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  1. #27
    Join Date
    Feb 2007
    Posts
    999
    DocHoliday wrote in part:

    With the honeywell stat, I dont know the algorithems, but No, what he is saying is, it will internally raise the set point 1 degree every 5 minutes until your new set point is reached....
    This was originally confusing to me, whether he was relating his experience using a Honeywell TS with a Mod. If not, I would have liked to hear how the Mod stat handled it.

    Lets make it easy using simple numbers... Lets say you have the furnace set at 60 at night and 70 in the day. (10 degrees). Lets also say you have the time set for 7am.
    at 6:10ish, the set point will be 61. At 6:15 the set point will be 62 and so on. Granted, this is not the patented honeywell recovery, but it will bring the furnace up to 70 degrees at 7 am without doing it all at once and odds are that unless it's a brutally cold day, the furnace will stay in low fire for most of the time. BTW, this can be turned off too.
    O.K., let's change the scenario a little. Using the Mod stat, say that I go away for a couple of days, set the TS to hold at 55. On return, I go to 'run program' (set point: 68). Since the TS is controlling modulation, and sees a temperature differential of 13 degrees being called for, wouldn't it go to high fire immediately? If this is the case, with adaptive recovery disabled, and using the same setback, wouldn't the Mod go directly to high fire on programmed recovery?

    This is how my current furnace (recovery) is configured. On all but the coldest mornings, it'l take less than an hour to recover. I would like to be able to do the same with a Mod.

    AM

  2. #28
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,635
    The mod stat will call for high fire immediately when not in a programmed recovery. My customer is a bit of a techno-phobe and prefers to use the stat manually.

  3. #29
    Join Date
    Jan 2008
    Posts
    85
    Quote Originally Posted by ampulman View Post
    DocHoliday wrote in part:



    This was originally confusing to me, whether he was relating his experience using a Honeywell TS with a Mod. If not, I would have liked to hear how the Mod stat handled it.



    O.K., let's change the scenario a little. Using the Mod stat, say that I go away for a couple of days, set the TS to hold at 55. On return, I go to 'run program' (set point: 68). Since the TS is controlling modulation, and sees a temperature differential of 13 degrees being called for, wouldn't it go to high fire immediately? If this is the case, with adaptive recovery disabled, and using the same setback, wouldn't the Mod go directly to high fire on programmed recovery?

    This is how my current furnace (recovery) is configured. On all but the coldest mornings, it'l take less than an hour to recover. I would like to be able to do the same with a Mod.

    AM

    I figured I didn't explain it fully the first time.

    Setpoints: 09:00pm 60 degF
    06:00am 68 degF

    Old setup: 75K Armstrong 80% "Builders Special" and Honeywell stat.
    The stat would call for heat up to 1.5 hours prior to the
    setpoint time(04:30am for me). 1.5 hours would be for a really
    cold day when it's below zero(F).

    New setup: 75K Rheem mod and mod stat.
    Recovery start time is based on inside ambient temperature.
    If it's 60 degF inside and it needs to recover to 68 degF, then it
    will call for heat (5 * (68 - 60)) = 40 minutes early.
    That would be 05:20am for me but not early enough to keep
    the cute half happy.

    Both stats setup for best recovery algorithm. The Honeywell stat
    actually has two temperature sensors; one for inside air temp, the
    other a thin film that clamps against the wall when the unit is
    mounted to measure the building mass temperature.

    I don't know what "adaptive recovery" is. The Rheem manual calls
    theirs "Energy Management Recovery".

    I believe the Rheem mod stat will call for a 100% fire rate when
    the difference between the room temperature and the desired temperature
    is fairly large, like 4 degrees F. My furnace *seems* to run at
    full bore when bringing the house back up to temperature.

  4. #30
    Join Date
    Feb 2007
    Posts
    999
    Quote Originally Posted by Irascible View Post
    The mod stat will call for high fire immediately when not in a programmed recovery. My customer is a bit of a techno-phobe and prefers to use the stat manually.
    Thanks for that. Would you be able to describe how it would behave on programmed recovery under similar circumstances?

    My TS is programmed to recover at 6:00 A.M (it has no intelligence). Sometimes, I will wake up earlier and manually goose the TS to 68 degrees.

    I want to step up from a single stage to a Mod and in addition to manual control (as you described), would like the ability to have programmed 'fast heat' in the early morning (with or without adaptive recovery).

