Baxi 60/100 prv leaking

Bull76

Hi Folks,

Pressure is falling on my Baxi 60/100. The outlet for the PRV is leaking water when the boiler is running. I know that this should be replaced. Question is now how difficult is it to replace the PRV. Haven't opened the boiler as of yet to investigate. It will have to wait until Tuesday when I'm not busy.
Anyone have to replace a PRV on there Baxi 60/100 boiler?

Thanks for your replies and help.

If you mean your 3 bar safety valve then it's leaking for a reason, replacing it won't do anything except put the problem off for a while, get the boiler checked and ask the engineer to look for sludge, expansion vessel pressure, etc.. the engineer will know what to check, good luck, Gary.

Bull76

Hi Gary,

Thanks for your reply. The house was built 2002, were only in it this year. The pressure gauge was nearly zero when I noticed it. Verified that water was coming out the PRV outlet, yes the 3 Bar safety valve.
Adjusted the pressure back up to 1.5. We'll see how that goes.

If it is still leaking and the boiler is not reaching 3bar you can blow water through it and try getting rid of any dirt on the seating of the safety valve, if it is reaching 3 bar then you may need the expansion vessel checked, Gary.

Bull76

Thanks Gary,

I'll have a look at it next week and update on my progress.

Micky Dolenz

Bull76 wrote: »

Hi Folks,

Pressure is falling on my Baxi 60/100. The outlet for the PRV is leaking water when the boiler is running. I know that this should be replaced. Question is now how difficult is it to replace the PRV. Haven't opened the boiler as of yet to investigate. It will have to wait until Tuesday when I'm not busy.
Anyone have to replace a PRV on there Baxi 60/100 boiler?

Thanks for your replies and help.

Bear in mind it is against the law to work on a gas appliance unless you are a registered gas installer. www.rgii.ie


changing a PRV is quite stairght forward and a good servicer will have it done in no time, as Gary states, it is a symtom of an other problem, your service person will check for causes.

Mike2010

Just out of curiosity, did you solve this problem by replacing PRV ? (I have the same issue ... ie: leaking water thru the PRV at low pressure)

Mike2010

So, the story with mine is like this. It's a Baxi 60/100 and I noticed a few weeks ago that the pressure gague was shooting up past 3 and up to the max of 4 bar on occassion!!
I noticed that there was water comming out of the pipe (due to the PRV releasing water I assumed). I got a guy in the next day to look at it, and he represurised the expansion vessel from 0.5 to 1 bar I think.
(the boiler manual says that the expansion vessel is pre-set to 0.5 which is adaquate for a 125 liter system (like mine))
But after that, I noticed that there was a constant flow out of the external pipe regardless of the pressure level. Not sure if that was the case before the guy came to fix the first issue.
Anyway, right now, and for the last few weeks, it shows 0.5 when off. it climbs to 3 when running for about 30mins, and afer that it stays around 2 to 2.5 bar. There is a constant flow of water out of the pipe though while the boiler is on or off.
The guy is coming tomorrow to replace the PRV, but I guess there is a still going to be an underlying high pressure issue. From what I've seen online the high presure is either the expansion vessel is busted or there is "sludge" in the system. Hopefully the draning of and system tomorrow will flush any sludge.
BTW:this is a closed system that is fed from a tank in the attic with a non-return valve. From reading online, I think this is a stange setup. The good thing about this setup it is that the leak has not emptied the system and caused other problems but on the otherhand, I'm sure my rust inhibitor has been long ago flushed out so who knows what damage that would have caused.
Anyway, I'll know more tomorrow after the guy replaces the pressure release valve ... fingers crossed.

Sludge wouldn't cause the high system pressure other than to block the pipe connected to expansion vessel, i would have the water looked at with the idea of some proper flushing to get the system right once you have the problem sorted, i would say your expansion vessel would have to be looked at again, if it working you won't get the kind of gauge movement you are getting especially as it not mains fed, the pressure vessel is there to absorb the increased pressure from heating the water and yours is still not, i wouldn't replace the blow off valve until the main issue has been dealt with or you will get dirt on the seating of that valve and have to replace that also:eek:, Gary.

