Old back boiler safe?

[TimJM]

Hi,

We moved into our house last year and a few weeks before Christmas I had the gas fire removed (one of those coal effect jobs) and have been burning coal and wood in the open fire. I became aware of the potential safety issues with an old back boiler this week and it made me unsure of how safe mine is. The thing is though the survey, the chimney sweep nor the gas safe guy who removed my gas fire mentioned any potential safety issues with an old back boiler.

It seems to be a cast iron "FIREMASTER - HIGH OUTPUT BOILER" (that is what the plate on the front reads). The house was build in 1930 and I believe the fire is original. I have a combi boiler in the kitchen for hot water and the rads but I think that was done 20-30 years ago.

The problem I have in finding out about a safety issue is that I can't seem to access anything around the back boiler plates. The cast iron just seems to run flush with the walls and turns into the chimney. No pipes and no access. Here are some images:

It is hard to see what is going on but the sides and back of my open fire seem to be cast iron. The plate I have removed has an air channel that runs from the bottom of the grate behind that plate and out the top (just above the plate). Behind the plate about two-three inches back it is just cast iron again. No openings, no levers, no panels (other than the iron plate with the lettering on).

There was a gas fire installed which had been in use for the last 15 years when we bought the house. We have been burning coal and wood for the last 8 weeks sometimes upto 14 hours a day.

My gut feeling is that if I was going to have a pressure issue leading to an explosion it would have happened by now but also I can't stop having this niggling doubt.

My problem is I can't see other than taking bricks out of walls how I can check what is going on. As I said there are no pipes or anything visible. The plate at the back and the next layer of cast iron are at an angle leaning forward. Then it slopes back into the chimney. The cast iron runs flush onto the chimney walls around the sides and the top.

Is it going to be a case of starting to knock bricks out to try and find what has been done?

Any help would be gratefully received. I know nothing about old open fires.

Tim.



Tim.

 

[compheat]

This type of boiler used to supply the cylinder, chances are its still behind the cast iron front and will be made of copper.
The pipework could go up inside the chimney breast or at the side of the breast, easiest thing to do is drill a small hole in it and let any water out.

 

[TimJM]

Thanks for the quick reply.

So drill a small hole through the cast iron behind the plate and presumably into something else (probably copper). I did think about drilling a small hole as that would make the back boiler safe even if it has not been correctly disconnected.

The only thing stopping me is the thought of flooding the lounge. In my loft I have four header tanks, one must be for the radiators as the water warms up once the radiators are on, one is a great big steel box that seems to be empty and the other two are large plastic boxes with lids on. If the back boiler is still connected I guess it will empty the header tank into my lounge until it runs out (and I turn off the main stopcock).

I suppose if I light a fire, leave it to burn for a few hours and then go into the loft to see if any of the other header tanks are heating up, this will tell me if it is still connected but redundant.

If I find no change in the loft then will drilling a small hole through the cast iron and into anything I feel behind it should make it safe? Do I need to do anything else?

Thanks,

Tim.

 

[algas]

I would think if you have been having a fire lit for up to 14hrs per day for last 8 weeks it should be safe to say there is no water left in the unit.

 

[TimJM]

I would think if you have been having a fire lit for up to 14hrs per day for last 8 weeks it should be safe to say there is no water left in the unit.

That was my thoughts, we have two young children and access to cheap logs. To save some money we tend to have the heating off most the day as everyone is in the lounge and just keep the open fire burning all day. The fire is usually lit around 9ish and I tend to let it die down about 11pm (the lounge stays very warm). My main concern was that the system could still be fed somehow with water. I have heard that this is rare but the back boiler is safe if it still has water running through it. It is only unsafe if it has standing water in it that can't escape.

Also, how hot should the walls be around the chimney breast? If you put your hand on the wall in the hall (the back of the lounge chimney breast) it is still warm in the morning. Is this normal or could this be where the back boiler is and it is holding onto the heat overnight?

Thinking about drilling again, if the copper boiler is behind the cast iron and I drill trough it - wont the water (if it has any) just leak out between the copper boiler and the cast iron front? I won't be able to catch the water if this is the case. I could just have a load of towels ready as I guess the water will have to run out the bottom of the chimney breast somewhere....that or just slowly fill up the chimney.

Tim.

 

[algas]

Or Pi## out black sludge all over your lounge carpet

 

[GasSafeTony]

http://www.hse.gov.uk/services/localgovernment/boilers.htm