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Old 01-20-2010, 01:02 PM   #1
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White Rodgers 1F95-1291 Tstat Dual Fuel problem


I've had trouble getting my original installer to address an issue I am having, operationally, with the Big Blue Thermostat.

Though my system is a single stage heat pump with my original 80% gas fire furnace (hybrid), and the system has an outdoor sensor attached, I am unable to lockout the gas furnace based on setting the lockout temp within the thermostat setup.

It seems that regardless of the setup, the gas furnace comes on after the heat pump has run for a while without being able to achieve the setpoint. I thought the idea of a lockout would simply be to allow the heat pump to run, even if the thermostat was not happy with the rate of heatup.

Specifically, with outside temperature above 45 degrees, and the lockout temp set at 35 degrees, the system begins heating the house in the morning from perhaps 65 with the setpoint at 68 degrees. The gas fire comes on after the heat pump has run for a while. I am not sure how long the HP ran, but my impression is that its either on a timer controlled by the tstat or the warming rate wasn't enough, so the tstat brings on the gas fire.

Aren't you supposed to be able to use this tstat to lockout the gas fire? Or does it simply ignore that lockout if the home isn't heating quickly enough or has not reached set point in X amount of time?? I can not find anything in the user manual which suggests that the gas backup will come on REGARDLESS of the lockout setting. So, I am looking for help here.

I suspect that my installers may have simply miswired something.

Mike

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Old 09-28-2010, 12:02 PM   #2
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White Rodgers 1F95-1291 Tstat Dual Fuel problem


OK

I have the same problems with a different thermostat and and interested in purchasing this thermostat to fix this exact problem....

Please let me know if this helps....

Under your set-up features (30)

30. Select Auxiliary Off (AO) – Select the temperature that will inhibit the auxiliary heating stage. As long as the outdoor temperature is above the selected temperature, the
auxiliary heat will not turn on. The default setting is 60,
but can be set in the range of 35 to 80.



29. Select Dual Fuel Feature Using Outdoor Sensor (dF)
– This feature is applicable only in heat pump modes and
with an outdoor sensor installed and enabled in step 27.
When selected ON, the thermostat will use the outdoor
sensor temperature to determine when to switch to gas
heat and shut down the compressor.

Last but not least there is also an adjustment where you can tune the difference between the primary heat and the secondary heat.

28. Select Dual Fuel Feature With No Outdoor Sensor
(dF) – This feature is applicable only in heat pump modes
and with no outdoor sensor. When selected ON, the
thermostat will use software logic to determine when to
switch to gas heat and shut down the compressor.
Select DF setting (dF) – With DF selected On and no
outdoor sensor, select the dF setting from 01-09. Factory
default is 05. The dF setting infl uences when second
stage comes on. The factory default creates a separation
of approximately 1oF between stages. Increasing the setting
decreases the separation between stages. Decreasing
the value increases stage separation. This adjustment
allows a small change in the operation of your heat
pump system versus your auxiliary system relative to the
thermostat adjustment. The higher the number the sooner
the auxiliary stage energizes. The lower the number the
longer period of time before auxiliary is energized.
Note: This setting is not minutes or degrees. It is numeric
setting that will infl uence the internal thermostat

Try lowering this figure from default of 5 slowly down to 1 to see if it help limit the use of GAS.

I like the last option best as it will allow you to set the temperature differential so that the gas to kick in when the HP can't heat the home to the desired temperature when the difference in house temp is greater than a sertain setpoint..

Of special interest make sure your primary HP is set to FA (I.E. It will try to keep the temperature within approc .75 deg of setpoint) and the GAS should be set to SL (1.7 deg range)

Also, to prevent the heat (GAS) from cycling because of your morning raise due to lowering at night, program in 2 different cycles to heat up in the morning about 2 hours appart raising the temp (Approx 2 deg F) each time....This will create a graduated temp rise and should eliminate the gas from coming on unless absolutely required to maintain your normal house temp....

