Worcester boiler - 0 pressure

illusionek

Hello

I have just moved this week to my first house and I am at a loss when it comes to my boiler, so I hope someone could help me out.

My boiler is Worcester Greenstar 24i Junior. Not sure how old if I was to guess probably 7-8yrs.

When I moved in the pressure gauge was at about 1 bar, right at the border between red and green and Central Heating was not on. It stayed like this for the first couple days.

Then I put CH on last night and the pressure increased to about 3 (bored of red/green again) bars when working, which I believe is also fine. However I noticed that the pressure dropped right to 0 within about 90 min since switching off CH.

The hot water seems to be fine even with 0 pressure and I was very surprised that CH is also working when I put it on this morning. The pressure increases to 3 again when working and dropping to 0 within 90min when CH is off.

I am at complete loss here as I was under impression there should be no hot water or heating with 0 bar. Also do not understand that sudden drop all seemed to be working fine before I put CH on for the first time. I cannot see any leaks or anything explaining explaining this.

The other thing is I cannot re-pressurise the boiler as the tap/handle seems to be stuck, I cannot turn it. I think I do all correctly as I followed below link on Worcester website. So I am not sure if this is a separate or connected issue.

However even if I could re-pressurise then potentially pressure would go way above 3 bars if now goes from 0 to 3 when working.


https://www.worcester-bosch.co.uk/support/troubleshooting/faqs/home-heating-faqs/how-often-should-i-need-to-top-up-the-pressure-in-the-heating-system

glentoran99

chances are you have a leak somewhere

Alex1983

Your expansion vessel needs checking, suspect it's flat and that's why the pressure went to 3 with the heating on, when it went to 3 in probably starting discharging out the pressure relief pipework, a small copper pipe sticking outside somewhere.

illusionek

I am new to the whole subject so may be asking silly questions, but I would think pressure would be at 0 when I moved in rather than dropping to 0 after I used CH for the first time? Also how is it possible that the boiler still provides CH and hot water at 0 bar? I was under impression I would need to re-pressurise first?

Also finally how do I go about finding a leak? Boiler cupboard is fine and I could not see anything around radiators. Also no stains appearing on ceilings and cannot see any water gathering outside of the property.

illusionek

Alex1983 Your expansion vessel needs checking, suspect it's flat and that's why the pressure went to 3 with the heating on, when it went to 3 in probably starting discharging out the pressure relief pipework, a small copper pipe sticking outside somewhere.

Is it something I can do myself or need to get a plumber? If DIY what exactly do I need to do?

Alex1983

Your boiler has no low pressure cut off so it will work on 0 but risks it overheating and been noisy.

If the boiler has dumped water outside though the pressure relief pipe then it's likely that the pressure relief valve will need replacing, which is a very fiddly job on your boiler. You need a gas safe person to sort this.

If you can see the pipe outside then you could tape a small sandwich bag to it and put the heating on for a while and see if any water collects in it, this will prove your fault.

illusionek

I can see the relief pipe but boiler is on the first floor in one of the bedroom, so I am not able to access the pipe even on the ladder. I checked outside and no obvious signs of water.

I signed up to a service plan with Worcester but it does not kick in until next month, if there is a risk of overheating then I guess I cannot wait that long and I need to fork out for a plumber to come in and have a look otherwise I may need a new boiler?

fred246

I had a leak on my system for years that no-one could work out. Then one day eleven years ago I spotted some water under the boiler. I was covered by Domestic & General so they sent out a CORGI engineer. He diagnosed a leak from my heat exchanger and said the boiler was beyond economic repair. They quoted me £2k for a new boiler. Domestic & General said it was leaking before I took cover so refused to pay anything. I took a look and could see the leak from the junction of the heat exchanger and the pipe leading to it. I fixed it with PTFE tape costing 99p. The boiler is still working well.

illusionek

I guess as a minimum I should at least re-pressurise to avoid overheating. So how do I overcome this problem?

Internal Filling Key is inserted and turned to open position but I am not able to turn the white tap/valve (not sure how to call it). It is completely stuck. I am afraid to apply too much force since it is a small plastic thing and I am concerned I can damage it. I tried to turn it anti-clockwise and clock-wise and it simply does not turn at all.

Le_Kirk

Suggest you find a local heating engineer (one who is Gas Safe registered, or whichever is this week's controlling body and can also do plumbing work) who will then check/pump up your expansion vessel and replace the valves on your filling loop.

illusionek

It sounds I may have no choice, any idea how much this pleasure may cost me? I live in Greater London.