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Ravenheat HE120t low nox error code 28 problem

Discussion in 'Plumbing and Central Heating' started by kp411, 22 Aug 2010.

  1. kp411

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    can anyone help with this puzzle i have a ravenheat combi it displays a code no. 28 . After a reset it goes through its normal sequence then after approx 3 secs it locks out displaying the above mentioned code .the first thing i checked was the pressure it was at just over 1/2 a bar so i repressured to 1.5 bar reset and the same thing happened then next i changed the low water pressure switch and guess what no joy, checked both fuses in pcb both fine what else can keep the low pressure switch open when the pump is running can it be the c/h - h/w sensor
     
  2. transam

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    I assume that the code indicates low water pressure , when you changed the pressure switch did you make sure there was no debris ect in the part
    (tee?) that the low pressure switch was screwed into ?

    assume you bridged out the pressure switch to test ??
     
  3. kp411

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    Funny you say that because I've just been on to ravenheat and they say can't be anything other than pressure,switch or flue fuse all are ok and I take it you mean check for continuity across the terminals on the switch there are three and I get continuity across 2 off them the only thing I haven't done is check for debris or blockage what's the most efficient way of doing that
     
  4. ChrisR

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    Remove pressure switch
    wiggle small screwdriver in't ole, with a bucket handy
    replace ps.
     
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  5. kp411

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    i thought the flue fuse was one of the fuses on the pcb but apparently its not i was advised to check the continuity on either the red and white wires that lead to the flue sample point or the flue sample point itself i bridged both with a test meter and had no continuity on either is that correct and does that identify the problem and is the sample point the flue fuse im confused and tougue twisted
     
  6. transam

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    your talking about the flue stat ?? the inner flue is plastic , there fore it requires a flue stat in order to provide protection , so as the flue does not over heat / melt ? on some boilers the flue stat can alter the output of the boiler , before locking out , were as some will only work as a overheat stat eg on or off = lock out ?
    thats the general explanation ,

    you would be advised to seek some profesional help from an rgi !!!
     
  7. kp411

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    Yes I will take your advise and get a professional rgi in but still interested to know where this flue fuse is situated Can you tell me
     
  8. transam

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    Must admit we have installed quite a few ravenheat boilers (Unfortunately) but never a 120 , however the flue stat (Temperature sensor ) would normally be fitted in the flue sensing flue gas temperature , hence why tou need to obtain some profesional help !!
     
  9. kp411

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    I'm sorry but that reply makes absolutely no sense is there anyone out there that can advise me correctly on this matter
     
  10. kp411

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    Watch this space all will be revealed and explained with on the next 2 days might be able to educate even you rgi's out there
     
  11. transam

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    Education is always welcome , it should never be assumed that any rgi has knowledge of every boiler currently on the market .

    The problem with Ravenheats is that most installers who value there reputation would not install them , I un-fortunately did not listen to this advice at the time & installed numerous ravenheat CSI boilers , if you go into my pictures you will see the end result of there award winning :) A rated boilers ! I sincerely hope that the quality of the components & manufacture is better on your 120 ?? hope it go's well , see you later !
     
  12. picasso

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    I cant find any mention of a fluestat in the instructions or the wiring diagram, so I would go with chrisr on this one.
     
  13. kp411

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    Well problem resolved the code 28 on the ravenheat he csi120 means low pressure ,a faulty low water pressure switch or a faulty " flue fuse" ok no mention of flue fuse anywhere in the manual or the Internet that's just what ravenheat technical call it .It screws into the flue some might call it a stat it certainly looks like one . The only description that remotely resembles it is a "flue fuseable link "but there is no images to check , It was a case of order and see, it turned up complete with wireing loom as well and only cost about £16 plus carriage.I hope someone learns from this and doesn't have to go without a boiler for as long as I did for something so simple
     

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