A/C gone bad

[combo52]

Yay New Train Heat-Pump

Looks Good, 

 

Question Glenn how is an A coil mounted in a horizontal air handler, I have always seen A coils in up-flow or down-flow air handlers.

 

It also looks like you might want to put more insulation in the attic and maybe even some on the plenum attached to the air-handler. I think that almost everywhere you should have at least R30 in attics.

 

John L.

 

[DADoES]

 
John, the A-coil and air handler are convertible to upflow, downflow, horizontal left flow, or horizontal right flow.

I had a media air cleaner (Honeywell F100F2025, 20x25x4) added (installed today) so I can now see the coil through the filter slot.

 

[DADoES]

 
Current outdoor is 32°F to 35°F depending on the reference.  Misty rain.  Setpoint 68°F maintaining on low stage.  Cycling earlier in the day, increasing to continuously running now for probably more than 2 hrs.

Thermostat configured at "comfort" to hold temp within 1°F of the setpoint using low & high compressor stages per algorithms that monitor the indoor temp curve.  It has not yet engaged high stage AFAIK for any heating since the 1/4/22 install date.  Be interesting to see if it'll upstage soon.

Auxiliary staging choices of
   A) "comfort" on aformentioned algorithms
   B) specific °F setpoint droop in 0.5°F steps
   C) specific upstage run-time (30, 45, 60, 75, 90 mins -- 2, 3, 4, 5, 6, 8, 10, 12, 14, 16 hrs)
   D) combination of B and C.
Currently set at 3°F droop, which will present obvious indication when it's needed, and whether adjustment of the setting is needed.

Predicted low of 24°F tomorrow morn.

 

[DADoES]

 
High-stage compressor engaged a couple mins ago.

 

[DADoES]

 
LOL, it didn't stay on high very long, already cut back to low. 

 

[DADoES]

What would you do?

 
I removed the service panel on the compressor unit several days ago for a look-see at what components are in there.  Found the tech sheets, scanned them to .pdfs for future reference, put them back into the storage envelope.

I noticed the red light on the EEV (electronic expansion valve) board flashing a sequence, so looked for the code on the tech sheet.

Code 7 -- Valve is responding but system is not performing properly (Low charge or restriction).

Codes 1 to 5 reset on a power cycle.  Codes 7 to 10 require a specific reset sequence so may be flashing history instead of an active code.  I thought maybe the code triggered during installation on the initial run while they got the refrigerant charge settled so I enacted the reset procedure, it stopped flashing.

Checked again a few days later after the system had run a few cycles, Code 7 is flashing again.

Should I bring it to the contractor's attention (without mentioning that I had done the reset)?  A homeowner isn't supposed to be poking into the mechanism and I'm leery of presenting as a "problem customer" two months into the installation ... but it needs to be checked if there is a problem.

 

[repairguy]

Absolutely

 

[combo52]

Flashing red fault light

Hi Glenn, I would definitely call the company that installed the system, this is your system you’re allowed to take it apart examine it all you like the only way they can void warranties is if you actually caused some damage.

 

Just explain that you were inspecting your nice new system when you opened up the panel you saw the flashing red light you looked it up and found that it may be a restriction or low charge and ask that have them check it out.

 

John L

 

[DADoES]

 
Follow-up:  There was a "tiny" leak at one of the refrigerant charging ports.  Enough had leaked out to trigger the fault.  Fortunate that I looked there and caught the code.  I am expecting it to run for long periods on low speed as summer weather progresses so wouldn't have noticed a performance impact until it couldn't keep up on high speed, or safety sensors shut it down completely.

 

[repairguy]

I would consider that a fairly large leak if enough refrigerant leaked out in a 3 month timeframe to trigger a low pressure switch code. I’m glad you called and got it taken care of.

 

[DADoES]

 
I checked this afternoon, it's flashing the F7 code again, or still.  I didn't check immediately after the repair two months ago so I suppose it's possible they didn't clear it then.  I cleared it now to watch for recurrence ...

 

[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/products/heating-and-cooling/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.