3x 300l unvented cylinders in a basement.

[rekab6969]

Hi Guys,

A house I am working on has 3x 300l unvented cylinders in a basement.
There are 3x Pump House PPH-3-8L-HW pumps installed taking all three cylinders along with the central heating discharge prv.

These pumps are not correct for this installation so plan to install 1 or 2 Pump House PH-5L-HW.

The chances of all 4x prv's discharging at the same time is pretty unlikely, would one £730.00 (ouch!) pump be up to the job?

Cheers,

db.

 

[picasso]

How many people live in this house ? 900ltrs of stored hot water is a lot of water.

 

[rekab6969]

Hi,

It was a family house many years ago, it's been a retirement home in the past too, it's now being returned to a family house once again. 4x permanent at the moment but they have lots of people visit, staying over etc..
Not at the moment though..Obviously..

Heating system has 55x rads to give you an idea on it's size.. three floors.

db

 

[picasso]

No drainage running through the basement ?

 

[rekab6969]

None, there is a sink in another part of the basement and that is on it's own sump pump, bigger than the ones they installed for the cylinders as it happens..

 

[rekab6969]

Hi Guys,

Anyone know the l/m of a 6 bar 3/4 prv..?

Thanks,

db.

 

[rekab6969]

On talking to the cylinder people, 3/4 prv will discharge 28l/m, the pumps can handle 32l/m, as there are 3x cylinders the chances of more than one prv discharging at the same time is unlikely, will one pump do the job..?

Answers on a postcard..

Cheers,

db.

 

[picasso]

If the basement is empty, not furnished or used for storage then One pump should be ok, I would get a disclaimer from the owner setting out the risks versus costs and let them make the final decision.

 

[DP]

Another way to look at it is, when things fail, they tend to fail simultaneously. What I am saying is, if there is a system component that is poor, when that fails, others could fail soon after. Then the fact the cylinders are in the basement, with one pump to service three cylinders, basement could easily become a swimming pool.

Good call to let customer decide.

 

[rekab6969]

Only a few bottles of wine, slowly diminishing of late.. I'm happy to go with the one myself, customer will go with my recommendation,

 

[rekab6969]

Sorry DP, posted my last reply out of sync. I hear what you are saying, and I'm going round and round in circles, talking to three different manufactures along with the pump people too.
Only hard facts I have managed to obtain is flow rate of incoming main rated to pump out flow rate.. At best incoming is going to be 5 bar in the middle of the night, which doesn't add up as there are 3x 6 bar prv's ..?
Another states 28l/min flow rate of a 3/4 prv. in this case then that 3x pumps.. so we are covered if all three decided to discharge simultaneously. Actually 4x pumps to include the heating prv..

Off to bang head against a wall..

 

[muggles]

Those Pump House unvented discharge pumps are feckin useless in my experience. I've got a customer with one, and every year when I go to do the service it's seized, so I have to strip it down to get it going again. There's sod all chance it'll actually work when needed. Satisfies the regs and your duty of care, but ultimately a waste of £700. Pumps just don't like to be sat idle for that long

 

[rekab6969]

Any other pumps that can do the job..? Head really hurting now.

 

[sjmac]

What about adding solenoids to cyl cold feeds,link solenoids via high limit float switch. Or just single solenoid depending on main incoming pipe size

 

[Emit]

A power failure will never stop a prv from discharging , think of it that way. Only way you can is with a solenoid powered open as stated, seen a spec of a Galvenised tank and float switch with high temp sump pump. Should it fail A float switch will cut power to The solenoid. If power fails then no water of course. But nothing is fool proof, I had this argument with a few boiler manus that combine a prv into the condense pump. ok if pump is linked to the boiler etc. But in a power failure it won’t stop a letting by prv from going tits up