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Soft start for my new replacement HVAC Carrier system

LadyLion

Member
Jul 30, 2020
78
20
SF North Bay
I am replacing my 14 year old Carrier Performance system with a new A/C and furnace. The AC is a
Performance series 17 SEER 2-stage 5-Ton AC unit.
My previous Carrier AC was a 4-Ton, single stage.
Tesla installed a soft start in September 2020 with my new Tesla 36 kw solar and 3 PWs.
My question is whether I should have the installers move the soft start I have to the new AC?
Does the new higher tonnage ( 5 tons vs 4 tons currently) matter, i.e. will the soft start be undersized?
Is a soft start needed with a “two-stage “ AC unit?
Thank you for your help in advance.
 

Vines

Active Member
Jul 20, 2018
2,182
2,665
Silicon Valley, CA
2 Stage compressors will benefit from the soft start technology. However first check if your manufacturer has a factory sure start part available. Some do, and its best to use the factory part when possible.

The Sure Start does need to be sized to the load so if you do move it to the new AC make sure it is compatible with it.
 

LadyLion

Member
Jul 30, 2020
78
20
SF North Bay
This is the link to the soft start part from my old AC unit

Hyper Engineering SS1B16-32SN V230 Hyper Sure Start Single Phase Soft Starter 230V 16-32 FLA

The installers took photos of how it was connected and they plan to instal it on the new 5 ton Carrier AC.
It is the highest rated single phase soft start by Hyper Engineering. The comments mention Tesla installing it on some of the posters' solar/PW systems. It is highly rated.

Thank you for your help.
 
Apr 7, 2020
54
42
Houston
I have a 5 Ton Lennox 2 stage compressor and variable speed air handler. I don't need the soft start even when running much of the house on my gas powered portable generator (7.5 kw). The comp alwasy starts on stage 1 (low) and the air handler fan also starts out very slow and ramps. So the big electric motor surges are already significantly reduces.
 

holeydonut

Supporting Member
Supporting Member
Jun 27, 2020
2,361
1,705
East Bay NorCal
I have a 5 Ton Lennox 2 stage compressor and variable speed air handler. I don't need the soft start even when running much of the house on my gas powered portable generator (7.5 kw). The comp alwasy starts on stage 1 (low) and the air handler fan also starts out very slow and ramps. So the big electric motor surges are already significantly reduces.


Did your installer actually install your 2 stage Lennox correctly? My installer used the E30 iComfort thermostat but neglected to actually set up my 2 Stage unit with the Y1 and Y2 wires; and they didn't bother telling me. I had to raise a big stink about it, and they still haven't fixed it due to COVID.

Lennox Industries (out of Richardson, Texas) told me the single stage and dual stage is really just a gimmick... some installers are trained to install dual stage condensers as single stage. The dual stage is usually more trouble than it's worth, and just a way to get people to sign up for a sale.
 
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holeydonut

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Jun 27, 2020
2,361
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East Bay NorCal
@holeydonut
How did you discover that your Lennox was installed incorrectly?
It was my understanding that the compressor runs at 60% most of the time versus 100%.
How can you verify this?

You'll probably have to triangulate various methods to make sure you have more than two stages. Assuming you have a "normal" system (without a heat pump) with inside air-handler/furnace and outdoor condenser......


Go up to your iComfort thermostat touch-screen and...
1) Press the "9 box rubics cube looking icon" in the upper right
2) Go to Settings
3) Along the left-side of the screen enter "Advanced Settings" (with a red toolbox icon)
4) Choose "dealer control center"
5) Agree to the warning message that you're entering a dealer menu
6) Go to "installation report"
7) Go into "system" or "furnace" (it depends on your iComfort firmware)
8) Along the right hand side you'll see "outdoor unit". It'll either say single stage, dual stage, or variable stage.


If your system says "variable stage" just stop now. You're good to go.


BUT. even if your thermostat says "dual stage" you'll want to confirm things. So next, find your air handler or furnace. Near it will be a black plastic box with some blinking lights and an antenna. This is the "Lennox iComfort Hub". Open the black lid and take a gander at it. If you see:

A) If you see a sticker/label on the flap that says you have a S30 Communicating Thermostat. I'm 99.99% sure your outdoor system is set up for dual-stage if it said dual stage on the previous steps above.

B) If you see a sticker/label that says the following, please keep reading. Because if you see this sticker you have the E30 thermostat.
1




Ok so if you're here then you have the E30. And now you need to check if they wired your E30 for dual stage. Your hub will have 12 exposed screws in a nice horizontal row. Beneath each of these screws is a text label that says W1, W2, W3, G, Y2, Y1, etc etc etc. If you do not have a Y2 wire, then your system is set up for single stage only. If there is a Y2 wire, you have one last thing to check*.

If you're comfortable, turn off the breaker to your air conditioner. Go to your outdoor condenser and pop off the back panel. You should see the same color wire on the Y2 screw here as what you saw on the IComfort E30 hub's Y2 screw. I mean there's a chance your installer wired the Y2 wires then cut them... so I guess there's a 0.1% chance they are messing with you big time haha.

