Johnson and Starley Warm air boiler

Discussion in 'Plumbers' Talk' started by JBN, Oct 11, 2019 at 8:03 AM.

  1. JBN

    JBN New Member

    Hi,
    We have just purchased a house with Warm Air heading using a J&S boiler unit. We seem to have a problem with the fan running all the time when the mains electricity is on. The unit otherwise runs fine, heats the house great, but when you turn the thermostat down, even after cooling the fan doesn’t turn off.

    I have replaced the FCD & Limit switch and the capacitor as recommended by a engineer however this hasn’t seemed to solve the problem. Any thoughts? Cheers JBN
     
  2. Mike83

    Mike83 Well-Known Member

    Does it have a summer mode?
    If it does the fan will run to provide cool air
     
    teabreak likes this.
  3. JBN

    JBN New Member

    I can’t find anything on the boiler itself or in the handbook that refers to ‘summer mode’. Perhaps when I get home I could play around with the timer and see if that has any affect. However I would hope the engineer who visited would have thought of these things and the problem is a bit more obscure! Could the wiring between the FCD and limit switch be at fault? The LED screen on the front doesn’t show any fault code when operating. Cheers
     
  4. Mike83

    Mike83 Well-Known Member

    What model is it?
     
  5. JBN

    JBN New Member

    Economaire 50/intejan
     
  6. Mike83

    Mike83 Well-Known Member

    What thermostat is fitted.
    Is it a regular stat or a Johnston and starley thermista-stat.
     
  7. Mike83

    Mike83 Well-Known Member

    If it’s the thermista-stat then turning it all the way down will activate the summer mode.
    It won’t if the unit has a summer switch on the front though.
     
  8. JBN

    JBN New Member

    ADF13FD1-62D6-4549-B31F-A9AE7A47B118.jpeg image.jpg
    It’s a Johnson and Starley stat. I’ve just noticed it has a summer airflow setting, I’ve had a little play and nothing seems to be stopping the fan from spinning.
     
  9. Mike83

    Mike83 Well-Known Member

    With the heater switch at off and the stat set at 5 does it go off.
    It’s not that easy to test if it’s the stat at fault. I’m sure the stat is low voltage
     
  10. JBN

    JBN New Member

    The fan is still running with the heater off and stat set to 5. Dodgy thermostat?

    Thanks for your help on this
     
  11. Mike83

    Mike83 Well-Known Member

    That’s what I’m thinking. Not easy to test though as it will be a simple 2 wire install that controls both the heating and cooling aswell as powering the stat.
     
  12. The Teach

    The Teach Well-Known Member

    Mike83 likes this.
  13. Mike83

    Mike83 Well-Known Member

  14. Mike83

    Mike83 Well-Known Member

    So basically link between 8 and test.

    good little guide that is.
     
  15. JBN

    JBN New Member

    Thanks for all this info chaps. Looks like I’ll get a new thermostat ordered!

    Cheers!
     
  16. The Teach

    The Teach Well-Known Member

    Not many of them j&s fan flue (newest) heating systems around,often fitted on housing developments or retro fitted inlieu of previous j&s open flue warm air units.

    Its a bit cheeky :D have you got a neighbour who has same system,maybe ask to borrow their Thermista-stat for a very quick test ;)

    although there are some fault finding procedures,some are to be used when in phone contact with the manufacture they will be asking for multi meter readings from different terminals.

    tbh the new j&s wau + circulator are fairly good products but they need specialist repair/service people,getting an expert to maintain them is the idea.
    many companies will send out a gas service technician but they may have never seen your appliance before :( believe me that happens.

    Good luck:)
     

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