HOJ
Established Member
Maybe one for @Bingy man I have a job to make good around this gas boiler and flue, is there a rule as to how close I can get with a piece of Oak veneered MDF to the flue pipe, It wont be permanently fixed, just clipped on.
Gap round gas boiler flue
- Thread starter HOJ
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Assuming that’s a condensing boiler then there is little or no heat emitted from the flue , I’ve seen plenty that simply sit on top of the boiler so nothing in my experience to worry about .a 25 mm clearance should satisfy most manufacturers but if your customer has the installation instructions then it will likely be under servicing or access .. as long as it’s not a fixed structure then it won’t be classed as a flue in void situation..
HOJ
Established Member
Thanks @Bingy man, appreciate your reply.
HOJ
Established Member
Nothing too exiting, but job done, not exactly a piece of fine woodworking, but it meets and exceeds the customer expectations, as they say...
Perfect 
Having worked with various aspects of airflow in metrology it always amazes me why people use such a tight bend for the flue, it is really not the best for airflow but I can see that boiler location has a major influence so not always possible to avoid. A nice straight run out of the boiler before a bend is much better for flow, I ran my flue straight up into the loftspace and then out of the apex end wall but it is a bungalow and I ended up with a nice short clean flue path.
The old floor and wall mounted boilers had a 2 ft rise above the d d d before any bend , not every installation was compliant and those that weren’t always had issues. When fan flued boilers were developed it was deemed not necessary and as these have evolved into the condensing boilers of today they have even stronger fans and can push the p o c, even further away even when they start of with a 90 deg elbow. An elbow is equivalent to between 1/2 and 1 meter of flue pipe so this is calculated as part of the maximum flue length.
Yes these bends are making the fans work harder to maintain the Dp so having that straight section must help. The problem today I think is that once upon a time a boiler was fitted and expected to last for years but now these combi's are almost throwaway, remember when putting a boiler on the wall was a two man job !
Agreed , and as for 2 men to fit hang the boiler there were several that took 2 men for a heat exchanger replacement ( cast iron ) where as nowadays it’s almost a 1 handed operation. Then there was the floor standing jobs that came on a pallet that 2 or 3 men dragged and hauled it into the house .. nowadays manufacturers only have to supply parts for 10 years so potentially you could be changing it again sooner than you think . Oldest boiler I ever worked on was around 46 years old - crane cavalier- a solid bit of kit that looked like it had just left the factory complete with a wind up mechanical timer 
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