Condensation forming inside boiler

Sanguine Fan

I have an external oil-burning boiler which is at least 10 years old. I have it serviced each year and it is still functioning well. (See attached photo)

Recently, during the dry weather, I noticed a wet patch on the ground at the base of the unit. There was no smell or taste of oil so I figured there was a water leak.

I turned on the system and removed the side panel (facing right in the photo) where the burner and controls are situated. Everything was dry - no obvious leaks. Then I took off the top panel and noticed quite a lot of condensation on the underside of the panel. This seemed to be seeping down through the unit and out onto the ground.

What could be causing condensation to form like this and how can I stop it?

Many thanks.

Wearb

If you are SURE its not oil (oil can run long distances between the copper and plastic covering on the fuel pipe) then it is an awful lot of water. There may be a leak of water coming out of the pressure relief valve or vent. Identify where those parts are and have a good look around it when it has been running for a while. Have you a sealed or open vented system?

Wearb

I would rub a dry hand around that joiner on the fuel pipe and at the burner and and oil pump.

Sanguine Fan

Wearb wrote: »

If you are SURE its not oil (oil can run long distances between the copper and plastic covering on the fuel pipe) then it is an awful lot of water. There may be a leak of water coming out of the pressure relief valve or vent. Identify where those parts are and have a good look around it when it has been running for a while. Have you a sealed or open vented system?

You are right about the quantity of water being too much for condensation to be the cause. And it is definitely water rather than kerosene. There are no valve leaks. Everything is dry behind the right panel where all the controls are.

The problem is that the panels at the front and left side and riveted onto the frame so they can't be easily removed to see what is going on in the area where the water appears to be leaking from.

I had a plumber look at it this morning and he thinks that metal corrosion is the culprit and that I need a new boiler. Not good news coming up to Christmas!

It's an open system by the way.

Wearb

Sanguine Fan wrote: »

You are right about the quantity of water being too much for condensation to be the cause. And it is definitely water rather than kerosene. There are no valve leaks. Everything is dry behind the right panel where all the controls are.

The problem is that the panels at the front and left side and riveted onto the frame so they can't be easily removed to see what is going on in the area where the water appears to be leaking from.

I had a plumber look at it this morning and he thinks that metal corrosion is the culprit and that I need a new boiler. Not good news coming up to Christmas!

It's an open system by the way.

"he thinks that metal corrosion is the culprit" That is not enough information to be going on to ask someone to replace a boiler. He has to take off those panels and find where it is leaking. Also unless the whole boiler has rotted out, I have seem them welded with great success.

Sanguine Fan

Wearb wrote: »

That is not enough information to be going on to ask someone to replace a boiler.

I agree but here's my dilemma. If I disassemble the whole casing to try to find out where the leak is, I may not be able to put it back together. I am definitely not an expert and I'd hate to screw up the system in the middle of winter.

There is definitely a leak and it is probably the result of corrosion. I can't imagine what else it could be. If I were to get an expert to take it apart and it turns out that it can be fixed, then I may buy some more time on the boiler, and save a couple of grand.

But it's an old boiler anyway. We're living here 10 years and it came with the house. It did not look new at the time so it could be here 15 years or even longer. That must mean it is not very efficient, leak or no leak.

Ideally I'd like to nurse it through the winter and then decide what to do when it gets warmer. I suspect it has been leaking for a long time but I did not notice because the area is sheltered and the ground is usually wet. So maybe I'll get another six months out of it?

Billy Bunting

2 philips screws front and back will remove the top, 2 screws at the bottom of the rear panel will remove the back, you will then clearly be able to remove the internal insulation and see exactly what is happening, these type of leaks are more likely to be AAV or PRV and easy repairable.

Did your "Plumber" bother to remove the above before righting off the boiler ?

Sanguine Fan

Billy Bunting wrote: »

2 philips screws front and back will remove the top, 2 screws at the bottom of the rear panel will remove the back, you will then clearly be able to remove the internal insulation and see exactly what is happening, these type of leaks are more likely to be AAV or PRV and easy repairable.

Did your "Plumber" bother to remove the above before righting off the boiler ?

I wish it was that easy.

My plumber (why quotation marks?) removed the top and rear panels. Everything looked fine and dry. In fact there were two live spiders living in the space between the outer and inner back panels.

Yet water continues to seep out. The boiler is not level so it seems to be coming from the rear left corner, but that's probably only gravity at work.

Short of taking a sledge hammer to it, which is very tempting at the moment, I'm not sure how else to find out what's happening. At least it's working so I'll try to keep it going until the summer.

Billy Bunting

Sanguine Fan wrote: »

I wish it was that easy.
My plumber (why quotation marks?) removed the top and rear panels.

The problem is that the panels at the front and left side and riveted onto the frame so they can't be easily removed to see what is going on in the area where the water appears to be leaking from.

You said that only the front panel (right)was removed by the plumber/you, if that was the case and he wrote off the boiler on the strength of that then he was no "Plumber".
You say the rear panel (left, where the leak is)could not be removed has it was "riveted on", not so, that panel has 2 screws, even if riveted could he not remove them ??
Unless you get full access to the boiler you wont get to the problem which could be simple. Perhaps a few pics with the case off would help us help you.

Sanguine Fan

Billy Bunting wrote: »

Unless you get full access to the boiler you wont get to the problem which could be simple. Perhaps a few pics with the case off would help us help you.

The best I can do is attach my original photo with some additional notes.

When I noticed the patch I removed just the right-side door and had a look around. Everything looked fine - no leaks.

Next day my plumber removed the door, the top panel and the rear panel, and spent an hour examining the interior. Again everything looked fine.

I would not be happy about breaking the rivets without someone on hand who could put everything back together again. I don't know who made the boiler but presumably they used rivets instead of screws because these panels do not need to be removed for a service.

The boiler is functioning so far and I need it to keep going. Maybe if it was summer I'd risk it.

Wearb

Sanguine Fan wrote: »

The best I can do is attach my original photo with some additional notes.

When I noticed the patch I removed just the right-side door and had a look around. Everything looked fine - no leaks.

Next day my plumber removed the door, the top panel and the rear panel, and spent an hour examining the interior. Again everything looked fine.

I would not be happy about breaking the rivets without someone on hand who could put everything back together again. I don't know who made the boiler but presumably they used rivets instead of screws because these panels do not need to be removed for a service.

The boiler is functioning so far and I need it to keep going. Maybe if it was summer I'd risk it.

Your plumber should have stripped this boiler down to the bare metal of the boiler itself. Your are right about those rivets and service, but we are far from talking about a service at this stage. Have all of the covers removed and all the insulation removed. Only then can you really see what is happening. That is presuming you have managed to get eyes on pressure relief valve and other fittings already. Don't be too quick to write off that boiler.