Central Heating Pressure Drop PRV Overflow..what to do?

manan.shah.82

Helllo,

I turned on my central heating today for a bit and noticed that pressure bar went to 0 and boiler (worcester combi 24i) was also making slight noise.

After turning off the heating, I topped up the water but within couple of minutes it went back to 0 and I can see PRV overflow pipe (I hope I got the name correct - pipe which goes outside of house) was overflowing heavily. I allowed boiler to settled down for few hours and tried the same thing but no luck.

I had the same issue last year, when pressure was dropping (when ever I turn on my heating otherwise it used to retain) because of the low pressure in EV but this time it's unusually quick and PRV pipe starts to overflow as soon as I put the water.

Is there anything seriously wrong? What basic checks i can do before I call any engineer to come and have a look.

Please help.

Thank you.

keystone

pressure in the boiler has got too high. The Pressure Releif Valve has done its job and lifted but not reseated itself properly. The only thing you can do is get someone in.

Cheers

Myser

If it's a Greenstar 24i Junior, the PRV is a right pain to get to. You have to remove the entire hydraulic block to get to it. Might be easier to fit another PRV downstream. Of course, you need to find out why it lifted in the first place.

maintenanceman

Try flicking the PRV valve a few times and it may re- seat itself

manan.shah.82

Thank you for prompt response.

Does checking the EV pressure and re-pressurise it, if required, will make any difference? Obviously I don't want to make things worse but at the same time I would like to save money if possible (last time I had someone to come pressuriser EV costed me £50 for 5 min job)..

manan.shah.82

maintenanceman wrote: »

Try flicking the PRV valve a few times and it may re- seat itself

Can you please let me know how to do that, I'm completely noobe when it comes to things like this?

Thank you.

keystone

If the PRV seat is full of carp you'll never get it to reseat itself. It needs someone in to replace it. When was the boiler last serviced?

Myser - sorry to be thick but I'm really struggling to see the point of that suggestion tbh.

Cheers

manan.shah.82

Myser wrote: »

If it's a Greenstar 24i Junior, the PRV is a right pain to get to. You have to remove the entire hydraulic block to get to it. Might be easier to fit another PRV downstream. Of course, you need to find out why it lifted in the first place.

Yes you are right. I remember when a guy came to pressurise my EV told me looks like your PRV is leaking very slight water sometimes which is not ideal but not an issue because system can retain pressure and in 24i it involves quite a lot labor to fix such a small thing so may be you can live with it...but now I suppose I don't have much choise

keystone

manan.shah.82 wrote: »

Does checking the EV pressure and re-pressurise it, if required, will make any difference?

No. You have to bite the bullet and get someone in I'm afraid.

Cheers

manan.shah.82

keystone wrote: »

If the PRV seat is full of carp you'll never get it to reseat itself. It needs someone in to replace it. When was the boiler last serviced?

Myser - sorry to be thick but I'm really struggling to see the point of that suggestion tbh.

Cheers

Boiler was serviced about a year ago..

keystone

Its due for another then and whilst he's at it he can do the PRV. Its not going to get any better until thats done.

Cheers