American Standard AC with York furnace?

[CathyAnn]

My tech is recommending the switch as he prefers AS over York for cooling.

Another company we like prefers Carrier.....

Thoughts and suggestions welcome.

[beenthere]

No real problem.

[BaldLoonie]

As long as the indoor coil is matched to the A/C and there is proper airflow, no problem. Only issue would be efficiency ratings that require a specific ECM blower inside, usually above 14 SEER.

[CathyAnn]

Thanks....another question.

Since we have a two-stage furnace, does the AC need to be two-stage, as well?

If so, and we go with two-stage, does it help humidity issues more than single stage?

[BaldLoonie]

If you have a variable speed furnace, you CAN use a 2 stage A/C. With standard blower, even if 2 stage gas, really not the optimum way to utilize the advantages of a 2 stage A/C.

[CathyAnn]

Thanks, BL.

We do have a two stage blower in the furnace.

Would we benefit, particularly lowering humidity wise, going with two stage AC?

[BaldLoonie]

Is it a variable speed blower? Know the model # of the furnace?

[amd]

With standard blower, even if 2 stage gas, really not the optimum way to utilize the advantages of a 2 stage A/C.

Can't it be done with an additional relay?

[beenthere]

Can't it be done with an additional relay?
Usually not. Can't control the blower speed enough.

Fanhandler and ICM both make a control that can be added. But, you still don't get the same operation as a VS blower.
You either loose some A/C efficiency, or humidity control with both of them.

[Airmechanical]

any "2 stage" blower these days IS most likely a variable speed motor

now, if we only knew the model and serial number



.

[CathyAnn]

The furnace is a York Affinity PVC9CONUP11 92.02 two-stage (left old condenser coil)

White Rogers IF85-275 programmable thermostat.

The old AC is a 15 year old Concept (still looking for info)-don't think I have the manual anymore.....believe it is 4 ton...2900 sq ft house

[beenthere]

That furnace will work fine with a 2 stage A/C. Its a VS blower.

[CathyAnn]

Thanks!

But............does a two stage eliminate MORE humidity?

[beenthere]

Due to the longer run time of first stage, yes.

[CathyAnn]

Thanks again, BT,

While I realize it is relative to the outdoor temp, what length(s) of run times in "low" and "high" should I expect?

With our furnace, it rarely goes into "high" unless it is VERY cold out or we crank the TS up too fast.

[beenthere]

Thats it. No set time. It varies for each home. And the ambient conditions of the day.
Along with how close the unit is sized to the homes load at design conditions.

Next, which thermostat is controlling it will also vary the run time.

A Honeywell vision Pro or IAQ will run the unit 10 on 10 off at 50% of the design load conditions.

As the outdoor temp increases. The on time will increase, and the off time decreases.

[CathyAnn]

White Rogers IF85-275 programmable thermostat