Also make sure the setting for EMR Is ON

7.
Energy Management Recovery (EMR) – (this step is
skipped if confi gured as non-programmable). When set
to "On" causes the thermostat to start heating or cooling
early to make the building temperature reach the program
setpoint at the time you specify.

Example:
The heating program is 65F at night and 70
at 7 AM. If the building temperature is 65F, the difference
is 5F. Allowing 5 minutes per F rise, the thermostat setpoint
will change to 70 at 6:35 AM. Cooling allows more

time per F, because it takes longer to reach temperature.

Please let me know if/what works as I want to purchase this same unit to control the same....

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Last edited by kflack; 09-28-2010 at 12:15 PM.
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Old 09-28-2010, 01:09 PM   #3
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White Rodgers 1F95-1291 Tstat Dual Fuel problem


I've tried all of the things you've stated, and the only one that has worked is the very last where you use up two of your cycles to increase by 2 degrees each time. The house typically gets down to 64 at worst (unless we really have a cold cold night), so the fix that I finally came up with last year was to molly coddle the system by having it come on and make up 2 degrees per hour. So, since I want 68 degrees by 7:30am, I set for EMR to have 66 degrees by 6:30, then 68 degrees by 7:30am. So far this has been the only way to work around the TSTAT. I can not lockout the gas heat using any methods. I did think of simply turning off the outside sensor with 29, but this also eliminates the reading so that solution was tossed aside because I do like knowing what the temperature is.

Also, I have two identical White/Rodgers (Emerson) tstats and neither locks out as advertised. So, I have simply used up the 2 cycles (our of 4 allowed) to run this up as you had indicated. I have to hand it to you for coming up with that. As I played with this thing all last winter attempting to figure out why I couldn't lock out the gas backup until finally coming up with that work around.

I was also dealing with a bad reversing valve on both units at the same time due to a factory recall which took me a long time to get serviced, so that added to the problem because once in defrost the units would stop heating and, naturally the gas backup would eventually come on.

Now that I think of it, I am not sure that I ever tested the lockout AFTER getting that problem serviced. Maybe the Tstat lost communication with the outdoor unit when it got stuck in defrost and this is what caused the gas heat to perhaps OVERRIDE the Tstat and come on. I'll try again using the lockout this year and let you know what happens now that all the equipment is working properly.

Thanks for the response.
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Old 09-28-2010, 02:06 PM   #4
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White Rodgers 1F95-1291 Tstat Dual Fuel problem


Re Defrost....

Interestingly enough, my defrost is hardwired to the furnace to W1, which immediately activates the furnace during defrost cycles. i.E. This signal never goes to the thermostat.

This activation allows the house not to get cooler while the Heat Pump (Valve reverses) by itself as it is performing a defrost cycle.The cycling of the blower during this time is also very important as it is used to heat up the Heat Pump (Defrost).

To minimize the use of gas (Furnace) during this operation you can, if you can handle the temperature drop in the house, wire the defrost signal from the Heat Pump to the Blower instead of the W1 (Furnace ON)....Will be trying it this winter for myself to see how much savings its results in....It will take longer to defrost, and be cooler during the cycle but a $ saved is a $ earned.

Oh by the way....Another way to try to minimize the aux coming on it to make sure that the return vents in your basement as turned off (If you don't heat much down there) Reason being is when you have your first heat in the morning, it actually cools your house by pulling cold aire from the basement upstairs. This makes it even more difficult for the HP to heat the air within its normal time parameters, and may cause the aux to come on as well...

Last edited by kflack; 09-28-2010 at 02:08 PM.
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Old 09-28-2010, 04:09 PM   #5
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White Rodgers 1F95-1291 Tstat Dual Fuel problem


My installers never hooked up the feedback line so that the furnace would come on during defrost. I think I am glad too, because in our other house which has a Carrier Infinity in it, the gas fire is limited to LOW stage during defrost so as not to create too much heat in the coil which wants to get very cold so the outside coil gets very hot so it can defrost. This situation still allowed the house to actually cool off during the defrost.

