Help - System losing pressure after oil boiler was replaced

[SimonG]

I would be really surprised if your home cover, covers an oil boiler. Seen many a customer in the past with 'cover' to find out they're not!

 

[Stigster]

Hi,

This is not a DIY job, you must consult 'Registered Professional Gas Engineer' plumber for this issue.

It's an oil boiler matey.

 

[G M]

I would be really surprised if your home cover, covers an oil boiler. Seen many a customer in the past with 'cover' to find out they're not!

I don't see what choice I have really. There's just no way I can leave the heating off until after Christmas. I'll try and get it checked before Christmas, but it seems unlikely.

 

[SimonG]

The more you put on here the more Mickey mouse the install sounds.
Second hand boiler, un insulated pipes outside, installer not getting back to you.

Any pics of the outside of boiler and new pipework?

Might be worth trying to get hold of a decent oil guy and go from there. Bin off your installer.

Its either the ev or leaking underground pipes. But theres also something not right in the combustion chamber.

 

[Brambles]

The quickest way to test this is to drain the system and fit isolation valves to the boiler flow and return. Thereafter pressure test the boiler. From the photos you have posted, to me, it all points to boiler feed water leaking into the combustion chamber. The surfaces you have photographed should look like a slightly singed digestive biscuit - not like a barnacle encrusted hull of a boat.

Whilst I can understand that you want to continue to try to use the boiler - if the exchanger is leaking, unless the boiler is on load 24/7 (evaporating the leak at source), it will quickly fail to a point where it is unusable. The damp refractory linings / protection boards will disintegrate allowing the flame / heat to attack the inner then outer casing.

 

[SJB060685]

Exactly what I was getting at earlier Brambles, just not worded as such

 

[G M]

The more you put on here the more Mickey mouse the install sounds.
Second hand boiler, un insulated pipes outside, installer not getting back to you.

Any pics of the outside of boiler and new pipework?

Might be worth trying to get hold of a decent oil guy and go from there. Bin off your installer.

Its either the ev or leaking underground pipes. But theres also something not right in the combustion chamber.

I'll get some pics up tomorrow. I just gave it a break for this evening. The whole thing is stressing me out. I don't want to jump the gun here, but since i moved the fire board out of the way, checked all the release valves and topped up the system, the pressure hasn't dropped at all. That's about 7 hours now. It would normally be well down at this point. I'll know for sure in the morning.
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The quickest way to test this is to drain the system and fit isolation valves to the boiler flow and return. Thereafter pressure test the boiler. From the photos you have posted, to me, it all points to boiler feed water leaking into the combustion chamber. The surfaces you have photographed should look like a slightly singed digestive biscuit - not like a barnacle encrusted hull of a boat.

Whilst I can understand that you want to continue to try to use the boiler - if the exchanger is leaking, unless the boiler is on load 24/7 (evaporating the leak at source), it will quickly fail to a point where it is unusable. The damp refractory linings / protection boards will disintegrate allowing the flame / heat to attack the inner then outer casing.

What you say here makes perfect sense. The pressure doesn't appear to drop when the heat is on, likely because any water in the chamber is evaporating with the heat. It seems overnight, it drops like a stone. I never have the heating on overnight until 7am the next morning, so this is the most likely time it will happen.

Hahaha I can't help but laugh at your barnacle analogy. It makes perfect sense though. I was going to get the boiler properly serviced, but I'm thinking now I should go back to the installer (who also sold me the boiler) and ask him to sort it out. I've known him for a good few years now and I don't think he would intentionally sell me a dud boiler. If he did know, he'd be mad to fit it too.

Maybe there is some water dripping down where the fire board once was and as a result there's been a minor piercing of some kind in the combustion chamber ceiling.

Do you think it would be wise to check the chamber in the morning and turn off the heat so it doesn't come on in the morning, then see if it's wet? That way, we'll know for sure that there is water leaking into it. Like you all say, the barnacles shouldn't be there.

Thanks again to everyone for your input. I'd never find this in a million years without your help!