Mike2010

I was hoping that draning the system would magically fix it somehow.
When you say to properly flush the system .. what does that mean exactly?
Considering the house is only 5 years old, would it be unusual that the boiler would have a broken expansion vessel?
When the guy came the first day he said the pressure in the vessel was 0.5bar .. which is what the manuall says it should be set to ...
If the vessel was truely broken would the pressure be Zero?

If the vessel was absorbing the pressure and was the correct size for the system, you wouldn't be getting high pressure like this, normally the only way you would get that kind of rise would be if the system was to big for the vessel, then it would show from the start, also if mains water was getting into the system then the pressure would rise, but as it's temperature related it cannot be a mains problem.

With the boiler drained(with water in it you will get a false reading) take the reading from the vessel, if thats right then take out the pipe connecting the vessel to the boiler and make sure it's clear of any sludge.
Sludge can appear in a system in under 6 months. There are different levels of flushing, from leaving a cleaning chemical in for a few days then draining, to a full power flush. Vessels can break very quickly on a dirty system, if it's high in chloride the membrane can split in months, it could always be you have a funky fault, so i would be interested to see what you find, every days a learning day, Gary.

Mike2010

Thanks Gary. I'll ask the guy to check the vessel pressure when the system is empty. I'll keep you all posted on results ... thanks for your time on this.

Mike2010

So, my pressure release valve was replaced yesterday and it does not appear to be leaking anymore. I wasnt there when he replaced it.
He replaced the valve without draining the entire system. He was able to do it by draining the boiler only. He checked the expansion vessel to make sure it was 0.5 bar when the system boiler was empty.
Looking at it last night, it seemed to be working ok. the pressure rose to 2.5 (just where the RED starts) but never went to 3.
However, this morning I noticed it was over 3 again :mad:. This is really anoying.
Assuming the expansion vessel is ok, and the fact it is fed from the tank in the attic (so there should not be excessive pressure form that) what are the other options. Would it be a good idea to block the feed from the attic by closing the gate valve and release some water from the system in order to allow for more room for expansion? What is the best way of releasing water from the system ? Thru bleeding? by turning the PRV ? or some other way?

Mike2010

Mike2010 wrote: »

Would it be a good idea to block the feed from the attic by closing the gate valve

No, the only thing that would happen is when the boiler blows off again the boiler could be damaged from lack of water because it couldn't top it self up.

Mike2010 wrote: »

and release some water from the system in order to allow for more room for expansion? What is the best way of releasing water from the system ? Thru bleeding? by turning the PRV ? or some other way?

The real level of water is the reading you get when cold, as the water is heated the pressure increases, if you release this high pressure you will reduce the level of water when cold(with the feed from attic off), if you open your new blow off valve then you risk getting dirt on the seating, probably the easiest way out would to be to fit a second expansion valve to the heating system, the first vessel cannot be working, it sole purpose is to take up the expansion you are having a problems with, Gary.

Bull76

Hi

Is the feed the fill loop from the Attic tank? Isn't it to be keep closed and only open when used to fill the system.
My fill loop is from the attic tank also, Reason I know as I had to find it as it's a new house to me, even though it is 8 yrs old.
Sorry to ask....

Mike2010

It's amazing how much time you can waste looking at a pressure needle going up and down ...
My expansion vessel is not working I think ... in fact I'm almost sure now. I turned on the heating and I saw the pressure rise to 3 again. The pipes for the heating flow and return are hot - obviously. So, I stuck my hand up the back of the boiler while it was hot to check if the pipe that feeds the expansion tank was hot. (Tight squeeze) It was not hot!
Assuming I got the right pipe (its a narrow pipe) I would have expected that if it was carying hot water into the expansion vessel that it would be hot (it's copper) ...... SO... based on that I think that there is a blockage somewhere around the point where the pipe to the exspansion vessel starts. I think I'll have to get someone new to look at this next week.

