v8kid
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| posted on 13/2/11 at 02:37 PM |
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Old gas boiler
I'm looking for an old gas boiler to convert to LPG to heat my new project - a hot tub made from an IBC. Guess I'm anticipating a good
Summer 
Anything going in Central Scotland/Borders?
Cheers
David
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
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v8kid
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| posted on 17/2/11 at 12:43 PM |
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Nobody? I'm going to Oldham on Monday to pick up a gearbox anyone in that area got an old non condensing gas boiler I could convert to LPG?
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
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DarrenW
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| posted on 17/2/11 at 05:24 PM |
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My dear fellow, why not go eco and design it around a log burner? An old gas bottle with some coils of pipe and a small pump should get water rather
jolly nice. A guy i know in Sweden made such a thing on a trailor. Being powered by logs meant he could take it to his mates' houses etc. It
took approx 3 hours to heat up, just enough time to enjoy a few beers and the bbq.
IBC is a great idea. Would be easy to clad so it looks pretty, fairly easy to fit seats inside. Good plan.
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v8kid
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| posted on 17/2/11 at 06:52 PM |
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Thought about log burner but cost was a bit high as was lack of control - I can imagine cooking like a lobster and coming out smoked! Also logs are
not cheap, although I live in the country petrol, and spares for chainsaw plus diesel to transport them makes the cost roughly that of gas.
Also reusing an otherwise disposed of boiler makes sense. The efficiency will be higher than in the original use due to the low flow and return
temps
Would be fun though
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
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owelly
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| posted on 17/2/11 at 10:57 PM |
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I have a workmate who has just bought a new gas boiler because the pressure vessel on the side of his old one popped due to the outlet freezing up.
New pressure vessels can be bought new for £35-£45. Interested? He, and the boiler, are in Whitby but I'll happily arrange uplift for you.
http://www.ppcmag.co.uk
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v8kid
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| posted on 18/2/11 at 09:05 AM |
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Thanks for the help chaps its much appreciated. I think I've already sourced one already converted for £25 - apparantly LPG non condensing
boilers are in low demand due to current building regs. Due to the low flow and return temps in my application any boiler will condense so I get low
cost and High(ish) efficiency. As a bonus the output should be slightly higher too!
cheers
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
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MkIndy7
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| posted on 18/2/11 at 10:42 AM |
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I hope it all works for you but just a warning about the low return temps etc and the water condensing..
A condensing boiler is designed with the burner head at the top of the boiler and effectiely fires downwards with the flue gasses pulled by a fan out
of the bottom of the boiler so any condensation from the heat exchanger or what runs back down the flue collects in the bottom and is drained via the
condensate trap. This condensate is verry corrosive and real nasty stuff.
In a non condensing boiler the burner rails are at the bottom and the hot gasses rise up through the heat exchanger, when it first lights off these
gases and the heat exchanger do condensate but only for a very short period after which point when everything is hot enough they are evapourated off.
If the boiler is running in this state for a long time, which it souds like yours will, there will be conensate constantly dripping onto the burner
rails causing a bad flame and corrosion. Swimming pool boilers were either specially constructed for the task or you used a regular boiler and a heat
exchanger so the higher boiler temperature could be maintained.
Also the boiler thermostat alone probably wouldn't register below 50 DegC
Wouldnt want to be a fly in the ointment but there is quite alot to be considered as its not always as simple as it seems.
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BenB
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| posted on 18/2/11 at 11:29 AM |
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Why are condensates so nasty? I know they are just not sure why? Is it the old COx, SOx and NOx (from the fumes) making various acids in combination
with water?
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MkIndy7
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| posted on 18/2/11 at 11:44 AM |
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Yup I think its all those nasties etc.. old non condensing boiler flues used to run at over 100 DegC so they will have been carried off up out of the
flue, but now flue temps are down to 60Deg or less they are still there hanging around.
Just tried looking up exactly what is so nasty in them, but the water authoritys are starting to be concerned:
A condensing boiler from an average household will produce approximately 800 litres of acid per year at pH4 level.
s more condensing boilers are installed, conservative estimates suggest that in two years time, 50 million litres of acid at pH4 could be added to UK
drains each week.
Aparently there worried about it attacking the lime mortor in Victorian sewers aswell!
I've seen it eat through a 3/4" iron fitting in less than a year that some numpty had used.
Another of those crazy ideas that were rushed in by the government at the time (like the smoking ban) without any great thought. When it first came in
there was only about 3 manufacturers that made a condensing burner/boiler so everybody bought or liscenced that burner, was quite funny really loads
of different cases and colours n sizes etc and when you took the cover off they were pretty much identical underneath!.
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v8kid
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| posted on 18/2/11 at 01:47 PM |
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Thanks for pointing that out I had clean forgotten about acid condensate. The condensate from condensing boilers has to be treated with alkali before
it is fed into a drain and it is a standard plumbing item now - at least it is here and building control check for it.
I will just be angling the boiler slightly so the condensate drips away from the burner. I don't think I will be having enough hot tubs a year
to make corrosion a problem and at £25 a throw for replacement boilers am not too bothered although if I can avoid the hastle simply will do so.
Cheers and ta.
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
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MkIndy7
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| posted on 20/2/11 at 05:51 PM |
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Just had another thought if your looking to heat the hot tup as cheep as possible, how about a solar water heater.
I'm pretty sure theres been some good threads on here about them but this is the best I can find with a quick search:
http://www.locostbuilders.co.uk/viewthread.php?tid=128087&page=1
This can be left out all the time and then use the LPG boiler idea as a boost
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v8kid
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| posted on 20/2/11 at 07:45 PM |
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Well I do live in Scotland but last summer WAS sunny. It would reduce warm up time and the more I think about it that's a pure dead brill
idea.
Going away to do some sums.
You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a
chainsaw
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