Thermostatic Controls - York 2 stage DFHP with VisionPro IAQ

Just replaced our old 10 SEER split AC/furnace with a 4-ton, 2 stage, York Affinity HP and VS modulating furnace. Also insisted on a HW VisionPro IAQ Tstat. The tstat is providing formidable for me and the contractor who hasn't put in an IAQ or this high a level of DFHP before.

We are having a lot of run time in stage 1 and having a problem getting the system to bring the RH below 55% without a lot of running or even with a lot of running. The house is pretty tight per the blower door results which says it does only .33 air changes per hour.

I know that he hasn't wired the furnace DHUM terminal.

Can anybody advise on the following questions:

1) How does one get some swing in the temp to reduce run time? The old system/tstat did +- 1 degree. So if I set it on 78 it turned on at 79 and off at 77. The IAQ seems to have a fraction of a degree tolerance and is running a lot even though the temp reading neither goes up or down and is at temp setting.

2) How does one use the stage 1 and 2 cycles per hour to control humidity and run time? The manuals suggest values but give no rational or guidance on how to address humidity or run time.

3) Exactly how does the IAQ control the blower speed to dehumidify and which settings control this?

Just replaced our old 10 SEER split AC/furnace with a 4-ton,
How big is the home?


I know that he hasn't wired the furnace DHUM terminal.
That maybe part of the problem. I would suggest getting this wired up. You add a jumper wire from one of the R's on the EIM to DHUM1. Then you hook up a wire on furnace DHUM and same color to DEHUM2 on the EIM. Then we may need set the dip switch. Also, do you know what the blower is set up to on the dip switches?

What is the model # on your furnace?


1) How does one get some swing in the temp to reduce run time?
There is not "swing" on Honeywell, could change #690. What is that set to now? Also, what is 220 and 230 set to?


2) How does one use the stage 1 and 2 cycles per hour to control humidity and run time?
With the CPH setting, it's numbers of time the system run at 50% load. The more cooling load is needed, it will run longer, and when the load gets I think 90% load, then it will go to the next stage.


3) Exactly how does the IAQ control the blower speed to dehumidify and which settings control this?
If the humidity is high, the IAQ will tell the DHUM on the furnace to slow the blower down, that will allow the coil to become colder, and will help remove the humidity.

IAQ setting #379 to 1.

Jay, thank you very much for the info. Here is the data you requested and yet more questions: How big is the home?

The house is ~3500-3700 sqft with 5000 sqft under roof including garage and partial basement with no heated space there. The house has partially underground walk out at lower living space/garage level. HVAC in garage with no ducts in attic. Garage stays pretty moderate in summer and winter.

That maybe part of the problem. I would suggest getting this wired up. You add a jumper wire from one of the R's on the EIM to DHUM1. Then you hook up a wire on furnace DHUM and same color to DEHUM2 on the EIM. Then we may need set the dip switch. Also, do you know what the blower is set up to on the dip switches?

Here are the furnace blower speed numbers (these the dip switches you want?):

Stage 2: 1670 CFM

Stage 1: 1085 CFM

Also have Fan On/Circulating set to 40% * 2100 CFM Blower Capacity = 840 CFM

What is the model # on your furnace?

YP8C100C20MP - York 100k Btu, VS, modulating furnace

There is not "swing" on Honeywell, could change #690. What is that set to now? Also, what is 220 and 230 set to?

220 CPH for 1st stage cooling = 3,

230 CPH for 2nd stage cooling = 2,

690 Temp Control Cool = 3 More Aggressive temp control.

Runs a lot in stage 1 except if I mess with the temp setting or the RH setting sometimes. If the IAQ has no swing, do you know what its +- temp tolerance is?:confused: Must be a fraction of a degree, right?

With the CPH setting, it's numbers of time the system run at 50% load. The more cooling load is needed, it will run longer, and when the load gets I think 90% load, then it will go to the next stage.

Still not following in regards to setting CPH for stage 1 and stage 2. Could you also define 50% load in terms this HVAC non-wannabe can understand?:confused:

If the humidity is high, the IAQ will tell the DHUM on the furnace to slow the blower down, that will allow the coil to become colder, and will help remove the humidity. IAQ setting #379 to 1.

379 Dehumidification Control = 1 Dehumidify with Air Conditioning.

When the IAQ tells the furnace to slow the blower is that to an exact or percentage of CFM setting in the dip switches or does it keep slowing it using some algorithm?:confused:

PS: We love Rochester Minn and the Italian restaurant there. Stop whenever we can on the way up through Wisconsin to the hometown in the Michigan UP.

"That maybe part of the problem. I would suggest getting this wired up. You add a jumper wire from one of the R's on the EIM to DHUM1. Then you hook up a wire on furnace DHUM and same color to DEHUM2 on the EIM."

Did a quick check of the terminals on the cover of the EIM. Can't find any DHUM1 or DEHUM2 (DHUM2). Did find a block named DHM with a 1 and 2 terminal. Assume this is what you are referring to, correct?

Repeating question from previous post:

When the IAQ tells the furnace to slow the blower is that to an exact or percentage of CFM setting in the dip switches or does it keep slowing it using some algorithm? :confused:

I'm making it short here, and sorry for not getting to you soon.. There's been a death on my other half's family.


yes. DHM1 and 2 is what i was talking about.

When you set the humidistat to 45%, and if the humidity is above that set point the blower will slow down. (not sure what yours does yet with out looking at the manual, mine slows down to 80% speed of my cooling CFM)

And if the setup menu set to "over cool" and the room humidity is 5% over set point, it will force the A/C to run to try get the humidity lower, and it may cool 3˚ below set point. (Don't happen often on mine.. Just on cloudy rainy days)

I'll get back to you next week in more detailed answers to your earlier questions.

Contractor was in today and wired IAQ EIM red (power) to DHM 1 and EIM DHM 2 to furnace DEHUM.

Also moved the furnace control board HUMIDISTAT setting to "Yes". Manual stated this is to be done "when using a external humidistat". Is the IAQ considered "an external humidistat"?

Per HW he reduced the CPH for stage 1 to 2 and stage 2 to 2 to get longer run times. Sound about right?

Also moved the furnace control board HUMIDISTAT setting to "Yes". Manual stated this is to be done "when using a external humidistat". Is the IAQ considered "an external humidistat"?
Yes.

Per HW he reduced the CPH for stage 1 to 2 and stage 2 to 2 to get longer run times. Sound about right?
Yeah that's fine.. I have mine set to 1.