PRV valve!!

barry181091

Hi there,

We have an open fire with a back boiler (I think) behind it. We have a fire on now but one of the little ones running around here found a red valve to the side of it and turned it. Water started pouring out, but I eventually turned it the other way and it went to a trickle.

Turning it more has the water gushing out again, pulling it has it gushing and pushing it does nothing.

I have found out it's an RWC 3 bar PRV, this one I think;

http://www.hvacwarehouse.co.uk/type-1915-1-3-bar-pressure-relief-valves-1/

What do I do!?

John T Carroll

barry181091 wrote: »

Hi there,

We have an open fire with a back boiler (I think) behind it. We have a fire on now but one of the little ones running around here found a red valve to the side of it and turned it. Water started pouring out, but I eventually turned it the other way and it went to a trickle.

Turning it more has the water gushing out again, pulling it has it gushing and pushing it does nothing.

I have found out it's an RWC 3 bar PRV, this one I think;

http://www.hvacwarehouse.co.uk/type-1915-1-3-bar-pressure-relief-valves-1/

What do I do!?

The red knob when turned anticlockwise opens the valve, if you just turn it slowly anticlockwise until a little more than a trickle issues from it and just let it go "smartly" and then turn it a tiny bit clockwise then it should reseat after a few operations, if not, I'm afraid theres a bit of crap under the seat and it must be replaced after first draining down the system.
Edit: Firstly just turn it a tiny bit clockwise until you feel a "stop" then do what I said above.

Wearb

OP.....That price there is ridiculous. About 1/10th of that price would be nearer the mark.

corkgsxr

They Cost about a 5er.

It's on a cam so as you turn it, it will open and close. If you go full open and quickly to closed alot of the time they stop leaking

Wearb

Forgot to mention; don't be tempted to plug it. It is a safety device. If you have a trickle, just collect it in a bottle or bucket.
Corkgsxr's idea is well worth a try. Make sure you know how to turn off your heating water supply, just in case it goes pear shaped.

Calahonda52

barry181091 wrote: »

Hi there,

We have an open fire with a back boiler (I think) behind it. We have a fire on now but one of the little ones running around here found a red valve to the side of it and turned it. Water started pouring out, but I eventually turned it the other way and it went to a trickle.

Turning it more has the water gushing out again, pulling it has it gushing and pushing it does nothing.

I have found out it's an RWC 3 bar PRV, this one I think;

http://www.hvacwarehouse.co.uk/type-1915-1-3-bar-pressure-relief-valves-1/

What do I do!?

at the risk of being banned, since u in maynooth ANY LOCAL PLUMBING SHOP OR PLUMBER WILL HAVE WHAT YOUR AFTER
re the cost comment , that was for 1.25 inch

John T Carroll

Wearb wrote: »

Forgot to mention; don't be tempted to plug it. It is a safety device. If you have a trickle, just collect it in a bottle or bucket.
Corkgsxr's idea is well worth a try. Make sure you know how to turn off your heating water supply, just in case it goes pear shaped.

Slight off topic but with reference to a Oil Fired System, would it be a normal practise to operate this cam operated PRV during a Boiler Service to ensure that its at least capable of opening and isnt stuck shut?. I vent mine every six months but this is more of a routine than anything else. I have a combined cold feed & vent and on the very rare occasions that I have to drain the system down I find it fairly easy to get rid of any air by throttling the feed (1/2 ins gate valve fitted) to the header tank, filling the system very slowly and by leaving the PRV opened until the air is vented from the Boiler.

Wearb

In the beginning I used to operate the prv. It is supposed to be done. I quickly learned to leave them alone. Most systems are too dirty, due to bad installs and poor maintainence.

If they were to be checked every service and leaked afterwards, the customer is VERY reluctant to pay for all the extra work involved, including rads not working on what may have been a finely balanced system (mostly due to extra rads having been installed). 💔😰

John T Carroll

That makes sense alright as one could spend a 1/2 day venting them afterwards, if you tried to fill my system fast (without throttling the feed) and doing a few more knacks, you could literally take days to get rid of all the air eventually.

Dtp1979

John T Carroll wrote: »

That makes sense alright as one could spend a 1/2 day venting them afterwards, if you tried to fill my system fast (without throttling the feed) and doing a few more knacks, you could literally take days to get rid of all the air eventually.

No offence to you but it must be a badly piped/designed system if that's the case

John T Carroll

Dtp1979 wrote: »

No offence to you but it must be a badly piped/designed system if that's the case

Possibly, but it only takes around an hour from start to finish if I do it my way, I think if you try to do it with a full flow to the header tank that the problem is that the air is trying to vent up through a pipe thats more or less full of water, thats my story anyhow, a few neighbours with the same systems had much the same problems until they throttled in the filling flow by either fitting a 1/2 ins valve or partially tying up the ballcock (messy). It certainly gets rid of all the air because I have 3 bedroom rads which are 38 years old but I do and always have put an inhihitor into the water.