Plumbing question

[ukwill]

Wonder if anyone can help?

My outdoor tap on the front of the house is directly off the mains feed. As such it has decent pressure and flow.

My garden taps at the rear are fed from an unvented cylinder (megaflow) in the garage. Their pressure & flow is a lot worse.

I think this may be to do with a PRV on the downstream side of the megaflow (but I'm not a plumber so don't know, hence asking!)

Any suggestions for how to get the same pressure to my garden taps? Is it possible off of the megaflow, or will I have to somehow T-off from the mains feed side of the megaflow?

[Simpo Two]

ukwill said:

Any suggestions for how to get the same pressure to my garden taps? Is it possible off of the megaflow, or will I have to somehow T-off from the mains feed side of the megaflow?

You could run a pipe round the side of the house from front to back. Just to remember to drain it in freezing weather though.

[ukwill]

Simpo Two said:

You could run a pipe round the side of the house from front to back. Just to remember to drain it in freezing weather though.

Thanks but I dont want to run a pipe externally from front to rear. Im wondering if there are any options available to get the same flow/pressure being southside of the megaflow, or if the only solution is to run the pipework up to the mains feed, on the northside of the megaflow.

[b14]

If they are fed from the megaflow, are they hot taps in the garden side? Seems unusual. If they are from the megaflow then they should have the same pressure as the mains, as that is how an unvented cylinder generally works - the fact that they are fed from the megaflow is therefore unlikely to be the reason for the difference in flow, it'll be something else to do with the plumbing of the taps

[Simpo Two]

b14 said:

If they are fed from the megaflow, are they hot taps in the garden side? Seems unusual. If they are from the megaflow then they should have the same pressure as the mains, as that is how an unvented cylinder generally works - the fact that they are fed from the megaflow is therefore unlikely to be the reason for the difference in flow, it'll be something else to do with the plumbing of the taps

The little plastic anti-return widgets they put in taps these days are guaranteed to knacker the flow. Maybe that's a factor.

[ukwill]

I just had a look.

My garden tap is coming off the cold feed which also goes into the cylinder. There is a Caleffi PRV & Monobloc manifold on this feed, in front of the connection off to the garden tap. I believe this sets pressure to 3-bar. My garden tap shows 2.7 bar. My front tap shows 7 bar.

I think the issue is the garden tap should be connected before this PRV, and not after it.

But I'm not a plumber, so it's just a guess.

Will call a plumber!

[Sheepshanks]

Mine are the same too - always surprises me when I open the garage tap as water blasts out.

Back garden one is just connected back to back with kitchen sink, so off the balanced feed. It's just about good enough as our garden is fairly small.

[Brinyan]

You’re right that the Caleffi valve reduces the pressure into the unvented cylinder - it’s a combination valve, consisting of filter, pressure reducing valve, pressure relief valve & non-return valve, all in one fitting. If you take the supply to the garden tap/s off before the combination valve, you’ll have the same pressure as the other outside tap.

[Simpo Two]

ukwill said:

My garden tap shows 2.7 bar. My front tap shows 7 bar.

How did you measure those?

[ukwill]

Simpo Two said:

How did you measure those?

With one of these - https://www.amazon.co.uk/Silverline-482913-Mains-W...


Cheers all - plumber booked for next week to sort and do the boiler service whilst he's at it.