Anyway, if you saw "dual stage" on the thermostat installation report, confirmed you have a Y2 wire, and confirmed the Y2 is plugged into the condenser, then you should be confident you have dual stage. If any of this is not completed as I described, then it's likely your system is only running as single stage. If your condenser is only activated via Y1, but Y2 is not set up, then it's only running as single stage even if your thermostat thinks there are two stages.


In my case, my E30 was set up only for single stage only through the E30 hub dip switches. And I have no Y2 wire. So my installers jobbed me. Lennox corporate insisted to me that "homeowners can't tell the difference anyway" and "it's just a marketing gimmick" so who knows what's real.

Lennox iComfort systems (combination of the thermostat, air handler/furnace, and outdoor condenser) are smart communicating systems. They should get the S30 if installed as a set. The E30 thermostat is more of a crutch/haste-job to get a new Lennox component to work with other company stuff or older gear.

*Edit Note: I am skipping the step whereby you check the Y2 is connected to your furnace/air handler and then from there goes to your condenser. That step is kind of hard to check, and I don't want to explain how to reveal your air handler or furnace's panelboard and all that jazz.
 
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LadyLion

Member
Jul 30, 2020
78
20
SF North Bay
Re Load. I talked to Tesla tech, powerwalls.

The soft start model I have, link above, is Compressor Rated Load amps (RLA) 32 amps max and Voltage ratings (ac)220-240 volts.
The Carrier AC 5 ton is RLA up to 23 amps. The voltage is 208 to 230.
So the tech said it is compatible.
Thank you @Vines
 
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LadyLion

Member
Jul 30, 2020
78
20
SF North Bay
@holeydonut
You helped so much by alerting me to the single stage versus two stage condenser issues. Would you believe I went outside to talk to the tech about the two stage and the Y1 and Y2 wires and he told me the unit was a single stage! I said I purchased a two stage and he must be wrong. This morning he told me that a two stage unit was being delivered. They sent out the wrong AC unit!
I never would have known until the installation was complete and maybe I wouldn’t have even known then.
That was great information you posted. Many thanks. And serendipity that it was at the exact time I needed it!
 

holeydonut

Supporting Member
Supporting Member
Jun 27, 2020
2,361
1,705
East Bay NorCal
@holeydonut
You helped so much by alerting me to the single stage versus two stage condenser issues. Would you believe I went outside to talk to the tech about the two stage and the Y1 and Y2 wires and he told me the unit was a single stage! I said I purchased a two stage and he must be wrong. This morning he told me that a two stage unit was being delivered. They sent out the wrong AC unit!
I never would have known until the installation was complete and maybe I wouldn’t have even known then.
That was great information you posted. Many thanks. And serendipity that it was at the exact time I needed it!


Wow, glad I could help!

I've learned that this type of "mistake" of installing the wrong parts is more common than most would expect. It's almost par for the course for some installers because they realize the customers just don't know enough. Granted, some contractors are 100% above board, but there are other contractors and installers who "swap unit models all the time". The guys installing usually say they're just installing whatever was on the truck. But they've seen the work order; they're just instructed by their Ops teams to not say anything unless the customer notices.

The most common abuse of this is where the installers put in an undersized/cheap evaporator coil. The Air Conditioning Heating and Refrigeration Institute (AHRI) measures the "SEER" rating for how efficiently HVAC equipment can either reduce heat in a standard volume of air.

In almost all instances for central air conditioning (inside air handler + inside evaporator + outside condenser), a slightly larger evaporator coil from a good brand (not ADP) for your system size results in better SEER. For example, if you have a 3 ton AC, you should try to get a 3.5 or 4 ton evaporator coil*. But this costs a bit of extra money for the installer. So most will put in a 2.5 ton evaporator coil since it would still "match" the 3 ton setup and comply with AHRI rules. But the homeowner gets stuck with worse SEER, while the installer makes a few extra bucks.

And from what Lennox tells me, SEER is just a marketing gimmick as well. 16 SEER or 20 SEER... it's all the same (even though the testing methodology proves otherwise). I guess with long-career HVAC people, they know the regular homeowner isn't sophisticated so they can take advantage.

* Note: the slightly larger evaporator coil will be a bit worse for humidity management since the system will remove less moisture from the air. But if you're already in a relatively dry climate, going with an upsize evaporator coil is a smart move.
 
