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Gas boiler Operating.

  • 13-12-2010 8:19pm
    #1
    Registered Users Posts: 10,262 ✭✭✭✭


    Hi Folks...

    Wondered if you can help. Was asked a question today i have not been asked in a while... Brother has a gas boiler thats 15 years old and sounds like its just about to set down...A couple of leaks...heatexchanger pump... etc...

    Anyway traditionally what i would have done there is supply a boiler with a cast iron heat exchanger somethine like a suprima or a glowworm. You know why..the dirt etc...

    Just wondering since condensing boilers have come in the standard seems to be aluminium heat exchangers which off course is prone to blocking...or are they...


    The simple question i am asking is...what is now supplied for the retrofitting of a boiler...is it a condensing one with a fabricated heat exhanger and a serious system flush or is it something else...

    Many thanks for parting with the knowledge....


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Comments

  • Closed Accounts Posts: 870 ✭✭✭knighted_1


    condensing boiler - fit a magnacleanse , cleanse and inhibitor -

    above is not worth a fcuk unless the gas installer gas rates the appliance as most that were fit are overfiring and thats why the heat exchanger cracks and leaks


  • Closed Accounts Posts: 3,305 ✭✭✭yoshytoshy


    It doesn't take a lot to clean heating systems. Glowworm and worcester have large openings within the exchanger.
    Boilers like baxi megaflo ,have a smaller bore exchanger and the system needs to be powerflushed before they're installed.
    I've been to technical courses for a lot of boilers and I've seen the inside of exchangers and other parts etc.

    Getting a 15kw boiler is better for replacing existing boilers in most houses as the 24kw needs a lot of gas ,larger pipe.


  • Registered Users Posts: 1,632 ✭✭✭heinbloed


    The (modulating) condensing boilers come equipped with their own build-in heat exchangers. As being part of the condensing modus at which they run efficiently these shouldn't be altered.

    There are various types of materials, what we look at being aluminia could be an alloy with far better corrosion resistance at the combustion side than the very cheap aluminia ones. I'm not sure if aluminia on its own is still used for this purpose.
    The combustion heat exchanger should be inspected and cleaned anyhow once per year, it's part of the anual service and important for the efficient and safe operation.
    Some manufacturers use ceramic instead of alloys.
    Clogging-up of heat exchangers ( the primary/central heating loop) can be avoided by a mud-trap at the lowest point.



    The installation issue itself asks for a flue system suitable for condensat to drain-off. Standard flues designed for higher temperatures don't allow for this, the condensate issue didn't arise with the old boilers.

    Check first how the new flue will be integrated, the shortes way(straight through the wall) might not be available, the lining of the old flue can be done but is more labour- and material intensive ...


  • Closed Accounts Posts: 3,305 ✭✭✭yoshytoshy


    heinbloed wrote: »

    The combustion heat exchanger should be inspected and cleaned anyhow once per year, it's part of the anual service and important for the efficient and safe operation.

    This is wrong for a lot of condenser heat exchangers ,some have a silicone mixture that can be damaged if scraped.

    It's important if people give advice on this forum that they know what they're talking about.


  • Registered Users Posts: 1,632 ✭✭✭heinbloed


    Please publish a link to this 'information', yoshytoshi.

    The combustion chamber MUST be inspected (and cleaned if necessary) at EVERY inspection. It is a vital part of the job, vital by it's very means.

    The heat exchanger IS part of the combustion chamber.....

    Further on the ENTIRE flue must be visually inspected and cleaned at each inspection.

    The heatexchanger is part of the flue.....

    "
    It's important if people give advice on this forum that they know what they're talking about. "

    Why is that important, yoshytoshy?


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  • Closed Accounts Posts: 870 ✭✭✭knighted_1


    yoshytoshy wrote: »
    .

    It's important if people give advice on this forum that they know what they're talking about.

    lets see if you do - you recomended a 15kw boiler - how many cubic metres per hour would that use or call for ?


  • Closed Accounts Posts: 3,305 ✭✭✭yoshytoshy


    knighted_1 wrote: »
    lets see if you do - you recomended a 15kw boiler - how many cubic metres per hour would that use or call for ?

    I've a better one for you ,whats the maximum lent of 15mm copper allowing 1.5 cubic metres of gas ?


  • Closed Accounts Posts: 3,305 ✭✭✭yoshytoshy


    heinbloed wrote: »
    Please publish a link to this 'information', yoshytoshi.

    Why is that important, yoshytoshy?

    I couldn't two flying hoots ,whether I post on this forum or not.

    Good luck.


  • Posts: 0 [Deleted User]


    heinbloed wrote: »

    Further on the ENTIRE flue must be visually inspected and cleaned at each inspection.

