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Honeywell Prestige

ChasMan Member Posts: 459
The honeywell prestige, like most other thermostats has the arangement below. When the R / Rc connection link is removed, can R & W be considered an isolated contact? Ie, if I allready power the stat from C and Rc with one transformer, I would asume there is no need to worry about R & W getting any juice from C or Rc correct? I wish these things were like Tekmar where you put 24 volts in to light it up but then have a completely seperate relay to do with what you want.




W -------O HEAT

Y -------O COOL

G -------O FAN RELAY


  • JStar
    JStar Member Posts: 2,752

    R and RC are separate contacts made just for the use of two different transformers.
  • Wayne_16
    Wayne_16 Member Posts: 130
    R-C & Rc to Y, G

    R to W makes one set of contacts in the thermostat, (heating cycle).  Rc to Y, G & or Y- G is  the other set of contacts, (cooling cycle) allowing 2 separate transformers to operate off of one thermostat.  C completes the circuit of the R terminal to operate displays and lights.  Connecting both transformers to the C terminal may be a problem if the transformers are not in phase with each other.


    Minnesota Wayne
  • ChasMan
    ChasMan Member Posts: 459
    edited April 2010
    C & RC or C & R Power Stealing

    Thanks Guys.

    Wayne, You Said

    "C completes the circuit of the R terminal to operate displays and lights"

    That seems perfectly logical to me however, in the I&O manual for this thing under the 1H / 1C with 2 transformers, it says for the RC Terminal :

    Remove jumper from R to RC terminal for systems with 2 transformers. Common connection must come from the cooling transformer.

    That threw me because that tells me it is getting power from C & Rc not C & R which seemed kind of odd.

    This is not what is called power stealing is it? This is a powered stat. Ie, it needs to see full boat 24 VAC.
  • Mac_R
    Mac_R Member Posts: 117
    Prestige Wiring

    I have had the pleasure of installing this thermostat.  I am using it on a New Yorker Boiler with a Taco Zone control.  Rc powers the unit and uses C as a common.  I had to remove the jumper between Rc and R in order for the stat to work.  I used the 24 volts off the zone control for Rc and C.  I then hooked the thermostat wires from the zone control to R and W. 
  • ChasMan
    ChasMan Member Posts: 459

    Well, I finally got around to installing this thing over the weekend. As a thermostat, running double duty between hydronic heat and forced air A/C I would call it adequate. There is almost enough flexibility to get it to do everything I want.

    I have a few of questions if anyone is familiar.

    1: The outdoor temp sensor seems accurate but the humidity sensor is off by about five points or so. The manual mentions you can set an offset but in the setup screen, the option does not appear. Anybody else have this issue?

    2: The fan operation can be set to ELECTRIC or OIL / GAS :-) Basically, if it is set to OIL / GAS, the fan relay is not energized on a call for heat. The problem is though that the stat thinks the heating system has its own fan and refuses to circulate the A/C fan while the heating system is energized. Worse, when the call for heat is satisfied, the circulate mode of the fan thinks the fan has been on the entire time. There doesn’t appear to be a way to get the system to operate properly which is odd as you would think that my setup is not that abnormal. I set it to Electric heat so that the fan would come on with a call for heat. I like to circulate the air for the air cleaner. And Id like the circulate function to operate independently of the heating system. I know I could add a separate stat for heat or a fan circulator control but I was looking for a one box solution. Any ideas on this?


  • ChasMan
    ChasMan Member Posts: 459

    Well, just got off the phone with Honeywell tech support, they seem confused. I don't think this thermostat was ever intended to be used in a radiant / panel / radiator type heating system combined with an air handler. I'll give it the close but no cigar award. Can't wait to get a multi speed air handler so I can leave it on low or something.
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