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LadyLion

Member
Jul 30, 2020
78
20
SF North Bay
@holeydonut
The replacement unit just arrived. The tech gave me the new booklet that comes with the unit. It is the same booklet they gave me yesterday. In other words they gave me the booklet for model 24ACB7 for a two stage compressor yesterday but they were installing a single stage unit. the coil is in the attic and I am unable to go up there. An ADP was what was specified in my contract, model #C60H210P176. I will confirm with the tech that it is correct.
 

holeydonut

Supporting Member
Supporting Member
Jun 27, 2020
2,361
1,705
East Bay NorCal
@holeydonut
The replacement unit just arrived. The tech gave me the new booklet that comes with the unit. It is the same booklet they gave me yesterday. In other words they gave me the booklet for model 24ACB7 for a two stage compressor yesterday but they were installing a single stage unit. the coil is in the attic and I am unable to go up there. An ADP was what was specified in my contract, model #C60H210P176. I will confirm with the tech that it is correct.


Looks like you got a 5 ton evaporator... so they didn't skimp there... unless they somehow mis-sized your condenser unit to be too small haha.

ADP isn't terrible... I just don't like them since they're the bargain brand owned by Lennox International. And Lennox kind of rubbed me the wrong way telling me all HVAC is just marketing gimmicks. Evidently you get the same thing buying a Bryant, York, and American Standard as you do when you go premium with Carrier or Lennox.

Did they replace your air handler and furnace as well? If you shoot me the full model numbers (like they're probably 15 characters long) of your new condenser and furnace we can check the SEER as measured by the AHRI.

If your furnace and evaporator are legacy (eg you only installed a new condenser) it's not possible to get a AHRI match. They only test certain popular combinations that are authorized to be sold as complete systems.
 
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LadyLion

Member
Jul 30, 2020
78
20
SF North Bay
@holeydonut

The furnace is Carrier Performance 96% efficient Two stage model # 59TP6A080V2120, 80,000 BTU with variable speed blower. (This number model number is taken from the contract. I haven’t seen the actual photo of the label yet.)

The AC is Carrier Performance 17 SEER rated efficient 2stage 5 ton model # 24ACB760A320 ( taken from the label of the replacement unit). They suggested the 5ton AC unit. It replaced a 4 ton and I questioned the change but I went with the 5ton, it wasn’t that much more $.

They are preparing to leave now. They did not attempt to instal the new Honeywell Vision Pro 8000 model TH8320R two stage heat and cooling thermostat and the Equipment Interface Module THM5421R1021 which I bought. Unfortunately the zone board I have is single stage and it appears after talking to Honeywell that I need a new zone board to accommodate the two stage thermostat system. They never brought this up and it makes me think they were just going to instal both heat and cooling as single stage. Yet they sold me a dual stage system! (Or the estimator didn’t know what he was doing. He knew which Honeywell thermostat I was buying.) They said they will figure this out and get back to me re coming back on Monday. They have left me with a working furnace single stage and inoperative AC since they didn’t finish the installation.
They did seal all ceiling registers with butyl tape in order to pass the required duct pressure test and HERS refrigeration test for permit approval.
My furnace and AC is not the high end Infinity communicating series by Carrier. I did not want a WiFi thermostat , just wireless.
( I can make it WiFi by buying a Redlink gateway. ) I also got two indoor wireless temperature sensors to work with the two thermostats, for the one zone upstairs and one zone downstairs. The thermostat does require two Y wires.
I want the wireless sensors to place near me versus near the thermostat mount on the wall which is a hot location near the ceiling register.
I think we are getting close to the solution. Thank you.
 
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holeydonut

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Supporting Member
Jun 27, 2020
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East Bay NorCal
Oh my bad... for some reason I thought you bought a new 3 ton Carrier condenser. That's why I was confused about the evaporator being 5 ton lol.

Anyway, the AHRI match on your air conditioning is 16 SEER. You didn't get the "advertised up to 17 SEER" because it's almost impossible for the larger tonnage systems to get the headline SEER. 16 SEER is pretty good, and your furnace is very efficient.

One of the reasons all these manufacturers invented their smart/wifi thermostats was to get the newer systems to work in older homes. Like my house only had single stage equipment. So the original thermostats only have 4 wires.

The new thermostats are now all "smart wifi," with their fancy hubs. And the hub has the Y2 and W2 wires for the dual stage cooling or heat (of course my installer didn't put those wires in, so whatever).

I guess since you have zoning and want remote temperature sensing... you're kind of stuck where the thermostats aren't smart enough for you, and your home doesn't have the required existing wiring. I hope Carrier has what you need; because Lennox wouldn't have a solution to work for the situation you described.
 
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LadyLion

Member
Jul 30, 2020
78
20
SF North Bay
Thanks for the verification of my SEER rating. I am in Marin and I don’t need air conditioning everyday in the summer, but it does reach high 90s in late summer. It will be interesting to see how the new system compares to the old one. Also if I can be totally self powered with Tesla solar and 3 PWs.
The EIM (Equipment Interface Module) is the Carrier solution to not having the extra wires. Each thermostat can wirelessly communicate with its own EIM that is connected to the furnace or the zone board. It is not WiFi internet but it’s own wireless system. Hopefully the installers will figure out how to make it work with a new zone board from Honeywell or a modification of the old one. If I had one zone it would have been easier.
Thanks again for the save!
 
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