this direct to the mains, and the hot water will come out at mains pressure, no other tanks, kit, pumps, etc needed? Thanks again guys.

http://www.heatandplumb.com/acatalo...m=GoogleBase&gclid=CNCXhs_oj7sCFWTnwgodSGEAUg[/url]

 

[Agile]

They can only be fitted by those who have done the G3 course!

But did you read what we have said above?

Have you had the flow and dynamic pressure measured?

Tony

 

[davidmj]

Hi Tony,

Yes I asked my plumber to check the pressure and dynamic flow. Apparently it's 2.7 bar? I'll check that he's G3 qualified.

Thanks again.

Dave

 

[Madrab]

Yes, definitely check that he is suitably qualified to installed an unvented hot water system David, not worth your or yours or your neighbour's safety if he isn't.
Ask to see his qualy's.

 

[Agile]

2.7 bar is merely the static pressure! Quite good though.

The only measurement that counts is the dynamic pressure and flow.

You would hope for at least 22 litres per minute @ 1.0 bar.

Tony

 

[davidmj]

Thanks Tony & Rab,

Not very scientific I know, but have a 12 litre bucket, which took just under 30 secs to fill, so i'm guessing around 25 litres a min?