 

[Brambles]

GM

The pressure within the primary flow system is rather like a balloon - it either leaks or it does not. But it will leak if the skin is penetrated. Heat protection is outside the primary flow skin. Moving / removing any form of refractory lining, plates or other protection should have no immediate impact on the pressure within the primary circuit.

The boiler needs to be set up in accordance with the manufacturer’s instructions. They (oil fired boilers) should not be configured on a trial and error basis. If the refractory protection on an oil fired boiler fails, in conjunction with the fire valve not responding quickly, the effects can be catastrophic. If you want photo's I’ll post them.

Be aware that most (if not all) UK Insurers subscribe to Athena Intelligence which quickly and effectively picks up forum and web chat (open and dark) et al conducted ahead of subsequent major insurance claims.

 

[SJB060685]

You're misunderstanding what Brambles is saying. There should be no water in the combustion chamber. The water jacket surrounding the combustion chamber should not have pierced, fractured etc. If there was water in there then yes it will evaporate and boil away but you would also have lost pressure, it will not stop boiler pressure dropping, I suspect the reason why you're not noticing the pressure drop when heating is because as I said above the pressure will rise slightly when heating, even on a perfectly sound system. As we've all said, in the morning fill up, isolate boiler power so it doesn't come on and wait an hour, if pressure has dropped check inside the chamber for obvious signs, check around boiler base, check all accessable pipework and check the PRV hasn't discharged by putting a bowl under it.

 

[G M]

You're misunderstanding what Brambles is saying. There should be no water in the combustion chamber. The water jacket surrounding the combustion chamber should not have pierced, fractured etc. If there was water in there then yes it will evaporate and boil away but you would also have lost pressure, it will not stop boiler pressure dropping, I suspect the reason why you're not noticing the pressure drop when heating is because as I said above the pressure will rise slightly when heating, even on a perfectly sound system. As we've all said, in the morning fill up, isolate boiler power so it doesn't come on and wait an hour, if pressure has dropped check inside the chamber for obvious signs, check around boiler base, check all accessable pipework and check the PRV hasn't discharged by putting a bowl under it.

Sorry but what have I misunderstood? I'm agreeing that there should be no water in the combustion chamber.

So from about 5pm this evening there has been no pressure loss whatsoever. The heating has been off most of this time and normally it would have dropped considerably by now. I'll check it again in the morning to see if there's been any further loss. Thanks!
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I've just checked the gauge and it hasn't budged! It's rock solid now. I'm really not sure what caused this, but my guess would be that maybe the pressure relief valve in the vessel was the culprit. There was a couple of things I did:

• Pushed the fire board out of the way in the combustion chamber.
• Fiddled with the pressure release valve on the expansion vessel.
• Released all the pressure in the expansion vessel with the system off and re-pressurised. I accidentally overdid it a bit to 2 bar.

One of my next projects was to try and get the rad in the utility room working. It was always cold. This morning for the first time in like forever, it was piping hot. This is, to my knowledge the only rad in the house that has the flow and return pipes up the wall. All others are under floor. I would guess that the extra pressure is helping.

Is it safe to leave the system at 2 bar? The orange dial in the gauge says 1.5 so maybe the needle is not accurate and the pressure is too low to drive all the rads? I don't have the kahunas to touch it right now given the constant loss of pressure these last few weeks.

I fully plan to get the oil boiler serviced and I'm in the process of arranging someone to check it. Thanks to everyone for the great help so far!

 

[Stigster]

One thing to take into account is the small amount of water that needs to be lost to drop pressure significantly, or even to zero. I'm running an admittedly small system used for training in my workshop, 5 rads, electric boiler and unvented indirect cylinder but I was just showing an apprentice yesterday, it only takes just under 2 litres of water loss to drop from 1.4 bar running hot, to 0 pressure on the gauge.

That amount of water can be lost into a combustion chamber and evaporated in next to no time at all. Same with a PRV, only a few cups of water lost can significantly drop pressure as you can now imagine. The suggestions you've had to isolate the boiler with service valves and check there is a good one. Even doing as also suggested, topping up the system, don't run it at all and check for water in the combustion chamber will really narrow the problem down.

