Alternative to Monodraught balanced vertical flue

[JEF]

First of all hello to all here.

First post, so here goes...........

I found Monodraught after a bit of Googling, and their balanced vertical flue system seems to be the perfect solution to my "plant room" problem.

[DLMURL="http://www.monodraught.com/other-products/vbf/index.php"]Monodraught Ltd - Vertical balance Flues[/DLMURL]

Unfortunately they will not quote as the boiler is less than 70kW
(I have no idea why, as their flyer states 30kW to 6MW).

The problem:

The location of the boiler room on the ground floor does not have access to external ventilation and is approx 3M x 3M x 3.2M high.

The house is currently under reconstruction and is semi underground, as it is built into a slope.
The property is detached with a pitched roof and is not sheltered by taller buildings,

It will house a Janfire duoflamePE50. The maximum output is 46kw, but it is set to 30kw on delivery.

The flue diameter is 150mm with a length of 12M to the ridge with 2 off 60 degree bends. There will be a draught regulator included in the flue.

One problem that I can see is that the floor joists of the first and second floor are 150 x150mm wooden beams at 450mm centres, only leaving a gap of 300mm for the balanced flue to pass.

Any advice will be greatly appreciated.

Best regards

James

 

[stevetheplumber]

you would need to get this designed by a mechanical services engineer but you can make a sealed compartment into a balanced compartment using ductwork to supply air
boiler doesnt mean anything to me im talking about gas but possibly similar for oil lpg would be illegal below groun
can you not use a roomsealed fanflued appliance

 

[JEF]

Thank you Steve for your reply.

Yes that is basically what the Monodraught does, create a balanced compartment with a co-axial flue. The clever bit I guess is the terminal and the sizing of low and high level vents, which I assume would be required.

The boiler is log and pellet fired http://www.framtidsenergi.se/visa_produkt.asp?id=220&t=Janfire+Duoflame〈=sv (Sorry in Swedish) as we have no gas here.

For some reason wood burning boilers don't seem to use balanced flues, though IMHO it is a better system.

Best regards
James

 

[JEF]

The boiler is a dual burner version of this [DLMURL]http://www.janfire.com/eng/images/docs/janfire_uk_ed1.pdf[/DLMURL]
(5.2Mb English)

Regards
James

 

[kotpat1]

Jef

The Janifre Duoflame must be installed with a inline chimney fax. and is nota 150mm flue and should be a 175mm dia.
Can you confirm your area locationa nd your installer

I have been a user of the janfire for three years and may be able to assist you.

the syatem should have independent pumps and control to all systems
ie radiator, under floor and domestic hot water and solar.

me live local to aberdeenshire

 

[Reg Man]

Have you tried contacting HETAS? They are the solid fuel registration scheme provider. If they can't give specific advice, they are sure to point you in the right direction. I have not heard of balanced flued compartment being used for solid fuel. Its mainly a gas industry thing.

 

[kotpat1]

hi

if the boiler flue is installed correctly with the in line fan, then the flue system will be self balancing and the distance and bends in teh flue will have no effect,

if the flue has been installed at 150mm dia and not 175mm dia and the fan has not been installed, complain to the local planning department who will take action against the boiler installer.

The boiler supplier installer should have sorted all of this out for you.

cheers

 

[JEF]

Hi kotpat1

Is the 175mm flue and in-line fan a UK regs thing?
Janfire themselves quoted 150mm 0.15 mbar under-pressure with draught regulator?
Reading up on flue sizes for wood burners this does seem a bit on the small size.

This could be due to the location (Spain).

I'm currently trying to sort out a system that I believe will work, and be safe, before proceeding in engaging a heating contractor. The reason for this is it depends on the chimney type used i.e. masonry (lined), pre-fabricated or double walled.

Thank you for your offer to help, out of interest which model of Janfire boiler do you have?
Do you run on logs as well as pellets?


Reg Man

The idea of a balanced flue was first suggested by a Spanish heating salesman. It sounded like a logical way to go and indeed Schiedel and Tona both have a product for just this.
I am, however completely mystified as to how they conform to supply air cross sectional area unless they are intended for very low powered boilers.

 

[Reg Man]

I am not sure what the safety implications are for solid fuel balanced flue compartment. The Gas industry compartment doors are interlocked with the boilers to shut them down if you enter the plant room. Obviously that is not posssisble with solid fuel.