The attic feed was also fully open, so I dont see any reason to keep it closed if the system is working well. However, in my case it's just a vicious circle of the PRV letting water out and the attic tank replenishing it, and the pressure staying high (while hot).

So, my plan is to get a new guy out to look at it (maybe next week) and tell him that I want to find the root cause of the expansion vessel blockage. I feel that I'm on the right track now thanks to you guys.

Bull76

Bull76 wrote: »

Hi

Is the feed the fill loop from the Attic tank? Isn't it to be keep closed and only open when used to fill the system.
My fill loop is from the attic tank also, Reason I know as I had to find it as it's a new house to me, even though it is 8 yrs old.
Sorry to ask....

If you have a system that is connected to mains water you must turn off the filling loop to prevent the system from over pressurizing and by rights disconnected from the mains it as well.

If you have a system thats fed from a tank you must leave it open,this is so it can maintain water levels, also most boilers have the low pressure safety device cut out so they can work on this kind of system, not a problem if the tank can top up the water, Gary.

Bull76

Thanks Gary.

Bailey05

Anyone actually know how to manually release the pressure on the Baxi 60/100 boiler to bring it back in line with the recommended level? Thanks

Bull76

Hi,

The easiest way to bleed pressure from your system is to release it throught the bleed valve on a radiator. This will drop the pressure. Under No circumstances open the PRV valve. If opened it will probably never seal again and need to be replaced.

Hope this helps.

Bailey05

Bull76 wrote: »

Hi,

The easiest way to bleed pressure from your system is to release it throught the bleed valve on a radiator. This will drop the pressure. Under No circumstances open the PRV valve. If opened it will probably never seal again and need to be replaced.

Hope this helps.

Thanks, but the pressure is low rather than too high. Done the radiators, but pressure still dropping, not fast but enough toget my attention. Alot of people seem to be able to do it manually and was wonder if the same can be done on Baxi boilers?

Bull76

You need to top pressure up then not release pressure. You need to find your fill loop. This can be anywhere.
In my home, it is located in the hot press upstairs with the hot tank. It was an automatic filling valve until I replaced it as it had stuck closed.

You need to identify all pipe work going to your boiler, it will be the only one that has mains pressure in it. Sorry can't be of more help.

Bailey05

Bull76 wrote: »

You need to top pressure up then not release pressure. You need to find your fill loop. This can be anywhere.
In my home, it is located in the hot press upstairs with the hot tank. It was an automatic filling valve until I replaced it as it had stuck closed.

You need to identify all pipe work going to your boiler, it will be the only one that has mains pressure in it. Sorry can't be of more help.

Thanks for your help, trying to find the loop could be fun! If you hear of a house flooded on the news, that will be me.

Littonprc

Mike2010 wrote: »

So, my pressure release valve was replaced yesterday and it does not appear to be leaking anymore. I wasnt there when he replaced it.
He replaced the valve without draining the entire system. He was able to do it by draining the boiler only. He checked the expansion vessel to make sure it was 0.5 bar when the system boiler was empty.
Looking at it last night, it seemed to be working ok. the pressure rose to 2.5 (just where the RED starts) but never went to 3.
However, this morning I noticed it was over 3 again :mad:. This is really anoying.
Assuming the expansion vessel is ok, and the fact it is fed from the tank in the attic (so there should not be excessive pressure form that) what are the other options. Would it be a good idea to block the feed from the attic by closing the gate valve and release some water from the system in order to allow for more room for expansion? What is the best way of releasing water from the system ? Thru bleeding? by turning the PRV ? or some other way?

Having this problem of high pressure now. What was the result Mike2010

Bull76

Easiest way to relieve pressure in a system is through your radiator bleed valve or if you had a drain point that would work better. Usually when cold pressure should be around 1 to 1.5 bar. Most manuals state this.
When hot the expansion vessel allows the pressure to go somewhere when the water gets hot and expansion occurs.
hopefully you have it resolved by now.