A/C gone bad

[DADoES]

 
The F7 fault has not recurred since resetting it on 6/12.

I have not seen the system run on high stage for cooling during normal cycling operation in the frequent 95°F to 99°F weather that has occurred.  It has run briefly on high if the setpoint is manually reduced by 1°F or more.  My June 2022 electric bill is $179.24 for 1,511 kWh.  June 2021 was $227.38 for 1,954 kWh.

 

[supersuds]

That's a nice reduction in electric usage.

This may be a dumb question, but how do you tell what stage the compressor is running in?

 

[DADoES]

 
1) The indoor blower runs faster on high stage.

2) The thermostat has an Equipment Status function which details
     System:  Off, Auto, Cool, Heat, Em Heat
     Heat Pump Stage 1 (Heat):  Off, On
     Heat Pump Stage 2 (Heat):  Off, On
     Aux Heat Stage 1:  Off, On
     Heat Pump Stage 1 (Cool):  Off, On
     Heat Pump Stage 2 (Cool):  Off, On
     Fan:  Idle, On

 

[supersuds]

I see, thanks.

It appears the HVAC company that installed mine gave me a thermostat (Honeywell T4) that does not even have a provision for running a two-stage compressor, i.e., no Y2 terminal. Unless there's something I'm missing!

 

[DADoES]

 
SuperSuds/John, you have two-stage cooling and heating equipment but the thermostat isn't?

 

[supersuds]

I'm afraid so. I've double checked serial numbers: American Standard 4A7A7036A1000 is a two-stage AC. I feel like a chump now.

I assumed that the installers would install a compatible thermostat, but you know what happens when you assume.


https://www.americanstandardair.com...ing/air-conditioners/gold-17-air-conditioner/

 

[DADoES]

 
Staging without a proper thermostat is by the air handler's control board based on run-time ... the 2nd stage triggers after the 1st stage has run x-minutes, whether or not it's really needed.  Perhaps call the installer to change the thermostat to a proper one?.

My thermostat is a Honeywell TH8321WF1001.  It has choices (separate for cool and heat) for 2nd stage switching differential of "comfort" (controlled by thermostat algorithms presumably monitoring both time and temp swing) or by specific temperature swing of 1°F to 3.5°F from the setpoint in 0.5°F increments.  Also separate for auxiliary heat droop, comfort, or 2°F to 15°F in 0.5°F increments ... OR time-based of 30, 45, 60, 75, 90 mins, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16 hrs AFTER 2nd-stage compressor.

 

[mattl]

I have a dual stage furnace, single AC with a Honeywell thermostat. The one thing the dual  stage thermostat does in my system for heat it monitors outside temp and uses that info in calculating how much time  is needed to get the  house up to temp. I'd think it should do the same for cooling.

 

[supersuds]

All very useful, thanks.

 

I will probably call the installer, but am struggling to figure out how this could have been an innocent mistake. And if not should I deal with them at all.

 

[sudsmaster]

John,

If you already paid them for their incomplete work, you should call them to fix their goof.

If they say it's OK, then I'd tell them, OK, I'm going to hire someone else to fix it and send you the bill.

Next step: See you in court.

 

[DADoES]

 
<blockquote>... but am struggling to figure out how this could have been an innocent mistake.</blockquote> What's stated in your equipment quote?  Was there any direct discussion of a two-stage thermostat?  Any discussion or mention by either you or the installer of keeping the original thermostat?  A single-stage thermostat sometimes is used with a two-stage system for "reasons" ... such as keeping the job to a price-point or avoiding the need to run additional thermostat wiring if that presents some challenge.  The system will work although not to the best design-performance.

The T4 line does have a model that's 1C-2H for one-stage/speed heat pumps with one-stage of auxiliary/backup heat, but your stated compressor model 4A7A7036A1000 is a cool-only unit ... maybe the dealer's installer team overlooked that?  Do you have gas for heating?

 

[volsboy1]

John ,

I would call them out  as soon as possible. I would be kinda pissed if in your contract that you paid for , it says

American standard  Model # , Furnace  , with T-stat .  My contract said the model number of each item ,T-stat also both of them.

I have Two  2 stage   American Standard heat pumps upstairs and downstairs , they run all the time on low

one is a twin compressor and the other is a two stage scroll .

 If its a reputable company they should fix it no problems. I had a 10 year parts and labor warranty with mine when it was installed in 2007/08 .