In this house, which has 2 units (one for each of two floors - no basement), even without the gas fire (one stage HIGH) coming on, the defrost takes place quickly enough that the tstat remains steady. So, I have the systems set on 60 minute defrost cycles (if I remember correctly) so defrost hasn't been too much of a problem since typical winter temps are above 40 here.

Another note on the "smarter" Carrier Infinity versus the Goodman Heat pumps with backup 15 year old Carrier Gas furnaces (which are what is in this house) - When I used the Carrier Infinity the way it was factory programmed, I noticed that once the heat pump gives up and the system would fall back to gas backup (ie during morning start up on cold days), the gas furnace would simply continues to cycle low, med, high, med, low, med, high, etc., and never give the heatpump a chance to come on because the system would never shut off.

So, I had to override the gas fire to ALWAYS HIGH so that when it did fail over to it, it would run until it toasted the house and then shut itself off, so that on the next start up the heat pump would come back on. This allowed for warm ups in the morning with gas then running the heat pump to maintain the constant temperature.

My conclusion is that even though these systems are supposed to be brilliant, you have to override them to get the best economy in the Pacific Northwest. They seem more geared for the east coast where gas prices are much cheaper than electric - not true here. The carrier rep even told me "Well, that's what you want" when I told him the gas fire wouldn't ever shut down once it was called. It's not what we want here - we have hydro electic power here and gas is over $1.20/therm.
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Old 09-28-2010, 06:07 PM   #6
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White Rodgers 1F95-1291 Tstat Dual Fuel problem


Sounds like your Infinity was set to comfort mode.

Just needed to set it to economy to stop the cycling.
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Old 02-04-2011, 02:07 PM   #7
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White Rodgers 1F95-1291 Tstat Dual Fuel problem


Quote:
Originally Posted by mgroves View Post
I've had trouble getting my original installer to address an issue I am having, operationally, with the Big Blue Thermostat.

Though my system is a single stage heat pump with my original 80% gas fire furnace (hybrid), and the system has an outdoor sensor attached, I am unable to lockout the gas furnace based on setting the lockout temp within the thermostat setup.

It seems that regardless of the setup, the gas furnace comes on after the heat pump has run for a while without being able to achieve the setpoint. I thought the idea of a lockout would simply be to allow the heat pump to run, even if the thermostat was not happy with the rate of heatup.

Specifically, with outside temperature above 45 degrees, and the lockout temp set at 35 degrees, the system begins heating the house in the morning from perhaps 65 with the setpoint at 68 degrees. The gas fire comes on after the heat pump has run for a while. I am not sure how long the HP ran, but my impression is that its either on a timer controlled by the tstat or the warming rate wasn't enough, so the tstat brings on the gas fire.

Aren't you supposed to be able to use this tstat to lockout the gas fire? Or does it simply ignore that lockout if the home isn't heating quickly enough or has not reached set point in X amount of time?? I can not find anything in the user manual which suggests that the gas backup will come on REGARDLESS of the lockout setting. So, I am looking for help here.

I suspect that my installers may have simply miswired something.

Mike
The tstats are designed to engage auxiliary heat if the temperature is not satisfied within a certain time limit. I do not believe one can override that, or change the time setting.
The lock-out is to prevent the heat pump from engaging at the set temperature; not to lock-out the auxiliary. This is primarily for gas auxiliary as you do not want the heat pump and the gas auxiliary running at the same time. With electric auxiliary, it is ok for both to be running. This is because the indoor coil is mounted after the burner with gas, but before the electric strips with electric. Mounting the coil before the burner (gas) is not advisable as the moist air is not good for things. There is no burner or heat exchanger with electric and it doesn't matter.
With electric, the heat pump acts as a pre-heater due to the fact that the indoor coil is before the heat strips. If it is sufficient, all's well. If not, the electric auxiliary cuts in and then all's well.
Exact scenario I have in the Pacific Northwest and works well. It's never cold enough for the heat pump not to be generating at least some heat, which means that the auxiliary just has to do less. Very difficult to set up if not already as the necessary wiring for electric auxiliary is not cheap or easy, although the actual furnace is much less expensive.
At least that is how I understand it, not being an expert. If you have found something different, please let us know.
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Old 02-04-2011, 04:43 PM   #8
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White Rodgers 1F95-1291 Tstat Dual Fuel problem