 

[kotpat1]

hi send me your email address as the janfire docs translated from german and also a english copy state flue dia 175min

I have a 23 kw pellet boiler and we are awaiting its removal as being to small for our home and the ash scrapper continually jammes and the grea box is only plastic gears.

cheers

 

[verdigrey]

I cant be of much help except when I was at an OFTEC ( oil ) training session one of the guys said that Monodraught flues dont allways work , whatever the manufacturers say .

 

[JEF]

Reg Man
I didn't know about the interlocked door requirement.
I wonder how Schiedel get away with it? Maybe the system is only available in Southern Ireland and the continent?
I presume that the problem is that the room could become at negative pressure with respect to the flue resulting in CO leakage? If this is the case what is the difference between a sealed room with the door open and a conventional boiler room with a big hole in the wall which must be effected by wind direction?

kotpat1
Yes please I will pm you after this reply.
Are Janfire sorting this out for you?

verdigrey
Do you have any further information on this ?
Is it a Monodraught specific problem, or balanced / sealed rooms in general.

Best regards
James

 

[verdigrey]

It was in a supermarket which had a flat roof i think , but that is all they said , not much help . In the event of a power cut the whole system needs to be safe of course .

 

[Reg Man]

The principle of balanced flue compartments is the same as a domestic balanced flue boiler. It relies on the air intake and flue outlet to be located in the same pressure zones. Additionaly it requires the case/compartment to be totally sealed. Therefore the door of the balanced flued compartment must be practicably air tight. We have all seen what happens to the flame picture on a natural draft balanced flue boiler if you light it with the case off. So extra measure of interlocks is required on the door of the compartment. Fine for natural gas and LPG because you can turn it off: but solid fuel its a problem. The requirements should not be different for EU countries, as we are all meant to be working from the same standards? The only flexibility for LPG, is the inclusion of small dump holes in the base of the compartment to ensure any gas ecape can be released from the compartment. Very specialist design criteria, must be left to the experts.

 

[JEF]

kotpat1
Thank you for the information.
Due to the size of the firebox in the Duo flame, only 160L, IIRC that would give a single load of logs a yield of only 155kwh.
As I get logs for free and this would suggest a reload interval of less than 3.5 Hours, therefore not an economic option.

verdigrey

The boilers I'm now looking at have a heat exchanger to cool the boiler, by mains water, in the event of an extended power failure.

Best regards
James

 

[kotpat1]

hi the duoflame is not a log boiler only a pellet boiler, henc the slam 160 litre area

best of luck

 

[JEF]

Reg Man
Yes, I agree this is a specialist subject, but I like to understand if something is possible, before I ask a few questions.

Sorry to sound xenophobic, but there a lot of people here who do not
know what they are doing (I'm not referring to this forum) , and will
not ask if they don't know. This is why I'm exploring the idea here.

Thank you for your help so far.

James

 

[JEF]

When I spoke to Janfire in 2009 in Spain about the Varioflame which is a log and pellet boiler, they informed me that a higher output boiler, that met my requirements was due March 2010.
The quote I received was for the Duoflame.
It's a shame as the Varioflame looked well made good value for money, just is not powerful enough for the property and the Duoflame appears to be pellet only.
James

 

[Reg Man]

Thats Fab. None of us know everything, including me and its good to share what knowledge we have. It's extremely frustrating when we come across situations we don't know enough about, so the forum is a great leveler to hear other proffesionals views. I Find one of the biggest obsticles is the expense to access codes of practice (BS/EU standards) We have the regulation and enforcement bodies on our backs when things go wrong, and we can't access EU/BS docs with out huge expence time and effort to interpret what they require. I call it British Standard Speak.

Steve

 

[JEF]

Anyone know why hole in the wall is regarded as being safer than a sealed room with an open door?

My thoughts for discussion (If anyone is interested)!.

As drawing air from a room, with suitable vent for combustion air, is legal and safe, why would it not be safe to replace the vent with a tube?

I can see that, with a Monodraught system with a short flue stack, there could be insufficient draw on the boiler with the room being unsealed i.e. by opening a door.
With a full stack I cant see why it would be a problem with an appliance with an exhaust fan. If, however, the boiler was of a natural draught type, then some fluctuation of exhaust gas flow would occur until the system stabilised.

Please comment.

James