Boiler pressure problem - 4bars!

rsynnott

Hi,
I have a Potterton Suprima 50 boiler. I noticed that a couple of radiators upstairs weren’t heating fully, and the pressure gauge was showing zero (though the system was still working) so I bled the radiators, and brought the pressure up to one bar. The system seemed to work, but the pressure went up, and up... By the time I noticed and turned it off it was reading nearly 4 bars.

From reading about this, it looks like the pressure vessel should have prevented this, and if it didn’t the pressure relief valve should have. I can’t find evidence of either, though. The boiler is downstairs in the kitchen, and the pressure gauge, fill loop and pumps are upstairs directly above it. There’s nothing that looks like a pressure vessel, and no obvious relief valve either. Could the vessel and or valve be internal to the boiler?

Is this unsafe to use at this point? Once it’s cooled down would it be safe to rlelease pressure and bring it back to like it was until I have a chance to get someone to look at it? It’s been running like this for a year or so, and when I got it serviced in January the guy servicing it didn’t mention anything strange about it.

Also, is the thing in the attached photo a pressure relief valve?

K.Flyer

The item to the right of the pressure gauge is an Automatic Air Vent.
The Suprima does not have an internal expansion vessel or pressure relief valve.
You are correct that there is an issue with the expansion vessel, wherever it may be (check the attic), but an even bigger issue that the relief valve did not open.
I would recommend that don't use the system until you get someone to look at it and rectify the problems, as you are risking putting undue pressure on components that could result in leaks and water damage to your property.

rsynnott

There's no attic. Looking more carefully the pressure gauge etc isn't right above the boiler (the pipes come up to it through the concrete floor), so possibly it's in the ceiling of the kitchen or something... I only moved in a year and a half ago, so have no idea how it was all installed in the first place. I'll ring a plumber in the morning, anyway. Thanks for the help.

rsynnott

So after I turned it off, it slowly fell back to 1 bar, then overnight fell to half a bar. I don't _think_ there's a leak, though it's possible, of course. It had been running with a reading of 0 bar for ages. Is it possible there's something wrong with the pressure gauge itself?

rsynnott

Well, I figured out where my excess pressure was going anyway; a little pool of water below the boiler... One of the pipes coming out the top is also looking a bit dodgy (photo attached). Hopefully it isn’t dead; I only got a new fan put in last year...

Anyone know how old a Potterton Suprima (the older one, not the efficiency one) would typically be? If it’s 20 years or something I’d resent the possibility of having to replace it less

rsynnott

Update on this; I had a plumber out to add a pressure vessel (the system really didn't seem to have one at all) and fix a couple of leaky valves above the boiler. He couldn't see anything wrong with the pressure relief valve. Pressure now goes to 2 bars or a little over when the system's running.

However, pressure still seems to drop off. Yesterday morning, it was at 1 bar. Yesterday evening, 0.9 bar. Now, 0.7 bar. I can't find any other leaks, and there doesn't seem to be any water coming out of the pipe from the pressure relief valve (unless it's very slow). It's possible there's an underfloor leak, I suppose, but I'd have thought I'd have noticed it. Is there any other possible cause of dropping pressure that I'm missing?

Dtp1979

rsynnott wrote: »

Update on this; I had a plumber out to add a pressure vessel (the system really didn't seem to have one at all) and fix a couple of leaky valves above the boiler. He couldn't see anything wrong with the pressure relief valve. Pressure now goes to 2 bars or a little over when the system's running.

However, pressure still seems to drop off. Yesterday morning, it was at 1 bar. Yesterday evening, 0.9 bar. Now, 0.7 bar. I can't find any other leaks, and there doesn't seem to be any water coming out of the pipe from the pressure relief valve (unless it's very slow). It's possible there's an underfloor leak, I suppose, but I'd have thought I'd have noticed it. Is there any other possible cause of dropping pressure that I'm missing?

Radiator valve leaking. Take off the white caps and see if any are wet.

rsynnott

The TRVs, or the ones on the other end? The ones on the other end seem to be attached with a screw (pic attached). Do you undo that to take tm off, or are they meant to come off at all?

Sorry for all the questions, no clue what I’m doing I had electric heating until recently, not used to central.

rsynnott

Pic of the cover

Dtp1979

rsynnott wrote: »

Pic of the cover

Yes unscrew the screw and lift the cap off. Check all valves. No need to remove trv heads

rsynnott

Thanks for the tip. Looked at all covered valves, no leak.

However, after that I went around every exposed bit of plumbing looking for corrosion, and found a leak on top of one of the motorised valves (photo attached). Dunno how I didn't notice it before, must just have missed it. With the pressure at 1 bar it seems to ooze to coat the top of the nut and then stop. However, with the system running (it gets to about 2 bar running), a small drop emerges every few seconds, and runs down the side of the connection to the valve's motor unit, and down the pipe. The pipe then goes straight into the (concrete) floor. Surprised it hasn't caused more visible damage, really. Now got a cloth wrapped around the pipe catching it.

I'm a little bit concerned I might have made the problem a bit worse accidentally by wiping some corrosion off the nut on top. Does this sound likely? Is there anything I should do to patch it up until I can get a plumber out, put some blu tac on it or something?

Thanks for all the help, btw.

Dtp1979

rsynnott wrote: »

Thanks for the tip. Looked at all covered valves, no leak.

However, after that I went around every exposed bit of plumbing looking for corrosion, and found a leak on top of one of the motorised valves (photo attached). Dunno how I didn't notice it before, must just have missed it. With the pressure at 1 bar it seems to ooze to coat the top of the nut and then stop. However, with the system running (it gets to about 2 bar running), a small drop emerges every few seconds, and runs down the side of the connection to the valve's motor unit, and down the pipe. The pipe then goes straight into the (concrete) floor. Surprised it hasn't caused more visible damage, really. Now got a cloth wrapped around the pipe catching it.

I'm a little bit concerned I might have made the problem a bit worse accidentally by wiping some corrosion off the nut on top. Does this sound likely? Is there anything I should do to patch it up until I can get a plumber out, put some blu tac on it or something?

Thanks for all the help, btw.

If you can get your hands on a spanner to fit that nut. Give it a turn clockwise and hold the valve body with your hand. That should solve it

rsynnott

Dtp1979 wrote: »

If you can get your hands on a spanner to fit that nut. Give it a turn clockwise and hold the valve body with your hand. That should solve it

Seriously, that simple? Will def give it a go, then. I assumed the nut itself would probably be damaged.

EDIT: Don't have a big enough one, as it turns out. Will get one tomorrow and give it a go.

Dtp1979

rsynnott wrote: »

Seriously, that simple? Will def give it a go, then. I assumed the nut itself would probably be damaged.

EDIT: Don't have a big enough one, as it turns out. Will get one tomorrow and give it a go.

I think a 32mm spanner is what you need

rsynnott

Just looking at it, I’m not sure if I’m going to be able to grip the hexagonal bit on the valve with a tool. Is holding the valve by hand enough? What are the chances I’m going to do serious damage and have a flood here?

Pete67

That looks like a Myson valve, if you remove the two screws you can just slide the actuator off, then another 4 screws will let you take the mounting plate off and then you should have no problem getting a spanner on the hex flats to prevent the valve turning as you nip up the compression fitting.

Or see if you can get a spanner on the nut on the opposite side of the valve, that way you can tighten one against the other. Better to hold the valve body though.