Hi... I'm replacing a kitchen. I have an old 20.7kw open flue gas boiler wall mounted next to exterior wall, which I intend to put a kitchen unit door infront of and a kitchen unit to the side (but totally open above and below). 1)- What air gap do I need between the chipboard and boiler..7.5 cm? 2)- What do I need to do about ventilation.? a gas-plumber told me I would need a vent above (4.5cm^2 per kw) and below (7.5cm^2 per kw)as its enclosed... but as its open above and below my understanding is that it is only room enclosed so I don't need to add extra direct external ventilation.. 3)- The kitchen has a ~20cmx20cm air vent on outside.. but the installer (house builder) seems to have bodged it... its not lined, and theres a bodge job of a deflector (some wood with holes drilled in..!) its also in the way of where the unit front will go... I had added some 11x5.4m ducting in wall to move inside inlate to above boiler.. but was told this reduced free air.. so I'll probably need to move it/ rework it, what do I need? 4) The plumber recommended changing the boiler for new condensing.. though ( my ~20year old) I've had no problems with mine ... I heard from old streams that new condensing boilers were less reliable (much more complex).. and shorter lifespans is this still true? 5) After! moving the gas supply to boiler (about 1m) in 15mm copper, I was told that often new ones need 22mm piping. as this would run from beneath worktop to boiler above is it worth getting this reworked again in 22mm...in case I need to replace boiler at later date? Any advice on any of these points would be greatfully received.. unfortunately relevant standards are reasonably expensive to download. Clive
Must have Make and Model number (G.C.Number if you have it) to check specific requirements for any given boiler.
Thanks very much for your response.. I'll look up that information. offhand on the front it says stelrad IdealW. but I can't see any mentions in google.
OK thanks.. contacted stelrad group directly For this boiler free air room 34inches^2=165cm^2 free air direct from outside 17inches^2=83cm^2 min Gap between appliance and combustale material 75mm As open at top and bottom should amply meet air-room requirement.. I assume therefor I just need to ensure the vent from kitchen to outside meets 17inches^2=83cm^2 requirement
CMF,As you are having a new kitchen i would recommend a new boiler definately.Having not seen your boiler & it being wall mounted open flue, i doubt it as a minimum vertical straight 600mm flue rise off the boiler.Which means your installation is not up to current standards,also regarding the ventilation you need to consider the extractor fan which you probably will have.The boiler alone requires a permanant external ventilation -just to quote the regs where an open flued appliance has an input rating in excess of 7 kw the room or space containing it must have an air vent with a minimum free area of 5cm2 for every kw maximum rated net input in excess of 7kw.So really take my advise & have a new boiler.Also i assume the system is pumped heating with gravity primaries to the cylinder,making quite an alteration if you fit new kitchen units around the old boiler.hope this info helps.
also,if there is any other gas appliance in the same room you should include the input rating of that appliance aswell in your vent sizing calculation. are you back at work yet romeo?
Thanks for the recommendation Rome60.. - not sure I follow.. flue exits through roof... but perhaps you mean an internal characteristic.. or that must have 600mm between boiler and ceiling? - vented pumped system .. yes..cylinder yes? gravity primaries to cylinder? don't follow..how would effect kitchen installation ? - extractor? ..yes having a cooking hood extractor 120mm diameter pipe. didn't think extractor fans relevant to boiler ventilation as not on permanently... unless for some boilers you can get fans triggered by boiler starting up? - on that rate need ~ 100cm^2 ventilation. slightly in excess of with manufacturers recommendation.. presumably the installation was upto standard at time not soo long ago ~ 1980's house+boiler. confess my reasoning was balancing.. if its not broke why spend £1500 to fix + are new boilers as reliable ?? vs new boiler.. smaller, more efficient.. + if have to replace now would be a good time..
Thanks.. Not sure if having a gas hob.. But.. possibly for that could take into account extractor hood?
CMF Romeos on the money, get yerself a new boiler and cut out the grief further down the road, there are loads of permutations for resiting etc,check it all out first before any final decisions. Good Luck
CMF,If the flue is vertical & straight through the roof from the boiler thats fine,just needs to be correct length when it comes through the roof whether the roof is flat or pitched.Even if it is not to current stardard you don"t have to alter the flue.In about 5 years i think open flue boilers will be obselete apart for commercial& industrial.Also if you change the boiler there is no need for vents,& fitting a unit over the boiler no problem.Coming back to your system the primary flow& return curcuit heats your domestic hot water in the cylinder without the pump running ie gravity.If you have a new boiler before the new kitchen it will save you a lot of money due to the involved upgrading your system. twoinchnipple, yes started back cuople of weeks ago since my op in january.
Thank you all.. for your advice (seems pretty conclusive you're all in agreement)..and for taking the time to respond - much appreciated. Looking again at the kitchen ventilation duct I've found that the house builders have put the "12600mm^2 free air flow" duct right in front of a timber beam and horizontal metal plate level probably support window lintel.. the only air comming/inout are through a couple of little drill holes drilled through plate.. and has no lining.. so I'll have to re-site it as matter of urgency...slightly lower to miss the obstrucions, provided this still meets regs. Cheers Clive
CMF, yes sort out the flue very important with open flue boilers.Make a new vent hole & if cavity wall make a metal sleeve same size as the hole,& fit vents (plastic)with louves not terracotta with holes.
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