The user's manual clearly describes a feature which serves to control "hybrid systems" which is what I have (heat pump w/gas backup), and there are two settings governing switchover control. One is as you've stated - a low temperature lockout - whereby the heat pump won't come on and instead the heat will be by gas furnace only. The other setting clearly describes a temperature at which the gas furnace will be locked out, and in that case, I am now told by Emerson that the user's guide is faultly written. Emerson says that in order to make the temperature back if the heat pump hasn't done its job then rather than continue to run the heat pump the tstat will call for the gas fire to finish the cycle. And this has been my experience. So, I wish they would be honest in what they've written.

Mike
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Old 02-05-2011, 12:22 AM   #9
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White Rodgers 1F95-1291 Tstat Dual Fuel problem


Ha-ha, I know what you mean. There does not seem to be a standard, although one would think there would be, and everybody uses different terminology and interchangeably. Add in the mistakes in just about every HVAC manual I've encountered and it's enough to make one think they are on a different planet.
On top of it, experts seem to have as much trouble deciphering as the ordinary lay-person; I've read numerous reports of customers having had their equipment improperly set-up by those in the trade. It's really just not mainstream DIY stuff, at least not yet.
That's quite the serious mistake in documentation though and I don't envy you.
How much hair did you lose?
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Old 02-05-2011, 05:23 AM   #10
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White Rodgers 1F95-1291 Tstat Dual Fuel problem


Get a Honeywell thermostat(TH8320,8321, or YTH9421) and you can lock out the gas furnace. Even if the heat pump is running for 12 hours and the indoor temp is 6 degrees below set temp, they won't bring on the gas furnace. The YTH9421 does have an upstage timer you can set, if you want to make sure your house reaches temp(or doesn't get cold enough to freeze pipes) in case the heat pump were to fail at a temp above the gas furnaces lock out temp.
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Old 02-05-2011, 12:39 PM   #11
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Quote:
Originally Posted by beenthere View Post
Get a Honeywell thermostat(TH8320,8321, or YTH9421) and you can lock out the gas furnace. Even if the heat pump is running for 12 hours and the indoor temp is 6 degrees below set temp, they won't bring on the gas furnace. The YTH9421 does have an upstage timer you can set, if you want to make sure your house reaches temp(or doesn't get cold enough to freeze pipes) in case the heat pump were to fail at a temp above the gas furnaces lock out temp.
Thanks. I just ordered a YTH9421, somewhat cautiously, but now feel a little better. It's a little difficult to determine that it in fact does what you want it to do. I was told to get the 8321, which I did, and then discovered it won't do 2 stages of auxiliary heat. The 9421 does (I think...I hope, verification please) and hence ordered it. Same thing happened to my brother in the lower mainland and to this day the installer insists he is getting 2 stage auxiliary, which I find hard to believe with the 8321.
Seems like the 9421 is the one to get for max flexibility, even if for down the road.
Separate question, if you have a comment. Is it better (less expensive) to run less strips (electric auxiliary) longer or more strips shorter?
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Old 02-05-2011, 10:00 PM   #12
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White Rodgers 1F95-1291 Tstat Dual Fuel problem


The YTH9421 will control 2 stages of gas heat, or of electric aux heat.

It is generally best to only bring in the amount of electric aux you need to supplement the heat pump. So it has a long run time. Bringing on all the electric aux heat when only half as much is really needed uses more electric then letting the heat pump have long run times.

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