    Why?


  • Registered Users Posts: 1,632 ✭✭✭heinbloed


    Gary71 asks why the flue of a combustion device should be inspected ...

    Anyone out there? Yoshytoshy?


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  • Registered Users Posts: 2,789 ✭✭✭slavetothegrind


    heinbloed could you please calm down a bit, you are managing to raise everyones hackles here whether you realise it or not.

    You have stated previously you are not a plumber where others here are well experienced professionals, if you question their opinions please do so with respect and we'll all learn something in the process.

    Every day is a school day for most of us:)


  • Posts: 0 [Deleted User]


    OP, if it were me I would be thinking about a good heat pump, failing that flush, flush and flush again it's not all about the heat exchanger other bits get shagged as well, +1 for the magnaclean with the larger connections and go with something with a long warranty, i can pm you with where you can get a decent boiler if you unsure about the stuff you sell:pac:


  • Closed Accounts Posts: 3,305 ✭✭✭yoshytoshy


    gary71 wrote: »
    i can pm you with where you can get a decent boiler if you unsure about the stuff you sell:pac:

    What boilers do you work on most gary ?

    I'm a worcester fan myself.


  • Closed Accounts Posts: 870 ✭✭✭knighted_1


    yoshytoshy wrote: »
    I've a better one for you ,whats the maximum lent of 15mm copper allowing 1.5 cubic metres of gas ?[/QUOTE

    who said anything about 15mm

    if you put 1.5 m3 in to your 15 kw boiler you are going to overfire it by 2 kw -
    1.5 x 11.39 = 17.08kw


  • Closed Accounts Posts: 3,305 ✭✭✭yoshytoshy


    knighted_1 wrote: »
    yoshytoshy wrote: »
    I've a better one for you ,whats the maximum lent of 15mm copper allowing 1.5 cubic metres of gas ?[/QUOTE

    who said anything about 15mm

    if you put 1.5 m3 in to your 15 kw boiler you are going to overfire it by 2 kw -
    1.5 x 11.39 = 17.08kw

    You've lost me ,seriously.

    Boiler fans dictate the volume of gas going into a boiler ,apart from that it's the pipe that dictates it.

    If you're going to start talking about rating a boiler etc. ,any boilers I've installed for the last three years are condensing.


  • Posts: 0 [Deleted User]


    yoshytoshy wrote: »
    What boilers do you work on most gary ?

    I'm a worcester fan myself.

    I bitch way to much to say, if the fruit loops find out I'm moaning about them here then they won't buy my boilers(which are bloody good).


  • Registered Users Posts: 10,262 ✭✭✭✭Joey the lips


    Right that has been a fair deviation.....

    So is the answer that there is no cast iron heatexhangers available in condensing boilers so the only way to go is

    Flush Flush and flush again...

    which off course will no doubt cause a pin hole leak some where obsecure so off course dont forget the leak sealer....


  • Registered Users Posts: 1,632 ✭✭✭heinbloed



    ....So is the answer that there is no cast iron heatexhangers available in condensing boilers so the only way to go is

    Flush Flush and flush again...

    which off course will no doubt cause a pin hole leak some where obsecure so off course dont forget the leak sealer....


    Well, the condensing boiler's heat exchanger is the last thing that would fail because of rust, in a rust-prone installation....
    If the rest of the system is made of brass or stainless steel or of a similar corrossion restitant material then no inhibitor or flushing is necessary.

    There would no build-up of sludge in the best case scenario.

    My own central heating system (condensing boiler with alloy heat exchanger) has never had anything but clean drinking water, straight from the well.
    And is running since 7 years like that. No flushing, no inhibitor, sometimes topping up the pressure. With clean drinking water.


  • Registered Users Posts: 10,262 ✭✭✭✭Joey the lips


    heinbloed wrote: »
    Well, the condensing boiler's heat exchanger is the last thing that would fail because of rust, in a rust-prone installation....
    If the rest of the system is made of brass or stainless steel or of a similar corrossion restitant material then no inhibitor or flushing is necessary.

    There would no build-up of sludge in the best case scenario.

    My own central heating system (condensing boiler with alloy heat exchanger) has never had anything but clean drinking water, straight from the well.
    And is running since 7 years like that. No flushing, no inhibitor, sometimes topping up the pressure. With clean drinking water.

    Please understand....i am not asking you about yours. I am asking a direct simple question.

    In a boiler retrofit where traditionally because of build up of sludge etc when a boiler was changed usually one with a cast iron heatexchanger was used...

    What is the procedure now seen as though a lot of the condensing boilers dont seem to have them..


