Pressure reducing valve on filling loop

  • Thread starter GeorgeBramwell
  • Start date
G

GeorgeBramwell

I came across a pressure reducing valve on the inlet to a filling loop set to 1 bar and the filling loop valves left open. It worked in that the pressure in the system did not go above 1 bar in the CH system.

I mentioned it to another fitter and he said he had come across it a few times. I know this is technically illegal because the filling loop should be disconnected. Both of us naturally quizzed the customer on who and when it was fitted. All were fitted Spring or Summer, when heating is not on. We came to the conclusion that the fitter in order to avoid a come-back to refill the system pressure when the system settles when the CH comes on. The service fitter will pick it up when they get a service contract and turn off the filling loop. Or, to avoid ripping up the place in order to find a minute water leak under the floors on the system.

Anyone else come across it? Quite clever, as it is auto top up. If the PR failed then the pressure vessel could burst as the system may go way over 1 bar, so not recommended.
 
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Anyone else come across it? Quite clever, as it is auto top up. If the PR failed then the pressure vessel could burst as the system may go way over 1 bar, so not recommended.

something else would let go afore the ex vessel

and it is acceptable in some countries
 
D

dextrous

So, if a leak occurred somewhere, it would be a permanent feature, and flush out any inhibitor over a period of time. It would also potentially contravene the "excessive consumption of water" part of the regs.

Clever, eh? :confused:
 
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On large systems I do this while I'm bleeding to save keep going up and down stairs to top the system up. Valve comes out before I leave though.
 
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i have seen before but only as a means of convenance for people who are disabled or impaired
 
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I seen this a few times and always removed them. It's usually a sign that there is a leak somewhere. The two big problems of these botches are the leak is not fixed and the system is been constantly been topped up with oxygen/mineral rich inhibitor free water. Within months this can lead to scaled up heat exchangers (primary and secondary), leaking PRVs etc. Is the PRV leaking by any chance?
 
G

GeorgeBramwell

I seen this a few times and always removed them. It's usually a sign that there is a leak somewhere. The two big problems of these botches are the leak is not fixed and the system is been constantly been topped up with oxygen/mineral rich inhibitor free water. Within months this can lead to scaled up heat exchangers (primary and secondary), leaking PRVs etc. Is the PRV leaking by any chance?

It is all perfect - it held the charge when I turned off the filling loop. I assumed it was to prevent a call back in the guarantee period to recharge the system as it settled. The cost of a call back is a lot more than a pressure reducing valve.

As to a leak, a large leak would be seen, a weep maybe not and the same situation is with and F&E tank, so not as great a problem as you might think. 1 litre of X-400 can do a large system, so a smallish system can take some top up occasionally.
 
D

dextrous

With an FE tank, at least you'd be able to see at some time if the system was losing water due to dripping/running ball valve, but not so through the PRV unless you have exceptional hearing. Also a largish leak may not be seen if it's underfloor at ground level. But you know this already.
 
G

GeorgeBramwell

With an FE tank, at least you'd be able to see at some time if the system was losing water due to dripping/running ball valve, but not so through the PRV unless you have exceptional hearing. Also a largish leak may not be seen if it's underfloor at ground level. But you know this already.

I have had leaks where the leak was only when the system was on and hot, stopping when off. The leak was so small most of the damp evaporated off the pipe. There was no visible sign of a leak, only the pressure very slowly dropping. Took an age to find the leak. In this case, I am not saying do this, a well dosed system with inhibitor and the pressure reducing valve would stop the boiler cutting out in mid-winter. How about a small shock arrestor vessel between the pressure reducing valve and the system filled with inhibitor, then only inhibitor is being injected into the system?
 
D

dextrous

. How about a small shock arrestor vessel between the pressure reducing valve and the system filled with inhibitor, then only inhibitor is being injected into the system?

This could all be incorporated into the new quasi-magnaclean heatplate with electromagnetic loop feature (which will only operate when heat is called for) I'm currently designing. You're full of great ideas tonight. Keep it up - I'll cut you a share of the profits.
 
G

GeorgeBramwell

The valve has:

1. A pressure reducing valve
2. Two check valves
3. Integral pressure relief valve
4. Tundish

The discharge pipe connection is "plastic". The discharge pipe on a boiler
has to copper. They say it is legal to use this.

If this is the case, then a pressure reducing valve and an extra double check valve will do, as long as the boiler discharge pipe is connected. When it can be permanently connected.
 
G

GeorgeBramwell

I looked the pdf instructions. It is a check valve, then a pressure discharge valve, the a check valve then pressure reducing valve. If the check valve between the pressure reducing valve fails, then the discharge valve opens. If that fails then another check valve is in place.

A normal system discharge valve must be in place on the boiler using one of these, as there must not be a check valve between the relief valve and the system water which may be subject to high pressures.

This is easy to knock up, although it might be a bit bulky. I would fit:

a check valve,
pressure reducing valve,
pressure discharge valve,
then a check valve.

If the last check valve fails, then the pressure relief valve blows as the first check valve should hold the pressure and prevent contaminated water entering the cold water supply. The pressure reducing valve keeps the pressure below the relief valve if the mains pressure is high.

Anyone know what the Arrow valve costs? I dont know what arrow charge for their valves. This can be knocked up cheap enough.

Just a thought. Those who said they removed pressure reducing valves, where you removing an Arrow valve?
 

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