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Discuss Open Flue and Ventilation query in the Gas Safe Register Forum - Public Forum area at

  1. Donald777

    Donald777 Guest

    Hi, my first post here,
    I rent out a property with a open flue Johnson & Starley warm air heater (installed in the house in 1978!). The property is currently empty so I ran the heater for 30 mins to check it all worked OK, which it seemed to. A gas safety check was passed a few months ago. However I noticed a slight gas smell with the heater turned off which I though might be the gas valve needing some grease (I'd lived in the property years ago and an engineer had fixed it with grease so I suspected the same problem. The rental agency arranged for an engineer on there books to look at it. He phoned me to tell me:
    1. Gas leak on inlet valve - (as expected)
    2. Ventilation sub-standard - the heater is housed in a cuboard on the landing and there is a warm air outlet vent just below the cuboard and the a return air duct just above the cuboard - he advised that it should'nt have both this outlet and return in the same room.
    3. Flue sub-standard above warm air unit (he explained on the phone that there was a right angle in the flue just above the unit because of a joist.
    4. Return air-duct sub-standard - there is a 1inch gap in the ducting inside the heater cuboard between the grill and the ducting. This same ducting sits on top of the heater unit but is not screwed on to it. It should be screwed on and taped to seal it.
    5. Flue terminal, not connected to flue. He explained the flue was unsupported in the loft and the underside of the ridge tile had disintegrated perhaps because of the weight.
    He advised that it would be best to fit a conventional wet system (~£4600).

    Obviously a bit shocked I looked at the system myself, just to come to terms with things myself. I also called a heating engineer myself and he looked at things. Regarding:
    2/ The new engineer said that it's not a problem have the return duct in the same room (the landing) as one of the warm air outlet ducts (registers?).
    3/ There is no right-angle in the flue but there are a couple of 30 or 45degree elbows to get the flue to come up under the ridge tile in the roof but at no time is the flue anywhere near horizontal.
    4/ I can see the 1 inch gap problem here myself and so did the new engineer. Perhaps the whole unit has moved back on the plenum or per it was never fitted correctly.
    5/ I can see both the flue and the venilation air-vent (that carries the air required for combustion) going up through the loft to two separate ridge tiles. They both appear to be connected, I'll try to get really close tomorrow for a detailed inspection. The new engineer didn't seem concerned about them.

    The new engineer found two further problems though (call these 6 and 7):
    6/ The heater unit was not securely fixed to the plenum and could move.
    7/ The air vent that comes down from one of the ridge tiles is split just inside the top of the cuboard with one open end right at the top of the cuboard and the other continuing down to about a foot from the bottom. He explained that new regulations require each to have it's own vent to the outside air, they can't share a vent then split.

    The new engineer is going to give me a quote for a replacement warm air unit from Johnson & Starley. We discussed the alternative new systems but I've tenants that need to move in, in 2 weeks and am worried that putting a wet system in would make mess and require carpets to be relaid and redecorating etc.

    As there seem to be some serious differences of opinion about what is wrong with the system I thought I'd try to lookup the regulations myself. I've got as far as discovering BS5440-2:2009 but see that it's about £150. Then there's the challenge of reading and understanding it!

    Do these new regulations apply to existing systems when they need repair?

    I'd be grateful for any advice anyone has to offer, either on the problems or my best option. Ideally I'm hoping to hear that the existing system could be repaired and made safe for much less than a new warm air unit would cost to install. The second engineer explained that J&S were the only firm making warm air units for the UK now so could name there price to some extent. I'll make sure I'm sitting down when he calls with his quote!

    I gather that CO detector would be a good idea as these open flue units are intrinsically less safe than sealed units.

  2. Mbear

    Mbear Guest

    The WAU set up can be confusing and as so I wouldn't like to comment without seeing the majority of the issues with my own eyes. But if your gona pay to replace the system then I'd suggest that you get a combi in, there's far less issues to worry/think about.

    Ps if your flue terminal is disconnected from the flue then I'd be inclined to classify this as AR (AT RISK). However I'd want to double check that in the unsafe sits book.
  3. prs1

    prs1 Guest

    Iam a gas fitter although not ticketed in WAU but i can tell u that if u are having work carried out it needs to be to current standards.
    The standards may have changed alot over the years on these but that is partially because when they go wrong they can kill poeple.
    If your concerned about your tenents bite the bullet and get rid of this open flued appliance,for a couple of room sealed combis which will save you money over the coming years.
    Just the fact it leaking gas for a second time ,it in a cupboard might add up to no property 5 years down the line.
    IMHO ud be mad to buy a new WAU when u have alternatives.
    Good luck
  4. Donald777

    Donald777 Guest

    Thanks for your reply Mbear. I'd better check-out the Combi possibility rather than dismiss it due to the radiator/pipework installation upheaval.

