BIG OLD BOILER

[normspanners]

Hi guys,
just running an idea by ya,
my old faithful glowworm 100000btu 25yrs old and still perfect, stripped cleaned and serviced it today.
And it is running fine but I fired it up with the top off just to see how much heat passes the H/E--- WOW
so looked into condensing boilers but the reviews are mixed and the reliability is not good they recon 6-7 yrs and they are getting to the end of their lives etc etc apparently they have had 80,000 call out's in yorkshire this cold snap already. ( why Yorkshire was mentioned IDK?)
and unless you control the return flow accurately they cannot keep in the condensing window,
so the efficiency drops off to similar too the old units.
The general prognosis was with an older house if it is working dont change.


Now my idea was to mod the top of the boiler to include my own heat exchanger fins that pass through into the burner space and out of the top and to blow a fan over the fins to use this wasted heat and blow it into the kitchen

as you can see the wasted heat at the moment is my rod oven,
but you can see the top plate which is held by the thumb screws it would be simple to make a new one,
the top of the water heat exchanger segments is level with that through bolt so there would be plenty of space to slip fins through to pick up the heat when the boiler is running but also, when up to temp it shuts down but the heat is still passing out of the core and disappearing up the flue! It is like having a big rad outside.
my idea is to have the fins extending down into the boiler space then through the new plate up into the space you can see at the top and have a wide shallow fan at the bottom blowing over the fins, ducting the air and then turn the air at the top, back and out towards the camera into the kitchen,
when it is very cold we leave the front door off and it makes a big difference to the kitchen.
the boiler is behind a planked 'door' that just looks like the wall boards it would be easy to put avent in that door so the air can blow through it .
obviously the top would be solid ie sealed from the burner space.
The heat coming off the top would appear to be similar to a 2-3 KW electric blow heater!!
WDYT

 

[the snooper]

i was thinking something similar earlier but to do with gas fires, why is there no heat exchangers on the flu pipes for instance to blow warm air into your bedrooms it can be done, why let the heat simply flow out of the flu

 

[normspanners]

I did similar when I fitted an Eberspächer heater to a motor home and we ran the exhaust through another bigger pipe that acted as a H/E and was ducted back into the interior with a small fan and it acted as a silencer because the exhaust 'farted' quite loudly and there was significant heat coming out of it.

 

[the snooper]

its simple yet no one seems to do it, just been looking on net some people have made them for wood stoves and heating water, a mate of mine has a boiler similar in design to yours but much bigger, its a commercial boiler in a club and that's from 1972 and still working, it has a big old gas meter and the red needle is going for the speed record when it fires up

 

[Gareth J]

Lower flue temps equal higher efficiencies but get lower than so low and "things" start condensing out. Hence condensing boilers. There will be lots of vapours waiting to condense, water being the majority and one of the first but there'll be plenty of other nasty hydrocarbons as well as c02 dissolving in the water; carbonic acid?? The hotter the flue temp, the cleaner it will stay.

I would say go for your mod but make it reversible and control the fan thermostatically based on flue temp. I recon start the fan running at about 200C to start with and if, after a month or 3 the inside still looks clean, drop the kick in temp a bit.

Good luck and don't kill yourself/your family

 

[normspanners]

The top plate gets mighty hot, havnt run my temp probe on it but even when the burner has stopped and waited a while it is impossible to hold your hand on it. The heat loss must be fan-ominal but with my mod it might be FAN-minimal??


I few words on condensing boilers
https://gtms1312.wordpress.com/2013/03/22/the-truth-behind-condensing-boilers/

 

[cumbriasteve]

I was chatting to the boiler fella a few weeks ago, apparently when the snow and ice arrive 75% of their call outs are to frozen drain lines, usually caused by bad installation routes and pipe diameter.

He also commented a hell of a lot of condensing boilers are not working correctly because they only work well if heating large volumes of water and most houses should have larger radiators than they initially got installed.

