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2xPowerwall whole house backup - HVAC sure start problem

SMAlset

Well-Known Member
Mar 4, 2017
9,053
9,777
SF Bay Area
Another thing to consider for adding soft starts is that they could void your warranty.

I have Dual Stage Lennox XC21s and had a Licensed/Trained/Certified/whatever Lennox technician on site to install soft-starts. But he called HQ and Lennox told him that they would not allow soft starts to be installed on my equipment otherwise I would void the warranty on the condensers. They added that:

1) Lennox Industries had no documented instance of anyone ever installing a Soft Start on their current generation of residential compressors (includes all of their current Merit, Elite, and Signature lines).

2) Soft starts are not recommended on Lennox's older, dual stage equipment since the soft start cannot properly learn the in-rush current demands of both the single and dual stages


Wow that's crappy to find out. We have an old 2004 Carrier 5-ton split unit, and the manual for it has what they call Compressor Start Assist under Accessories for it. From what I understand our model will work with the SureStart but nice to know the manufacturer has its own part as well.

We will eventually be replacing our unit and will keep in mind that we don't want a two-stage a/c for this very reason. Anyone know if the reason the 2-stage won't work with one would also apply to a variable speed a/c unit?
 
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MIT_S60

Active Member
Nov 23, 2016
1,047
892
Orange County, CA
Another thing to consider for adding soft starts is that they could void your warranty.

I have Dual Stage Lennox XC21s and had a Licensed/Trained/Certified/whatever Lennox technician on site to install soft-starts. But he called HQ and Lennox told him that they would not allow soft starts to be installed on my equipment otherwise I would void the warranty on the condensers. They added that:

1) Lennox Industries had no documented instance of anyone ever installing a Soft Start on their current generation of residential compressors (includes all of their current Merit, Elite, and Signature lines).

2) Soft starts are not recommended on Lennox's older, dual stage equipment since the soft start cannot properly learn the in-rush current demands of both the single and dual stages
I would find out if your unit has a Copeland scroll compressor inside, and which model it has. Then I'd check if that model shows as compatible for the Secure Start on the following website:
SecureStart™ for Copeland Compressors | Emerson US

If it's shows as compatible, I'd push back on Lennox.
 

holeydonut

Supporting Member
Jun 27, 2020
1,487
873
East Bay NorCal
I would find out if your unit has a Copeland scroll compressor inside, and which model it has. Then I'd check if that model shows as compatible for the Secure Start on the following website:
SecureStart™ for Copeland Compressors | Emerson US

If it's shows as compatible, I'd push back on Lennox.


Interesting... the dual-stage Lennox XC21 Copeland compressor part number is zps40k5e-pfv-130 (ZPSK5). The LRA on this is like over 110A.

Emerson's own product page seems to indicate the SecureStart wouldn't work with it...
Copeland Scroll&#8482 Two-Stage 1-5 HP ZPSK5 | Emerson

The only "start capacitor" Emerson says to use on this compressor is:
https://s3.amazonaws.com/s3.supplyh.../Copeland-ZP42K5E-PFV-830-Submittal-Sheet.pdf (014-0061-27)

Anyway, no soft starts = no Powerwall backing up the ACs :(
 

RKCRLR

Member
Apr 13, 2020
392
142
Garden Valley, CA
There is a difference between "hard" start kits (capacitors) and soft start kits. Most manufacturer's start kits are hard start kits. Hard start kits are for older compressors which have problems starting and give them a little "boost". This is the opposite of what you are looking for with a soft start kit where you are trying to minimize the inrush current.
 
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BIC1

Member
Feb 19, 2020
81
16
Missouri USA
Another thing to consider for adding soft starts is that they could void your warranty.

I have Dual Stage Lennox XC21s and had a Licensed/Trained/Certified/whatever Lennox technician on site to install soft-starts. But he called HQ and Lennox told him that they would not allow soft starts to be installed on my equipment otherwise I would void the warranty on the condensers. They added that:

1) Lennox Industries had no documented instance of anyone ever installing a Soft Start on their current generation of residential compressors (includes all of their current Merit, Elite, and Signature lines).

2) Soft starts are not recommended on Lennox's older, dual stage equipment since the soft start cannot properly learn the in-rush current demands of both the single and dual stages
I have new Carrier equipment and asked my HVAC contractor about the warranty. He said no problem, just won't warranty any issues directly related to the soft-start (which would be a soft-start warranty issue). That makes sense. Soft-starts actually help extend the life of the AC units.
 

holeydonut

Supporting Member
Jun 27, 2020
1,487
873
East Bay NorCal
I have new Carrier equipment and asked my HVAC contractor about the warranty. He said no problem, just won't warranty any issues directly related to the soft-start (which would be a soft-start warranty issue). That makes sense. Soft-starts actually help extend the life of the AC units.


That's great that Carrier actually allows soft starts (or sure starts)!

