Geome

I have just installed a new Honeywell Prestige thermostat. With all the experience that you have expressed here, I have a a question for you.

I noticed at first startup the fan would run for about 5 minutes at a call for heat even though the compressor was not starting up right away. I understand that there is a timeout for the compressor at power up on the heat pump control board. I do not have the thermostat set for a time delay for that reason. The net result is 5 min of cool air blowing. I would rather have the fan start when the compressor does.

I believe when the thermostat is setup as heatpump the thermostat calls for compressor Y and fan G with no other option for fan control available. I also believe the heatpump control is smart enough to control the fan in conjunction with compressor operation.

I could setup the thermostat as conventional and select the option - (gas/oil) the furnace controls the fan. Doing this however, would lose alot of heatpump options (ie. 3rd stage heat, emergency heat, aux control options). Also the heatpump option usually allows wider temp differentials than conventional systems. No

I could disconnect the fan (G) wire but would lose the recirculation feature and fan control at the thermostat. No

Maybe this 5 min cool air thing only happens after power is interupted and will not be a problem in normal use (faster compressor startups). After all it is ALL about control.

Anyway the question is. Is there any way to allow the heatpump control board to control the fan while the thermostat is setup as a heat pump?

I thought you might like to check out comments on the new draft version of Energy Star  Thermostat spec revisions.
http://www.energystar.gov/index.cfm?c=revisions.thermostats_spec
We thought we in control of our thermostats. No, Honewell is.

I have White-Rogers thermostats who may be in bed with Honeywell. Mine has a feature called "Compressor Lockout" of "CL" on the menu. If turned "on" the thermostat calls for fan 5 minutes before Y1. I've turned it off.

Hope this helps.

If memory serves the back programing of the stat is in plain english you need the security code but I dont think thats your solution ( hint its writen on the stat )
If the system is zoned a pre-purge may be sourced there (ie from the zone board)
also before any adjustments are made I would 100% confirm that there isnt a 30sec start time diff. which is a good thing considering ecm motors ramp up , in combonation with time for the coil to warm and time to purge the cool air that has been sitting in the ducts out. if you find that or something close is the case I would leave well enough alone . If not deselecting the pre purge option if available in the back programing of either the stat , the zone board or both. You could get extreme and pick up a delay on make TDR and break R but I wouldnt

Hi G.O. Joe. Just came back from a road trip. Sorry for the delay in replying. Will take me a few days to get caught up. Keep in mind that I'm not an expert (just a homeowner) and don't know anything about zoned control and the control boards of heat pumps other than a limited amount about our WF Envision units. But I would be happy to tell you what I know.

With our 2 stage water to air Envision units, all within 15 seconds (if I read the manual correctly) the blower starts on low speed and changes to medium speed and the compressor starts in 1st stage. I have seen no settings on the Prestige that can alter this. I have seen options to continue the fan for a period of time AFTER the compressor shuts off. I don't use this feature since our Envision units continue the fan for 30 seconds after the compressor turns off and I am happy with this.

Our Envision units have a built in 4 minute delay from the time the compressor turns off until the compressor can turn on again. In the Prestige, there is an installer setting called "Minimum Compressor Off Time". I have this set to 5 minutes. This gives our compressor an additional 1 minute off for a total of 5 minutes instead of 4 minutes. I just like 5 instead of 4 minutes to help protect the compressor, but the additional 1 minute may be unnecessary. If I bump up the thermostat during that time or if there is a normal call for heat (or AC), the thermostat says "Waiting for Equipment". During this time, our fan doesn't run. I haven't seen a Prestige option for run or don't run the fan during this wait time. It may be an option on your equipment. The experts could better advise you on this.

The Prestige does have a Compressor Lockout, but that isn't the feature your're looking for. That setting is used in conjunction with an outdoor temperature sensor and I haven't found any reason to use this feature with a geothermal heat pump with aux heat strips. I believe this feature can be used if a gas furnace is used with a heat pump. With this feature, you set the outdoor temperature at which you want to engage the furnace and lockout the heat pump (so the furnace won't damage the heat pump).

The code to get into the installer setup is the 4 digit date code of the thermostat. The quickest way to find this is to go to Menu, Equipment Status, then scroll to the bottom of the page and look for "Date Code".

It might help the installers help you eliminate the fan running during the 5 minute lockout time if you tell them the make and model of your heat pump, describe your system (water to air, radiant heat, etc.) and describe zoning equipment (if any).

G.O. Joe - unrelated to your original post, but related to Prestige...
If you use AC, remind me in the spring to go over the "Dehumidify with AC" feature of the thermostat. There are a lot of options that can be tweaked in there, including the aggressiveness of the AC.

Geome

Thanks for your reply. I would be very interested in discussing dehumidification options.

It turns out the Climatemaster 27 control board does need a fan G signal to operate the compressor. The only time I had to wait a period of time for the compressor to start was after I powered the unit off and back on at the breaker. In normal operation the compressor starts in short order.

You said you have the thermostat set to 5 min minimum off time. Does that timing run concurrent with the unit time out or in addition? Maybe if I match the unit time out with the thermostat time out the fan won't come on while the compressor is in a time out?

I mentioned Energy Star specifications in discussion for thermostats in a previous post. From what I understand the proposed specs included thermostats for geo systems with 3 stage heating, 2 stage cooling with better ways to for the homeowner to control Aux heat. Honeywell said that it was such a small segment of the market that it should not be included in the specification.

The min off time runs concurrent, so with my equipment and settings there is a 5 minute minimum total wait between compressor cycles.

I'm getting a little confused about the fan issue. If your compressor starts right away, then when does the fan run without the compressor? Is your fan set to "on", "automatic" or "circulate"? In the Prestige, you can set this option in each program schedule.

geome

The 5 min unheated fan run was only happening after I turned the unit off at the breaker or turned the unit off at the tstat to make setup changes. I have now changed my setting on the Prestige to a 5min minimum compressor off time to match the compressor timeout and now the fan waits to come on until the compressor is on.

Before I didn't see the logic in allowing a timeout at the thermostat when the HP already had one. The tstat called for the fan and compressor so the fan would come on immediately while the compressor had to wait on its own timeout. Now I know.

One of the reasons I bought the Prestige was its ability to provide dehumidifcation. The ClimateMaster I have it mated to has a DH function that is enabled by the stat that will lower the fan speed in cooling to provide better DH. I have read about the Prestige option to DH by cooling upto 3 degrees below setpoint. I will have to see what combination works.

Thanks for your help!