The above may be a load of rubbish but he seemed a decent guy and not prone to bull ********

 

[RBDIVE]

Norm,
You might already know, but in case.
These boilers are not room sealed and have open combustion chamber into the room, and on this boiler you can get the flames shoot out the bottom when there is not enough draw on the flu (out the removable bottom metal black cover)
hope you improve your boiler

 

[MrFluffy]

The reason its not done is because the flue needs a strong draw to take the spent gases out. My experience is with wood burning fires, but the principles are the same.
A chimney stack is a thermal device, you feed it very hot air at the bottom and the heat rises up the flue to the outside sucking the spent gases out with it stopping same said gases from ending up in your room instead and asphixiating you. If you cool the gases you reduce this action and can end up with carbon monoxide and worse in the room as a result.
There are systems around with roof mounted fans at the top of the chimney stack to improve the draw so you can reduce temperatures into the exhaust gas, but they are prone to failure long term given the environment they work in.

 

[normspanners]

The above may be a load of rubbish but he seemed a decent guy and not prone to bull ********

No that seems to be correct from my finding too and that is another---- NO from me---- because I have fitted zone vales to allow just the kitchen hot water and bathroom to be on, when needed so the return flow will be well hot.

 

[normspanners]

Norm,
You might already know, but in case.
These boilers are not room sealed and have open combustion chamber into the room, and on this boiler you can get the flames shoot out the bottom when there is not enough draw on the flu (out the removable bottom metal black cover)
hope you improve your boiler

yes Thanks I was aware of that.

 

[penfold]

The reason its not done is because the flue needs a strong draw to take the spent gases out. My experience is with wood burning fires, but the principles are the same.
A chimney stack is a thermal device, you feed it very hot air at the bottom and the heat rises up the flue to the outside sucking the spent gases out with it stopping same said gases from ending up in your room instead and asphixiating you. If you cool the gases you reduce this action and can end up with carbon monoxide and worse in the room as a result.
There are systems around with roof mounted fans at the top of the chimney stack to improve the draw so you can reduce temperatures into the exhaust gas, but they are prone to failure long term given the environment they work in.

The boiler he's showing is a forced draft furnace, as most domestic boilers are; adding a few fins either side of the top plate won't make a blind bit of difference, although they'll need cleaning and it'll be fiddly and messy.

 

[normspanners]

Norm,
You might already know, but in case.
These boilers are not room sealed and have open combustion chamber into the room, and on this boiler you can get the flames shoot out the bottom when there is not enough draw on the flu (out the removable bottom metal black cover)
hope you improve your boiler

Cheers for this, but just to add.
When i first fitted the boiler I let the plumber do the gas connection and he wanted a very long piece of 15mm i went and bought the long length and he threw it in the trench with open ends when the boiler was commissioned it worked fine no leaks etc then after several mths the gas bill in the summer was virtually the same as the winter, the sand had made its way into the gas valve and was escaping into the boiler two valves where fitted by glowworm and all ended up the same eventually cost me a fortune in gas. the way I found the problem was as I came through the back door the boiler lit, this happen a few times and then I looked at the settings and it was off.
So a new valve was fitted under warranty, but after the second valve I became suspicious, and stripped the first valve, left by the engineer, he said, have you got a scrap pile ? ---OH YES---,
the valve seat etc was full of sand, I cleaned it out refitted and perfect .
Annoying coz in the blurb it said purge the gas line before final connection, plumber man said oh I dont bother never had a problem.


Now the point is in all that time nearly 2.5 yrs never once did we smell any gas have any blow backs etc etc all that gas and with it about a £1500 went naturally up the flue with no problems at all, so the 'suck' is fine, it pulls, even with the boiler stone cold, I tested it with a smoke bomb .
so dont think I will have any problems with a cold draw.

 

[Kent]

I was chatting to the boiler fella a few weeks ago, apparently when the snow and ice arrive 75% of their call outs are to frozen drain lines, usually caused by bad installation routes and pipe diameter.

He also commented a hell of a lot of condensing boilers are not working correctly because they only work well if heating large volumes of water and most houses should have larger radiators than they initially got installed.