But be careful that the soft start directly interfaces with the compressor. I hope they do not assign proximate cause of a soft start failure interacting with the compressor... this could impact the assessment of their warranty on the compressor. The cost of the compressor in a Lennox is like half that of the entire condenser unit haha.

BTW, I really regret going with Lennox for my HVAC overhaul. Ugh.
 

DavidinSF

New Member
Jun 6, 2014
3
0
San Francisco and Napa
I have 2 AC units and appear to have Sure Starts listed in my equipment list details:

EE-009508-016 Soft Starter, 230V, 60/50Hz, 08-16 RLA Sure-Start # SS1B08-16SN
EE-009516-032 Soft Starter, 230V, 60/50Hz, 16-32 RLA Sure-Start # SS1B16-32SN

I had 2 Tesla Powerwalls installed last fall for whole-house back up. happy with it, no issues there.

A few days ago, my AC unit stopped working...probably capacitor or connector, still waiting for tech. But when I opened the unit, I saw a SureStart device installed but not plugged to anything. All the cables and extra fuses are sitting there in a baggie. Did they miss something or is this the norm, to install and leave it there just in case?
 

DavidinSF

New Member
Jun 6, 2014
3
0
San Francisco and Napa
I had 2 Tesla Powerwalls installed last fall for whole-house back up. happy with it, no issues there.

A few days ago, my AC unit stopped working...probably capacitor or connector, still waiting for tech. But when I opened the unit, I saw a SureStart device installed but not plugged to anything. All the cables and extra fuses are sitting there in a baggie. Did they miss sometyhing or is this the norm, to install and leave it there just in case?
 

RKCRLR

Member
Apr 13, 2020
392
142
Garden Valley, CA
I had 2 Tesla Powerwalls installed last fall for whole-house back up. happy with it, no issues there.

A few days ago, my AC unit stopped working...probably capacitor or connector, still waiting for tech. But when I opened the unit, I saw a SureStart device installed but not plugged to anything. All the cables and extra fuses are sitting there in a baggie. Did they miss sometyhing or is this the norm, to install and leave it there just in case?
Does your AC work during power outages?
It's possible your AC doesn't need the SureStart but it is a little strange that it is installed but not connected. Mine isn't connected but it is because my AC doesn't work correctly with it connected and they haven't come up with a final resolution.
 

holeydonut

Supporting Member
Jun 27, 2020
1,487
873
East Bay NorCal
I LOL'd when I read that they put the SureStart device into the condenser casing but left the wires in the baggie. That's definitely not how it's supposed to be wired up.

When the SureStart is connected properly, it'll affect the amount of current draw any time the AC compressor turns on (doesn't matter if your PG&E energy is available or not).

The SureStart is NOT a device that you have to set up when the PG&E power goes out.

Did you happen to get a Lennox? Sounds like something their tech's would do
 

RKCRLR

Member
Apr 13, 2020
392
142
Garden Valley, CA
I LOL'd when I read that they put the SureStart device into the condenser casing but left the wires in the baggie. That's definitely not how it's supposed to be wired up.

When the SureStart is connected properly, it'll affect the amount of current draw any time the AC compressor turns on (doesn't matter if your PG&E energy is available or not).

The SureStart is NOT a device that you have to set up when the PG&E power goes out.

Did you happen to get a Lennox? Sounds like something their tech's would do
Not sure if we're on the same page here or not.
Depending on the AC design, the Powerwalls may not be able to provide enough current to start the compressor when the grid is down. The SureStart is intended to reduce the current required to start the compressor.
In my case, the Powerwalls can only start the compressor if the timing is right and the solar is producing (the Gateway hasn't commanded the solar to stop producing) when the AC tries to start with the grid down.
My compressor isn't compatible with SureStart (installed by Tesla) and won't work at all (grid down or not) when the SureStart is connected.
 
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holeydonut

Supporting Member
Jun 27, 2020
1,487
873
East Bay NorCal
Not sure if we're on the same page here or not.
Depending on the AC design, the Powerwalls may not be able to provide enough current to start the compressor when the grid is down. The SureStart is intended to reduce the current required to start the compressor.
In my case, the Powerwalls can only start the compressor if the timing is right and the solar is producing (the Gateway hasn't commanded the solar to stop producing) when the AC tries to start with the grid down.
My compressor isn't compatible with SureStart (installed by Tesla) and won't work at all (grid down or not) when the SureStart is connected.


Yes, the Sure Start (when it's actually plugged in) will reduce the "Locked Rotor Amps" (LRA) requirement to get your compressor to start. But, my point is the Sure Start does this benefit if it's using your PG&E grid power or with your PowerWall power.

So when the Tech came out to install the Sure Start, he/she was supposed to wire it in place so it's not just sitting in your compressor with a baggie of wires. They were supposed to integrate it into your compressor.

