Filling loop and pressure reducing valve

[dmccormick]

To aid refilling the system without having to keep going outside to boiler, then back in to bleed, etc I want to add a pressure reducing valve to the filling loop.

I am wondering what sort of coupling would be needed - the PRV's I have seen are 15mm compression fittings. I am guessing one end of the filling loop would simply screw onto one end of the PRV. However, that leaves me with a threaded end of the PRV to connect to the threaded end of the filling valve.

Can anyone advise how to connect this up. Ideally I would like to be able to have the PRV connected to the filling loop such that it can be screwed into the existing filling outlet point.

Also, any advice on a PRV. Seems to be quite a range from around £20 to £50.

 

[Agile]

You are confusing a relief valve with a reducing valve.

A reducing valve has compression fittings on both ends.

You would be better off solving the leak which is causing the pressure to go down!

Tony

 

[bigpkr]

If you want to fill your heating system from the inside all you need is a filling loop, T into cold mains, T in heating return, then fit the filling kit between them.

Also add a pressure guage so you can see what your doing.

 

[Agile]

If the PRV is correctly set then a gauge is not needed. But its more expensive than a gauge.

They are sometimes fitted in tenanted properties.

I even saw one with a solenoid valve and a timeclock to top up once a week!

Tony

 

[dmccormick]

I am not confusing them. I am talking about a pressure reducing valve and how to fit to a filling loop. There is no leak to fix - I am draining the system to add a new branch. There is already a cold mains pipe with a valve on it. The filling loop screws onto thus valve and other end screws onto similar valve connected to heating circuit.
What I want is to screw a pressure red valve onto the filling loop and then screw that into the mains valve. Thus is so I can just leave it on whilst bleeding system without blowing the pressure relief valve by overfilling

 

[dmccormick]

It's really just a question about fittings and sizes:

There is a 15mm copper pipe supplying mains cold water.
At end of this pipe is a quarter turn valve with a threaded male connection.
The filling loop has a handnut that screws onto this valve.
I want to add a pressure reducing valve between the valve and the loop.

I believe that a 15mm PRV will just screw into the filling loop nut.

Then how do I connect the other end of the 15mm male thread from the PRV to the male thread on the mains water valve ?

 

[buck51]

FFS with a short piece of copper and a nut and olive!!!!

 

[Agile]

Then how do I connect the other end of the 15mm male thread from the PRV to the male thread on the mains water valve ?

A reducing valve comes with two 15mm compressing fittings.

The filling loop will replace one nut and olive.

The other end needs a short length of tube to connect it onto the double check valve.

Tony

 

[compheat]

FFS with a short piece of copper and a nut and olive!!!!

 

[dmccormick]

Sorry for being dim and providing such amusement, but a nut and an olive is not really good. I want to be able to detach the loop easily to use elsewhere without needing a spanner.

The existing loop terminates in a wing nut. By screwing the PRV into this wing nut I am left with a male thread. Is there a fitting I can screw onto this that will end with a nut that can screw onto the cold water outlet.

Would a 1/2 BSP tap connector be the right thing ?

 

[Agile]

If you follow the advice given you will still be able to undo the wing nut on the filling loop!

I think that they see YOU as the nut!

 

[Charnwood]

A reducing valve comes with two 15mm compressing fittings.

Wrong. Pressure reducing valves are available in compression and BSP threaded.

What is the 'water outlet' you want to connect the PRV to?
If you mean the 1/2" male thread of the water meter, you could use a 1/2" BSP socket along with a proprietary thread sealant.

Why would you want to detatch the loop 'to use elsewhere'?

 

[JimCrow]

Sorry for being dim and providing such amusement, but a nut and an olive is not really good. I want to be able to detach the loop easily to use elsewhere without needing a spanner.

The existing loop terminates in a wing nut. By screwing the PRV into this wing nut I am left with a male thread. Is there a fitting I can screw onto this that will end with a nut that can screw onto the cold water outlet.

Would a 1/2 BSP tap connector be the right thing ?

Use another flexi hose and fit the prv between the two hoses

http://www.screwfix.com/p/flexi-hose-1-2-x-1-2-x-300mm-bx10fpfp30s/66800#

 

[dmccormick]

Thank you Charnwood. The water outlet is a 15mm quarter turn ball valve. One end is compression fitted onto a copper pipe connected to mains cold water supply. The other end is what the wing nut of the filling loop screws onto.

What I had not realised is that the thread on 1/2 BSP tap fittings is the same as that on 15mm compression fittings.

I have solved my problem with a straight tap connector 15mm x 1/2" female, soldered onto copper pipe that is compression fitted to PRV which is screwed into wing nut.

In effect, I just wanted to add PRV to filling loop.

Reason to be able to detach is that I sometimes have to go and fix my mum and dad's plumbing and now that they have switched to a presssurised system I can envisage having to drain and fill their system as well and would be nice to be able to do this in one go instead of bit by bit.

The valve I got is an Altecnic 15/22 mm for £24 which I thought was not bad.