Leaking PRV - which one?

[Amyy]

We have recently discovered that the pipe highlighted blue in the photo which leads to the engine bay has been leaking.

 

Despite what it might look like in the photo, there is absolutely no water around the PRV or the calorifer, just coming out the pipe into the engine bay 
 

I was able to twist the PRV on the left hand side but the pipe is still dripping. I have tried twisting the PRV at the bottom and when I turn it to the left it doesn’t move and when I turn it to the right it started making a hissing noise which the other one didn’t do so I was hesitant to turn it all the way

The engine hasn’t been on for over a week so the calorifer hasn’t been heated and it’s still been dripping when cold, seemingly constantly 

 

Our water pump has been running every hour or so which I assume is due to this

 

As both of the PRVs link to the pipe where the leak is coming out, is there anyway to know which one is the problem or will we need to clean/replace both of them?
 

Thanks

 

[Tony Brooks]

No idea why there are two, unless one relates to a central heating system. 

 

I can't see the pipework to trace it, but I think the higher one is for the domestic water system. 

 

Trace where the pipework to the lower one comes from to be sure.

[jonesthenuke]

Disconnect the pipework at the Tee above the  left hand PRV, Allow the water in the pipe to drain and then see which one drips?

 

That Tee looks to be a JG Speedfit or similar, to release a pipe push the collar back towards the fitting and then pull the pipe out.

 

[David Mack]

That pipe marked in blue appears to be the drain connection for both PRVs. It should lead overboard, or perhaps into a container which you empty periodically.

PRVs letting water through is what they are supposed to do if you have excess pressure in the system.

As Jones says, disconnect the tee then see which one is leaking. Then tell us what the pipework attached to the leaking PRV leads to, then we can hazard as a guess as to the cause of the problem.

[ditchcrawler]

2 hours ago, Amyy said:

We have recently discovered that the pipe highlighted blue in the photo which leads to the engine bay has been leaking.

 

Despite what it might look like in the photo, there is absolutely no water around the PRV or the calorifer, just coming out the pipe into the engine bay 
 

I was able to twist the PRV on the left hand side but the pipe is still dripping. I have tried twisting the PRV at the bottom and when I turn it to the left it doesn’t move and when I turn it to the right it started making a hissing noise which the other one didn’t do so I was hesitant to turn it all the way

The engine hasn’t been on for over a week so the calorifer hasn’t been heated and it’s still been dripping when cold, seemingly constantly 

 

Our water pump has been running every hour or so which I assume is due to this

 

As both of the PRVs link to the pipe where the leak is coming out, is there anyway to know which one is the problem or will we need to clean/replace both of them?
 

Thanks

 

You could break the pipe joint on the outlet of the PTV and see where the water comes from. 

[MtB]

One of the most useful things to have on a domestic water system is a pressure gauge. The you'd be able to read it and know if the system pressure wss getting too high leading to the PRV dribbling (i.e. doing its job, not 'leaking') or if the system presure is correct and the PRV is faulty.

 

We have them on sealed heating systems, and I've no idea why they are not fitted to all domestic water systems as well.

 

 

 

[ditchcrawler]

20 hours ago, MtB said:

One of the most useful things to have on a domestic water system is a pressure gauge. The you'd be able to read it and know if the system pressure wss getting too high leading to the PRV dribbling (i.e. doing its job, not 'leaking') or if the system presure is correct and the PRV is faulty.

 

We have them on sealed heating systems, and I've no idea why they are not fitted to all domestic water systems as well.

 

 

 

I think the one I fitted was designed for Hot Tubs 

[Ex Brummie]

PRV's can be bought with pressure gauges from any decent merchants or Screwfix, ToolStation etc. for around £10. It is worth keeping one in boat stock as they are easy to replace but you may be miles from anywhere that sells them. If the seat is calcified or 'debris'ed, A quick turn or flush rarely works as they are so cheaply made. Boat systems often suffer with undersized expansion vessels which can result in overpressure particularly when cruising for long periods.

[blackrose]

39 minutes ago, Ex Brummie said:

Boat systems often suffer with undersized expansion vessels which can result in overpressure particularly when cruising for long periods.

 

Assuming the OP's hot water system is fitted with an expansion vessel. I haven't seen anything to suggest that it is, which could at least partly account for the leaky PRV.