The point of the Sure Start is that it's wired to the compressor so that regardless of energy source, the compressor now has a lower LRA and lower "in-rush current" upon startup. An air conditioner condenser unit with Sure Starts can be safely backed up by the Powerwall when the Utility has failed.

More info about the Sure Start is in their brochure:
https://climate.emerson.com/documents/securestart-brochure-en-us-4475386.pdf

One important thing about the Sure Start is that it has to "learn" the specific pattern of inrush current for the ~50 milliseconds of peak LRA that a compressor draws upon startup. So you need to test the Sure Start with the utility working a few times before you can rely on it to provide the lower LRA benefit when you're on battery power.
https://climate.emerson.com/documen...rt-for-copeland-compressors-en-us-4475396.pdf
 

Freakyguy666

Member
May 14, 2020
60
13
USA
Yes, the Sure Start (when it's actually plugged in) will reduce the "Locked Rotor Amps" (LRA) requirement to get your compressor to start. But, my point is the Sure Start does this benefit if it's using your PG&E grid power or with your PowerWall power.

So when the Tech came out to install the Sure Start, he/she was supposed to wire it in place so it's not just sitting in your compressor with a baggie of wires. They were supposed to integrate it into your compressor.

The point of the Sure Start is that it's wired to the compressor so that regardless of energy source, the compressor now has a lower LRA and lower "in-rush current" upon startup. An air conditioner condenser unit with Sure Starts can be safely backed up by the Powerwall when the Utility has failed.

More info about the Sure Start is in their brochure:
https://climate.emerson.com/documents/securestart-brochure-en-us-4475386.pdf

One important thing about the Sure Start is that it has to "learn" the specific pattern of inrush current for the ~50 milliseconds of peak LRA that a compressor draws upon startup. So you need to test the Sure Start with the utility working a few times before you can rely on it to provide the lower LRA benefit when you're on battery power.
https://climate.emerson.com/documen...rt-for-copeland-compressors-en-us-4475396.pdf
The brochure says SECURE START. Is that the same as Sure Start?
 

holeydonut

Supporting Member
Jun 27, 2020
1,487
873
East Bay NorCal

persol

New Member
Sep 13, 2020
1
1
Pennsylvania
I wish I'd found this thread before I called my HVAC guy out. The Tesla installer said my heat pump is on a non-backed-up circuit (it's on the top breaker in the 'tesla backup gateway 2' box).

Noticed yesterday my outside unit fan was humming without moving, I tested the capacitor, and it was bad. Verified I was getting 230V, so figured it was unrelated to the solar install a few days ago. I replaced the cap, fan now spins (seems to spin slow), but the compressor doesn't turn on. I call out my original HVAC installed and the guy says "we didn't install this and I don't know what it does":
EE-009508-016 Soft Starter, 230V, 60/50Hz, 08-16 RLA Sure-Start # SS1B08-16SN

Sure enough, 230V is going into the soft starter, but not coming out. It's dated '2020', so it had to be the Tesla installers.

Reading this thread, I have no idea why it was even installed since it's not on a backed up circuit anyhow.
 
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MXDogCrate

Member
Aug 27, 2018
118
36
California
We’re in the middle of an install. PW Guys arrived today. Our HVAC unit is over 20 years old, but still humming fingers crossed.

They just informed us because the unit doesn’t have a scroll compressor it cannot be backed up by two PWs.

Pretty sad about this.
 

nwdiver

Well-Known Member
Feb 17, 2013
7,939
10,301
United States
We’re in the middle of an install. PW Guys arrived today. Our HVAC unit is over 20 years old, but still humming fingers crossed.

They just informed us because the unit doesn’t have a scroll compressor it cannot be backed up by two PWs.

Pretty sad about this.

I looked into helping a former co-worker go all electric on his home. We were able to find a HVAC tech willing to replace his HVAC for ~$1500 with the unit of his choice. The 'Mr Cool Universal' is < $4k. So if you can find an HVAC installer that won't rip you off you could upgrade to a ~17 SEER that your PWs could easily run for maybe <$6k.

Especially since your current HVAC is 20 years old and and probably a SEER ~10, depending on how much you use your AC that ~$6k could reduce your energy use by more kWh annually than ~$6k invested in solar could produce.
 
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MXDogCrate

Member
Aug 27, 2018
118
36
California
Thanks, @nwdiver!

In speaking with the PW lead - the one who would have installed the SureStart. He said he personally just installed a new HVAC unit on his house with variable RA. In his opinion, more energy efficient, but none of them are very energy efficient.

Thanks for the recommendation. Will def look into it.
 

fun33

New Member
Oct 27, 2020
1
0
Kissimmee Florida
My 2 Powerwalls were installed 2 1/2 years ago with a SureStart. In the past month, I have been hearing a 10-15 second high pitched tone coming from my outdoor HVAC coil where the Surestart is installed.

Has anyone else experienced this high pitched tone? Is it an indication the Surestart is about to fail?
 

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