 

[G M]

One thing to take into account is the small amount of water that needs to be lost to drop pressure significantly, or even to zero. I'm running an admittedly small system used for training in my workshop, 5 rads, electric boiler and unvented indirect cylinder but I was just showing an apprentice yesterday, it only takes just under 2 litres of water loss to drop from 1.4 bar running hot, to 0 pressure on the gauge.

That amount of water can be lost into a combustion chamber and evaporated in next to no time at all. Same with a PRV, only a few cups of water lost can significantly drop pressure as you can now imagine. The suggestions you've had to isolate the boiler with service valves and check there is a good one. Even doing as also suggested, topping up the system, don't run it at all and check for water in the combustion chamber will really narrow the problem down.

Thanks @Stigster I was expecting to find water gushing out of somewhere. I did not realise how little water you actually have to lose to reduce the pressure to zero. If the pressure holds like it is at the moment, I'm just going to wait until the oil boiler is properly serviced. Whatever was causing the pressure loss is gone for now and I don't want to jinx it by going poking around in the combustion chamber. I'll leave it to an expert. My only concern at the moment is, what impact will it have on my system running slightly above the recommended pressure. Thanks!

 

[Stigster]

The system will be fine running at that pressure. Everything there will be rated to take that and more. If it gets up to 3 bar your PRV will protect the system anyway.

 

[SJB060685]

@Brambles. We've never had any of our systems go up but then we installed correctly and know what we're doing. Do you mind showing us these pictures you mention? I curious to see how bad things got before fire valve kicked in.

 

[G M]

GM

The pressure within the primary flow system is rather like a balloon - it either leaks or it does not. But it will leak if the skin is penetrated. Heat protection is outside the primary flow skin. Moving / removing any form of refractory lining, plates or other protection should have no immediate impact on the pressure within the primary circuit.

The boiler needs to be set up in accordance with the manufacturer’s instructions. They (oil fired boilers) should not be configured on a trial and error basis. If the refractory protection on an oil fired boiler fails, in conjunction with the fire valve not responding quickly, the effects can be catastrophic. If you want photo's I’ll post them.

Be aware that most (if not all) UK Insurers subscribe to Athena Intelligence which quickly and effectively picks up forum and web chat (open and dark) et al conducted ahead of subsequent major insurance claims.

Thanks @Brambles I'm not sure what you mean by trial and error. It was installed by an experienced installer. Not by me.

I'm not sure why you're mentioning this. If my system suffered a catastrophic failure and water started leaking everywhere then surely it's reasonable to expect some assistance given that I'm paying them for it. I appreciate it is also reasonable to expect your system to be in working order, which is why I'm getting the boiler serviced as soon as possible.
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Finally I think I've found the problem! I was going into my garage this morning to get a few things and when I opened the door, the floor was wet. I heard a hissing noise coming from behind a cupboard and lo and behold; This:

As you can probably tell, this is an extremely old rad that I didn't even know existed. It was behind a whole load of stuff in the garage. I really have no idea how/why it's even still connected. We had a whole new heating system installed when we moved in just over 2 years ago. Would it be reasonable to expect these old rads to be disconnected?

I think putting the the extra pressure in the system has helped me to find this. There's quite a few things ruined in the garage with all the water damage but thankfully nothing too valuable. I've now ripped out this piece of junk and put stop ends on it. The first time I've ever done it, but seems straightforward enough. There's no more leaks at least.

I've topped up the system to 2 bar and sure enough, when I switched the heating back on, the pressure increased to almost 3 bar. It never increased at all during this whole debacle, so surely that's a good sign. I've brought the pressure down to around 2 bar whilst the heat is on, so expecting it to drop a little when the heat is off. So long as it drives the radiator in the utility room, I think the job is done.

I'm going to put some inhibitor back in the system via the towel rail provided it remains stable, then I'm going to get the boiler properly serviced. Not sure if I'll get it done in time for Christmas, but I am trying to find someone to do it.

Thanks again to everyone for your great help. I've learned a hell of a lot from you all. Fingers crossed this is a fix!

The culprit:

Removed (back):

Front

A taped pipe? WTF???

Stop ends on flow an return. Yes, I know you all could do a better job

 

[Stigster]

Wow! Wasn't expecting that to suddenly crop up. Amazing.