    About the AT RISK classification etc. he may have done this, he put a WARNING sticker on the unit and disconnected the gas and capped.


    Thanks Paul (prs1), that makes two on here advising to take the combi option. It is just one 3-bed house that I rent as a house (rather than split into flats etc) so I'm only after the single heater unit. If I can't find an engineer to safely repair the existing system, I'll get the second engineer to quote for both combi and non-combi (with water on Economy 7 as at present) too I think.
    Last edited by a moderator: May 9, 2010
  5. prs1

    prs1 Guest

    No harm in checkin it out pal

    If hes cu and capped supply to WAU hes classed it as "ID" immeadiatly dangerous.
    Last edited by a moderator: May 9, 2010
  6. migoplumber

    migoplumber Guest

    cutting and capping is done to both at risk and immediately dangerous situations.

    i would advise along the combi/system boiler as well.

    anything with a balanced flue. there is no reason to install an open flued appliance in any domestic property.
  7. prs1

    prs1 Guest

    Migo- at risk action is turn off appliance or supply and issue warning notice-with customers permission otherwise your phoning transco.

    ID- disconnect(with customers permission) and issue warning notice,again if they will not give permission phone call to transco who will disconnect.
  8. Plucky

    Plucky Guest

    never bad practise to cut and gap an At Risk situation if the customer allows you to do so.
  9. migoplumber

    migoplumber Guest

    i dont give the client a choice. i cut and cap AR & ID - then inform the client, and ask for permission. if its refused then they can call the supplier for help. my conscious is clear.
  10. Puddle

    Puddle Plumber

    Agree,as far as I am concerned,they have allowed me to work on installation and that is permission enough for me
  11. Mbear

    Mbear Guest

    I see alot of folk agreeing that an At Risk is automatically a cut and cap.

    At Risk means that there is a RISK of an ID type situation coming to fruition. So if a back boiler has no vent, this would be cut and capped? Of course not, the most you should do is turn the gas and elec off to the BBF with the customers permission, label it AR and leave the relevant paperwork. By doing this you are folowing the unsafe sits procedure correctly and you let the cust know that if they turn the gas & elec back on and use the BBF again then it's their resposibility if anything happens as you have warned them about the issues and they have signed to say they had read and understood the paperwork.

    Cut and cap is for ID. When an appliance IS spilling or HAS a gas leak. An immediate danger to life or property.

    I think be cautioun about safety issues is good obviously. But you can be overly cautious. If you cut and capped every back boiler with no vent then alot of folk wouldn't have any heating.
  12. Puddle

    Puddle Plumber

    Yes and a lot of folk would be alive

    If I go to a back boiler with no ventilation I cap off as ID,if ventilation undersized or incorrectly positioned I would class as AR,if burning correctly ,I may leave on if requested in this instance but depends on each siduation

    Same as if I go to a back boiler and the front room is being used as a bed room,boiler maybe working ok and ventilation ok but would cap off

    I do not want dead customers and bits of paper saying it is ok for me to leave them to die

    I want live customers even if it means them ringing me up and shouting and whinging at me

    I have had arguments with customers at the time but when things sorted out,by me or another, most will say thank you when you see them at a later date

  13. Mbear

    Mbear Guest

    I'm sorry puddle but At risk does not mean cut and cap. A bbf with no vent is AT RISK therefore no cap is necessary as per unsafe sits June/July 09 IIRC.Ie more than 90% ventilation free area provided is ok. Less than 90% is AR and turned off/labelled.

    I'm talking about this issue as a standalone issue. Ie everything else is spot on with flue,spillage,flue flow,no gas leaks,no signs of distress. If any of these issues are apparent along with the No vent then it's an entirely different scenario of course.
  14. Blackcatgas

    Blackcatgas Plumber GSR

    One mans at risk is another mans Imediately dangerous, I use my own judgement , better to err on the side of caution than try and argue in court as to why you didnt take any action, this is why I hate doing landlords certs as if you look hard enough you will always find a problem. I dont have the best people skills, I have 2 settings, chilled out, and ready to punch somone in the face when custards question somthing Iam doing for thier safety.Having said that in 13 yrs Ive only had to shut down 2 apliances
  15. Puddle

    Puddle Plumber

    Thought you was going to say
    In 13 yrs Ive only had to punch 2 custards in the face :D:eek::p
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