Don't pay a dime don't let them try to charge you for the service call to come out and fix there mistake

and sometimes they would try to charge me. Hoping I would be stupid enough to pay them.

 

 

 

 

[supersuds]

Hi Glenn, yes, I have a two-stage modulating gas furnace also. There was no discussion of keeping the old thermostat since it was an old round Honeywell with a mercury switch and obviously unsuitable.

Thanks for the advice, Wes.

I talked to the owner's son who seemed surprised that I had a problem and insisted that the unit(s) would work just fine in both stages with the existing thermostat, but he said he'd investigate and get back to me. He seems to think I would need a VERY smart thermostat like an Ecobee or Nest, which I'm not thrilled about based on what I've read. I don't think I need an adaptive thermostat, and I don't want everything being reported back to Google, anyway.

We'll see.

 

[DADoES]

 
There surely are other workable thermostats than Nest and Ecobee.  They're trying to upsell you, or they don't know what all is on the market, OR they may be tied to only what a particular supplier carries.

The model I have should work nicely, I don't know the cost of it (search it at online sources), the bill didn't itemize individual component prices.  It has WiFi but connection is *not* required for it to work properly, nor is an outdoor temp sensor (which I don't have).  It does pick up an outdoor temp via WiFi (based on an unstated reference per the ZIP code if that info is entered) but again, it *does not* require an outdoor temp reference for staging control.

The glitch may be if your system is a high-tech communicating control system that requires specific thermostats to interface properly, but that seems unlikely.

 

[mattl]

My Honeywell has dual stage capability, no need for a Nest or such. Depending on your provider my Utility company is often offering free t'stats if they are programmable - no need to program them.

 

[whitewhiskers]

Thermostats

I have an Emerson 1F95-1277 that's been great. It's called "Big Blue Universal 3/2". It can work with many different HVAC configurations. It has 27 different settings, you go thru it all in the installer/config menu. It has a nice blue display, very easy to read, no WiFi or other nonsense. You can even program in reminders to change air filters. I set up programs for the winter, but in the summer I prefer to use it manually, adjusting temp settings for how I want the house cooled.

It's somewhat pricey, around $180. Just my review and recommendation.

https://climate.emerson.com/en-us/shop/1/white-rodgers-sku-01f95-1277

 

[volsboy1]

He is lying John , I am sorry to say any two stage American Standard Air/ heat pump will  need the

two stage T-Stat. That switch uncovers the ports in the scroll which makes it run at 67%  and then reduces the air flow .

The let me talk to Dad is basically let me blow you off or screw you talk . Not even a hug after.

I would call and keep calling and then I would drive up there and demand it.

Those T-stats are not cheap , I have never seen a contractor change out a system and not put in there own unless it was requested.

I would drive them NUTS ...     The Air will work but what was the point with installing a dual stage if you cant use it. It's like buying a car and they did not give you the keys .

 

[DADoES]

 
Electric usage for Aug 2021 when the old system went kablooey was 2,488 kWh.

Aug 2022 is 1,381 kWh.  The setpoint has been a raised a bit for several couple-days periods when I've been out-of-the-house for attending dad's extended hospital stay, but the higher setpoint is what I'd been running as normal a year ago so the effect isn't much.

Electric rate is up a bit from last year but the bill is still $100.76 less than Aug 2021 and there's a (biennial) capital credit refund applied atop that.  Yay!

 

[DADoES]

 
Latest arctic blast.  Outdoor temp is currently 25°F, predicted low of 20°F or 19°F.  The Trane XR17 heat pump is maintaining the indoor setpoint of 69°F, cycling between low & high stage without triggering the auxiliary.  Wall thermometer in a bedroom reads 69.7°F.  I have the thermostat programmed for a 3°F droop on auxiliary to provide an obvious indication if it's needed.  Stage 2 is set for "comfort" vs. a °F-droop or time-period.  And "finish on high stage" = no, which means it'll drop back to low stage when the room temp is within the "comfort" algorithm's satisfaction (instead of staying on high stage to attain the setpoint and shutting off), which makes for a more steady room temp curve.

Also, one of the auxiliary breakers (purposely) is turned off.

 

[tomturbomatic]

YAY! Now all you have to do is maintain electrical service.
Merry Christmas.
Tom

 

[DADoES]

 
19.7°F on the patio.  17.7°F at someone's personal weather station a bit north outside town linked on WeatherUnderground, 16.9°F on one at south end of town, 17.4°F in town, regional airport several miles east says N/A.

Bedroom of reference 69.6°F.