High mains water pressure need reducing?

[bodsmate]

I have just fitted a thermal store (Gledhill Torrent Solar RE) - I note the static water pressure rises to 4.6 bar in the late evening and sits around 4 bar at other times of the day - how important is it to fit a pressure reducing valve on the mains incoming? - not keen on reducing pressure if I don't need to but don't want to harm the internal coil in the store or is this not likley?

 

[Dannypipe]

I think your best bet is to contact Gledhill's technical team and ask the question.

I've only serviced Thermal Heat Stores, and never installed one, but I have downloaded all the technical bumf on every model as I carry all this (and much more) info with me on a small laptop. So if you need any litereture, just ask, or google to model name and download a PDF from Gledhills website.

For what it's worth, 4.6 bar, is high, but not seriously high. I've been at properties where it's twice that, but then they had a PRV!! Ha!

 

[Plumbstar Tom]

im sure Geldhill will recommend a PRV at 3 bar

3 bar is more than enough in my eyes as well

 

[Bernie2]

Hmm!

Might get a bit of noise or possibly wear in the coil. Which seems obvious.

Have a look at the max recommended pressures of any fittings in or on the system.

Ask yourself "What is the maximum pressure those basin, bath, sink unit taps or shower will work at?"
"What is the max pressure for the pipe fittings"

"What is the max head for the heat store" and so on.

Look for the weakest lowest pressure link in the system and if its within bounds leave alone, if its not, use a pressure reducer.

Then consider, do you really need all that pressure?

Does more pressure help wear things out faster?

It sure can make things noisier and what may seem obvious cause pipe wall erosion. I am sure if I was a pipe wall, I would prefer you pressing against me at 3 bar than 4.5.

What is the maximum recommended speed of water in a system?

Go to "Copperclub" and have look at their recommendations. They are the Copper Development Association who represent the makers of most of the copper stuff we use.

If they don't know we might as well go home

Admittedly it may all be BS info, but its free and saves buying the BS stuff.

But if your in a geek mood, go to the library and ask to see the relevant BS documents. You can find out which ones they are by looking in the installation manual for the heat store.

That way you get the genuine info.

Possibly a bit of water hammer as well.

If I am putting you off, I don't intend too. I am just trying to point you to where you can find out what you want.

From my own rule of thumb, I would say its probably okay but perhaps noisy and does wear things a bit. And usually if a washer starts to wear water hammer can make a bang like a bomb or start that maddening buzzing. But it probably makes you renew the washers faster.

The other side of things, is that its great to have a tap that probably delivers somewhere near its max and with all that pressure you can probably have more than one tap on at once and still have good pressure. Not only that, you can use as many elbows as you want and the furthest away fittings get a bit of water as well.

Not a very scientific way to think of things though and having loads of elbows is not recommended.

Good Fortune

 

[bodsmate]

Thanks for the replies, I checked with Gledhill (well the manual!) and it does say fit a PVR set to 3bar if the pressure is above 3.5. I have now fit a PRV and set it to 3.5bar. There is a noticable drop in pressure and flow rate but still more than adequate and pipe noise is much reduced

 

[fuzzy]

youve made the right decision, the highest i ever witnessed was 7 bar! crikey

 

[oldplumber]

sww bored out all the mains a few years back and renewed pipes etc. when i was converting some flats, the inspector came to check the supply pressure leading upto to the building as it was over 4 floors, no problem tho, the standing pressure in the main in the road was 15 bar!!!!!!!!!!!!!!!!!!! so all the flats have prvs or the ceramic taps just collapse! When they first reinstated supplies in the road several of the houses had blowout in the pipework and valves, which isnt surprising!