The above may be a load of rubbish but he seemed a decent guy and not prone to bull ********

What he is referring to is the stop-start firing of not having enough work to do, its like having a V12 milkfloat that's used on a big council estate or the likes (stop, go,stop,go,stop,go.....). Boilers must match what is required of them closely, however some installers think "better to go bigger, just in case" bad plan just like the milk float.

My boiler and all its condensation drain pipe is outside, all the heating engineers who see it make comment on it not having enough fall! What they don't get is the trace heating that is fitted along its length. Its gets seriously cold here and I can tell you fitting this stuff is a must but it must be compatible with plastic pipe if that's what you might have like I do

 

[pedrobedro]

Our boiler is an old Glow Worm 45-60 and it's older than yours I think. It was already fitted when we moved in 30 years ago and all I've done to it apart from services is fit an ebay gas valve (which are getting rare now) last year. A friend of ours has had 2 condensing boilers fitted during this time, can't get parts to repair them after about 5 years according to the "heating engineer". Whatever you save on bills you spend on new installs so unless you are in a position where the boiler is dead completely it's not clear cut as to whether to replace or repair.

 

[Rig Pig]

I have a reasonably modern oil combi Wooster, it's very efficient BUT it isn't the most reliable and every part is a fortune.

 

[CompoSimmonite]

If you buy from Scotland you can still easily get traditional balanced flue boilers ! The rules are the same as the rest of Britain but the Scottish attitude is if London wants to pay for the boiler then they will have condensing but if they have to pay themselves then they will make their own decision on what to fit.
Balanced flue boilers are also available in England but harder to find.

 

[normspanners]

Balanced flue boilers are also available in England but harder to find.

mine isnt balanced flue, if it was the bathroom would very toasty !!
mine is conventional chimney flue, well I say conventional I think balanced are now the norm. But not for this Norm.
I am old school and like my gasses to go up up and away.

It really annoys me when people make decisions-------for me------ that I have (HUM) to accept when half the time the people that make the decisions have not a clue what they are talking about.
My gas bill is not out of the way expensive and by all accounts fitting a condensing boiler will not improve it vastly, so what is the point apart from getting me to spend MORE money which can have even more tax on it.

over the 25 yrs years the cost of my boiler works out to have cost me 31p a week----- i think I can handle that!!

 

[octo0072000]

The top plate gets mighty hot, havnt run my temp probe on it but even when the burner has stopped and waited a while it is impossible to hold your hand on it. The heat loss must be fan-ominal but with my mod it might be FAN-minimal??


I few words on condensing boilers
https://gtms1312.wordpress.com/2013/03/22/the-truth-behind-condensing-boilers/

dont mess with the top plate
just make up angled box to fit on top of it 10mm plate to the boiler top with a fan in it will hold the heat and no messing with the boiler

 

[hunter27]

Don't do it

No longer in this job but
Your boiler is a conventionally flued (and not fan assisted)
It relies on the heat leaving the heat exchanger to help make the flue start and continue to work (especially on cold still days) and the fumes are just as happy to come out from the Down draught divertor behind the boiler than go up the flue.
We have had boilers with borderline flues pass a flue tests one day and fail the next. when they do fail they have to be capped off until work is done to correct the problem and they pass.
Fortunately most boilers these days are room sealed so are a lot safer.
We were not allowed to alter any appliances from the manufacturers original spec.
If you did this and a Gas safe engineer saw it he would have to turn it off immediately and cap it. If you didn't allow this it is likely that your gas supplier would turn up and cut off your pipe in the road, or the engineer would end up partly responsible for anything that happened later. If we left anything like that I suspect we would have been suspended even if there was no incident.
Unfortunately sooner or later every one will have to replace the old boilers. Condensing boilers are a lot more efficient than old conventionally flued cast iron boilers even when not in condensing mode, better makes of boiler are usually better for obtaining parts when they get older,condensate pipes should be run inside wherever possible. I think decent boilers should last 12-15 or more years if your lucky.
There is a lot of rubbish for sale that probably will not last that long though.