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Paging Tony Agile!!

Discussion in 'Plumbing and Central Heating' started by PullerGas, 1 Aug 2015.

  1. PullerGas

    PullerGas

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    Tony
    You had a tip a few years ago for testing boiler thermistors. A wee setup which included a Pot & resistors. Could you please share it again in the combustion chamber pot.
    Many thanks.
    Dick Puller
     
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  3. Gasman28

    Gasman28

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    That will be £84 please :mrgreen:
     
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  4. Terry lambert

    Terry lambert

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    You sure it wasn't gasguru ?
     
  5. PullerGas

    PullerGas

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    No, I think it was Tony but I can't be certain.
     
  6. picasso

    picasso

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    If your testing the thermistor you ned a multimeter, if your testing the boiler you need a pot and a resistor in series (to stop the pcb seeing zero resistance) not sure what else you would need ?
     
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  7. PullerGas

    PullerGas

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    Yeah it was the Pot & resistor in series mate. Has Tony f.cked off to France again on his holibags???
     
  8. DP

    DP

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    Puller, look at the MIs, what is the minimum resistance the thermistor is going to indicate i.e. at max temperature.
    That will be value of the resistor you need (Ideal Icos 85 degree resistance value is 1k)
    25 degree resistance is 9k7 to 10k3

    I would pick 1k resistor and 10 k pot. Solder the resistor to middle connection on the pot. connect one (test) wire to other leg of the resistor and another (test) wire to right hand connection on the pot

    Minimum setting would indicate 85 degrees and full travel of spindle on the pot about 25 degrees.
    If you want reverse reading, move the outer wire to the tag that is 'spare'
     
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  9. Gasguru

    Gasguru

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    You mean this....knocked up to solve the fault codes on a Microgenus II that weren't in the book or known by Ariston tech.

     
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  11. Terry lambert

    Terry lambert

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    That's the one
     
  12. simond

    simond

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  13. PullerGas

    PullerGas

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    Thanks everyone. I've just found one I made up a few years ago, but the ones details do give a huge range.
     
  14. Agile

    Agile

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    I would be more inclined to use a 20k or 25k pot ( or switch an extra 10 K resistor in series ) .

    That is so that I can test the frost protection function which many boilers have.

    The best ones have two features, run pump below 3 C and start burner below 1 C. Approximate temperatures. Usually activated at about 17 k or more.

    Tony
     
  15. Remington

    Remington

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    Hi im relatively new to this, just waiting for my gas safe to come through now, why would you need resistors ect? can you not just use a multimeter?
     
  16. Agile

    Agile

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    This is to see how the boiler responds to certain values of NTC sensors.

    A multimeter cannot do that!

    Tony
     
  17. Remington

    Remington

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    oh ok, so to see if the pcb is working correctly?
     
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