Centaurstat 7 problem

Discussion in 'Plumbers' Talk' started by justint, Dec 5, 2007.

  1. justint

    justint New Member

    I have a Horstmann Centaurstat 7 programmable room stat. It gives the appearance of working OK. It clicks at the right times etc but the heating circuit in the zone that it controls doesn't close down when it reaches the set temperature (even 0ยบ/off), despite the appropriate click.

    Normally I have the H37 programmer set to constant for this zone. If I change this to off or timed it switches everything off correctly. Even if I remove the Centaurstat body from the backplate the circuit continues to work (if on at the programmer)

    I tried a re-set (set and enter buttons together) to no avail. Would a replacement unit solve the problem or is it something else?

    This is not a new fix. It has been working fine for 6 yrs.

    Any suggestions most welcome. Many thanks.
     
  2. Bassrock

    Bassrock New Member

    Mmmmm

    It may click, but have you or can you measure the output contacts with an avo/meter or similar i.e try and establish if it is actually switching.

    All I can think of
     
  3. justint

    justint New Member

    Thanks. Will try tomorrow. Would you expect the circuit to be "on" with the unit removed? Essentially, I have three unconnected leads.
     
  4. justint

    justint New Member

    Unfortunately couldn't access the outputs with the stat in place on the baseplate. However 240v between each of the call (yellow) and common (red) in relation to neutral (blue).

    That is with no stat in place, just the baseplate with exposed terminals. No voltage when turned to off at the programmer

    Tested for continuity between the prongs of the stat when removed. (Lower fits to common on the base plate, middle to call and upper to neutral)

    Continuity between lower and upper when set to low temp; lower and centre when set to high temp.
     
  5. justint

    justint New Member

    Apologies. In relation to last posting,

    Correction

    *Upper prong not connected to neutral. The neutral lead is connected to a blank on the base plate above the upper prong which itself has a blank connection*
     
  6. Bassrock

    Bassrock New Member

  7. Mojojl59

    Mojojl59 New Member

    I have just bought a horstman centaurstat 7. When i remove the unit from the baseplate the screen goes blank even though it has batteries fitted is this normal or should the batteries keep the screen display vissible
     
  8. No idea.

    It certainly seems unusual in that most battery-operated 'stats would keep the display going even when removed from the backplate; they certainly don't 'use' the boiler power from the backplate for the display.

    However, perhaps the Cent7 is more sophisticated and has a wee microswitch on the back that turns the display off when removed so it conserves power if not fitted? Does the display return when it's just about to be pushed 'home'?

    I presume that, when it's replaced, it returns to the correct time and settings as before? In which case it would appear to be 'working' ok.

    Drop Horstmann an email, 'cos I don't have a scoob.
     
  9. Mojojl59

    Mojojl59 New Member

    Thanks you not totaly sure nyself works fine when put into backplate and timings are correct. Will have to email horstman
     
    Deleted member 33931 likes this.

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