Oil Boiler Pressure Drop

OREGATO

Hi guys,
Hoping to get some advice. Live in a 2 story 4 bed semi detached house.
We moved in 4 years ago and got the gunbarrel piping replaced with copper and qualpex and also had the system zoned into 3 for hot water, downstairs and upstairs.

Since getting the pipes replaced, every now and again, I would have to go to the hot press to let water into the system as the pressure gauge would drop down to close to zero from 1.5 bar. We don't use the heating much and only use the hot water and downstairs primarily. So I'm concerned that there is a leak, it's obviously losing water somewhere right?

The last time I filled up was a month ago. The gauge was reading just above the 0 and I filled it up to 1 bar, we didn't use the heating much over Christmas but I kept an eye on the gauge and it has dropped down again to the same level. I can't see any visible leaks from radiators or ceilings or in the boiler house and the upstairs heating has probably been used twice. So I'm wondering if it's an issue with the downstairs or hot water plumbing?
It appears to lose pressure only after the heating/hot water has been on and has cooled. When the heating is on, the pressure will rise a further .5 bar.

We have three rads downstairs, hall, sitting room and kitchen/dining room. The kitchen/dining room is tiled so it would be hard to get underground to take a look without ripping out the tiles

Radiators appear to be fine and heating up as expected with no air when I try to bleed them. Only exception is the radiator in the upstairs bathroom which seems to have a bit of air, possibly because it's a rail radiator but again, the upstairs is rarely on.

So I guess my question is, should I be worried that there is a leak under ground? What is my best option? To get a plumber in to start trying to find a leak or am I best to get one to use a sealer solution?

Any thoughts or help would be greatly appreciated.

Wearb

Well your best option would be to get a plumber in, but not to start finding a leak, as there may not be one. Explain to him as you have above and let him decide on what the problem is. It might be just an under/over pressurized expansion vessel, or even a damaged one. It could be a pressure relief valve letting by.

If you know where your pressure relief valve is, you could monitor it to see if that is where the water is getting out.
Having upstairs on or off isn't significant in your case.

OREGATO

Thanks Wearb. Hopefully will have a plumber out this week to take a look. I'm hoping it's going to be something simple like the expansion vessel or the pressure relief valve. Are they prone to failing so soon ~ 4 years?

The only reason I mentioned the upstairs was that because we haven't had the heating on upstairs, it's less likely theres a leak upstairs was my reasoning as the upstairs zones/pipes would not have been circulating. Fingers crossed it's not a major issue.

Hypothetically speaking, what would happen if the pressure dropped to 0? Would air start getting introduced into the system? I believe an oil burner wouldn't stop working because of zero pressure whereas a gas boiler would?

agusta

pressure relief bar.jpg
Do you see a valve like this near the boiler
If the pressure drops to zero, air will be introduced into the system.The boiler will cut out on thermostat and can trip the hi-limit thermostat
What does the pressure gauge read when the rads are up to full heat

Wearb

OREGATO wrote: »

Thanks Wearb. Hopefully will have a plumber out this week to take a look. I'm hoping it's going to be something simple like the expansion vessel or the pressure relief valve. Are they prone to failing so soon ~ 4 years?

The only reason I mentioned the upstairs was that because we haven't had the heating on upstairs, it's less likely theres a leak upstairs was my reasoning as the upstairs zones/pipes would not have been circulating. Fingers crossed it's not a major issue.

Hypothetically speaking, what would happen if the pressure dropped to 0? Would air start getting introduced into the system? I believe an oil burner wouldn't stop working because of zero pressure whereas a gas boiler would?

You never can tell when these things will give trouble, so 4 years wouldn't mean that it shouldn't happen.

Even with heating off, upstairs will still be subject to system pressure, even when the water isn't circulating.

Agusta has answered to other question below.

OREGATO

Thanks both, good points.

Yes, there is a pressure relief bar beside the boiler, there is no visible signs of water coming from it and appears to be bone dry.

@Agusta, the pressure when the rads are up to full heat is just below the 1 bar mark.

OREGATO

Wearb wrote: »

Even with heating off, upstairs will still be subject to system pressure, even when the water isn't circulating.

Ah, I never realised this, I thought because the valve would be closed for upstairs, there would be no pressure upstairs but guess the system would always be pressurised. Learn something new every day