  • Posts: 0 [Deleted User]


    What is the procedure now seen as though a lot of the condensing boilers dont seem to have them..

    Requirements havn't changed, people's understanding has, if you put a Potterton Netaheat on a dirty system your going to have issues. Your right a modern bolier has to have clean system water, so have a look at the water if you have no signs of sludge or solids you may get away with a cleaning chemical and then flush asper manufactures instructions, personally I would power flush and fit a magnaclean as a given.


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  • Registered Users Posts: 10,262 ✭✭✭✭Joey the lips


    gary71 wrote: »
    Requirements havn't changed, people's understanding has, if you put a Potterton Netaheat on a dirty system your going to have issues. Your right a modern bolier has to have clean system water, so have a look at the water if you have no signs of sludge or solids you may get away with a cleaning chemical and then flush asper manufactures instructions, personally I would power flush and fit a magnaclean as a given.

    So really its use a new boiler and possibly powerflush....

    Has anyone any experience how a pex system responds to a power flush.

    Just while I am asking.


  • Closed Accounts Posts: 870 ✭✭✭knighted_1


    yoshytoshy wrote: »
    knighted_1 wrote: »

    You've lost me ,seriously.

    Boiler fans dictate the volume of gas going into a boiler ,apart from that it's the pipe that dictates it.

    If you're going to start talking about rating a boiler etc. ,any boilers I've installed for the last three years are condensing.

    so ,when you install a condensing boiler what do you do ? do you not gas rate it ?


  • Posts: 0 [Deleted User]


    knighted_1 wrote: »
    yoshytoshy wrote: »

    so ,when you install a condensing boiler what do you do ? do you not gas rate it ?

    I don't, I'd like to know why you do.


  • Closed Accounts Posts: 870 ✭✭✭knighted_1


    gary71 wrote: »
    knighted_1 wrote: »

    I don't, I'd like to know why you do.

    because its the law? IS 813 section 15.1 - comissioning appliances

    three lines down

    -that appliances are adjusted to thier correct gas rate


  • Posts: 0 [Deleted User]


    knighted_1 wrote: »
    gary71 wrote: »

    because its the law? IS 813 section 15.1 - comissioning appliances

    three lines down

    -that appliances are adjusted to thier correct gas rate

    How would you adjust a codensing boiler?


  • Closed Accounts Posts: 870 ✭✭✭knighted_1


    on the throttle on the gas valve ,where would you throttle back ?


  • Posts: 0 [Deleted User]


    knighted_1 wrote: »
    on the throttle on the gas valve ,where would you throttle back ?

    I don't, I have a working pressure of 20 mbar and a fan controlled by the pcb, you can on some boilers mess with the fan speed but it's not advisable as it can effect flame picture and stability if done incorrectly.

    (setting the co2% is a given)


  • Closed Accounts Posts: 870 ✭✭✭knighted_1


    gary71 wrote: »
    I don't, I have a working pressure of 20 mbar and a fan controlled by the pcb, you can on some boilers mess with the fan speed but it's not advisable as it can effect flame picture and stability if done incorrectly.

    you really should upskill gary -nothing to do with the fan speed its to do with the volume of gas multiplyed by the calorific value(11.39) to get the kw input (most manufacturers set the rate at the english calorific value 9) post any boiler make ,give me the kw and the manufacturers recomended gas rate on max and i will show you why they overfiring

    http://www.boards.ie/vbulletin/showthread.php?t=2055804301&page=2

    ring martin and ask him how to set up a condensing boiler -he told me most people setting them up wrong (or not setting them up) thats why they overfiring

    edit - i googled martin and the first result is a post by you about him so i presumed you know him


  • Posts: 0 [Deleted User]


    knighted_1 wrote: »
    you really should upskill gary -nothing to do with the fan speed its to do with the volume of gas multiplyed by the calorific value(11.39) to get the kw input (most manufacturers set the rate at the english calorific value 9) post any boiler make ,give me the kw and the manufacturers recomended gas rate on max and i will show you why they overfiring

    http://www.boards.ie/vbulletin/showthread.php?t=2055804301&page=2

    ring martin and ask him how to set up a condensing boiler -he told me most people setting them up wrong (or not setting them up) thats why they overfiring

    edit - i googled martin and the first result is a post by you about him so i presumed you know him

    yep, I know him very well so you should ask him about my skill set, as for up skilling I try to do that every day so I'm more than happy for you to tell me where I'm going wrong.


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  • Closed Accounts Posts: 870 ✭✭✭knighted_1


    well i did try - either he trained me wrong or you are right - you tell me which
    i dont doubt your skill set but not gas rating a condensor boiler is wrong and if you ask him you could clear up weather i am wrong and you are right -


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