    Is this possible?

    AM

  5. #31
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,635
    Good questions amp. I wait eagerly with you for the answer. I'm only now getting my feet wet with the Mod. The specific logic built into the Mod stat is beyond my expertise at this moment - partly because my customer doesn't care about programming.

  6. #32
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,803
    The Honeywell stat
    actually has two temperature sensors; one for inside air temp, the
    other a thin film that clamps against the wall when the unit is
    mounted to measure the building mass temperature.



    What model Honeywell is this?
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  7. #33
    Join Date
    May 2006
    Posts
    281
    Question for everyone that has installed in the past or currently installing the MOD furnace.. Has anyone tried the new White Rodgers Tstat, Rheem had them design for the MOD furnace? Its the MOD version of the new 1F95/1F97 -1277 touch screen stat?

    Martin
    whaaaaa, you let all the smoke out

  8. #34
    Join Date
    Jan 2008
    Posts
    85
    Quote Originally Posted by beenthere View Post
    The Honeywell stat
    actually has two temperature sensors; one for inside air temp, the
    other a thin film that clamps against the wall when the unit is
    mounted to measure the building mass temperature.



    What model Honeywell is this?
    CT3600 Might have the "A" suffix too, not clearly marked.

  9. #35
    Join Date
    Apr 2004
    Posts
    7,680
    Im not sure where the confusion is...

    If it's a programmed recovery, it will use the recovery program or algorithem, if you turn it up, or manually bring it out of a hold scenerio, it will imediately jump to high fire regardles of the brand.

    Yes, the WR touch screen stat is the base design for the Mod stat, however, the standard WR stat does not have the v terminal that is required to run the mod (nor the software).

  10. #36
    Join Date
    Feb 2007
    Posts
    999
    Quote Originally Posted by docholiday View Post
    Im not sure where the confusion is...

    If it's a programmed recovery, it will use the recovery program or algorithem, if you turn it up, or manually bring it out of a hold scenerio, it will imediately jump to high fire regardles of the brand.

    Yes, the WR touch screen stat is the base design for the Mod stat, however, the standard WR stat does not have the v terminal that is required to run the mod (nor the software).
    Doc: Can you tell us (Irascible & me), how the Mod with Mod stat, will behave on a programmed recovery of 10 degres?

    We would be much abliged.

    AM

  11. #37
    Join Date
    Apr 2004
    Posts
    7,680
    Already did... go back..

    It will change the set point by 1 degree every 5 minutes. (5min x 10 degrees=50 minutes) will start 50 minutes before set time, and lets say your set back is 60 and your new temp is 70 at 7:00 am...

    At 6:10, the set point will change to 61, and 6:15 it will go to 62 etc. Whether it shows up on the display as that or not, I guess I never looked however, this will keep the furnace from going into a full fire scenerio, although it may kick up to a higher fire rate as needed.

    It's pretty simple really. With a 1 degree change in 5 minutes, and the ability to run as low as 40%, it will just gradually keep up. I cant tell you the % of fire rate because it willvary with the load that particular morning and that particular system. A 1.0 degree change in the stat will not cause the furnace to automaticly jump to 100%.

  12. #38
    Join Date
    Feb 2007
    Posts
    999
    Quote Originally Posted by docholiday View Post
    Already did... go back..

    It will change the set point by 1 degree every 5 minutes. (5min x 10 degrees=50 minutes) will start 50 minutes before set time, and lets say your set back is 60 and your new temp is 70 at 7:00 am...

    At 6:10, the set point will change to 61, and 6:15 it will go to 62 etc. Whether it shows up on the display as that or not, I guess I never looked however, this will keep the furnace from going into a full fire scenerio, although it may kick up to a higher fire rate as needed.

    It's pretty simple really. With a 1 degree change in 5 minutes, and the ability to run as low as 40%, it will just gradually keep up. I cant tell you the % of fire rate because it willvary with the load that particular morning and that particular system. A 1.0 degree change in the stat will not cause the furnace to automaticly jump to 100%.
    O.K., thanks Doc. The manual wasn't too detailed on the issue of adaptive recovery (whatever?). I just thought that with A.R. disabled, it would behave just like jacking the TS up 4 degrees.

    AM

  13. #39
    Join Date
    Apr 2004
    Posts
    7,680
    Oh yes, if it's turned off, it will

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