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2xPowerwall whole house backup - HVAC sure start problem

SMAlset

Well-Known Member
Mar 4, 2017
9,068
9,786
SF Bay Area
BTW since I posted earlier in this thread about a sure-start that was going to be put on our old 2004 Carrier split 5 ton A/C unit with scroll wheel compressor, thought I should mention that it’s been working fine since install (Aug/Sept).
 

MXDogCrate

Member
Aug 27, 2018
118
36
California
Our installer (electricians) offered to install the "hard start" upgrades to our 3 air conditioners.

Instead, we contacted the company who services our HVAC systems (and did the original installation for our builder) and they did the upgrades - and now we can run all 3 air conditioners while operating off grid using our 4 PowerWalls. Though during an extended outage, we will likely only use 1 HVAC system to conserve power.
@bob_p Are you sure these are not soft start kits. We have an older model HVAC and the installer is telling us we need a soft start, not hard start kit. Very confused. TIA for the clarification.
 

Lloyd

Well-Known Member
Jan 12, 2011
6,284
2,085
San Luis Obispo, CA
Just to be sure: this problem is happening while you are connected to the grid? If so, the Powerwalls have nothing to do with it.

It sounds like the compressor is overheating, which could indicate an issue with the capacitors or the wiring for the start winding. The initial slow fan could indicate either a bad connection or they swapped the fan capacitor with one of the motor ones.

Likely not a controls compatibility issue as the fan keeps running.
A trick I heard of from the not so reputable repair guys is to damage or disconnect one of the start capacitors. When you call them to come back out, they sell you a new unit.
 

DoyleS

Member
Jul 10, 2020
64
18
El Dorado Hills, Ca
@bob_p Are you sure these are not soft start kits. We have an older model HVAC and the installer is telling us we need a soft start, not hard start kit. Very confused. TIA for the clarification.
Hard Start spikes the inrush current to the compressor. Soft start reduces inrush current typically 60% and is much better for HVAC units. Tesla is installing Soft Starts tomorrow during my Powerwalls installation on my 5 ton Scroll compressor and my 3 Ton which I assume is reciprocating.
 

wjgjr

Active Member
May 11, 2020
1,218
952
Silver Spring, MD
@bob_p Are you sure these are not soft start kits. We have an older model HVAC and the installer is telling us we need a soft start, not hard start kit. Very confused. TIA for the clarification.
To reduce the startup current (LRA) number, which is the key compatibility issue with an A/C and a limited number of PWs, you need a soft start kit. (And it does go by other names, like sure start.)
 

Doom Man

Member
Jan 22, 2020
37
33
New Orleans, LA
@bob_p Are you sure these are not soft start kits. We have an older model HVAC and the installer is telling us we need a soft start, not hard start kit. Very confused. TIA for the clarification.

My A/C tech did not know a "soft start" was a thing. He kept saying hard start and I kept telling him no, soft start. He called a few supervisors, who didn't know the difference either, so the tech eventually called the company owner, who knew the difference and set him on the right path. Once I convinced them that a soft start (SureStart brand) was the right device, the AC guys got it wired up right. It all works great.

The solar installer should know how to do this. I have a two-stage Daikin heat pump with (apparently) unusual wiring, so I had to have the HVAC company do it because the solar guys couldn't figure it out. Early adopter problems, I guess.
 
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holeydonut

Supporting Member
Jun 27, 2020
1,519
895
East Bay NorCal
My A/C tech did not know a "soft start" was a thing. He kept saying hard start and I kept telling him no, soft start. He called a few supervisors, who didn't know the difference either, so the tech eventually called the company owner, who knew the difference and set him on the right path. Once I convinced them that a soft start (SureStart brand) was the right device, the AC guys got it wired up right. It all works great.

The solar installer should know how to do this. I have a two-stage Daikin heat pump with (apparently) unusual wiring, so I had to have the HVAC company do it because the solar guys couldn't figure it out. Early adopter problems, I guess.


Your A/C tech sounds like the tech I had over at my house. They treat you like you're on drugs trying to explain a soft-start and they keep saying "you mean hard start?". Then you show them a soft start part online and they're like "quit wasting my time." Then they make two or three calls and angrily leave because even if they had the soft start in hand and a work order to install it... they wouldn't know how to install the part.

All in all terrible experience for everyone involved lol.
 
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DoyleS

Member
Jul 10, 2020
64
18
El Dorado Hills, Ca
My install is tomorrow for 2 Powerwalls. The lead Tesla installer called me today and went over everything. I had figured they would not back up my AC since the 5 ton with the Scroll Compressor still has an LRA of 140. He said that is not a problem, we will be putting soft starts on both of your AC units and everything will be backed up with the exception of a 100 amp Sub Panel Breaker for the upstairs sub panel. My service panel is a 400 amp panel and it has 2 master breakers. One is 200 amp and the other is 100 amp. This is not a problem for me as it is just upstairs plugs and lights. The 200 amp breaker has the pool, 2 ACs, Hot Tub, Ovens etc.
 

MXDogCrate

Member
Aug 27, 2018
118
36
California
My understanding is if you have a Scroll Compressor, you’re good to go on the Sure Start. My issue is my compressor doesn’t have a Scroll Compressor, but it’s possible a soft start kit from Trane will remedy. Not getting my hopes up.
 

MXDogCrate

Member
Aug 27, 2018
118
36
California
For anyone who wants to show the Sure Start Tesla currently uses to show to their HVAC contractor.
 

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daniel

Active Member
May 7, 2009
4,852
3,667
Kihei, HI
The HVAC people I called said I'd need to have an electrician do it. The electrician said I'd have to have an HVAC person do it. So I gave up. I'll have to make do with the ceiling fans during an outage. Too bad, because my solar powers the A/C easily except for the start. The cost of a new A/C isn't worth it. A/C here isn't a life-or-death essential.
 

DoyleS

Member
Jul 10, 2020
64
18
El Dorado Hills, Ca
My understanding is if you have a Scroll Compressor, you’re good to go on the Sure Start. My issue is my compressor doesn’t have a Scroll Compressor, but it’s possible a soft start kit from Trane will remedy. Not getting my hopes up.
We have 2 AC units. A 5 Ton with Scroll compressor an older 3 ton with a reciprocating compressor. Tesla is installing soft starts on both units. There are numerous Youtube videos on how to install.
 

BGbreeder

Member
Jun 19, 2020
237
132
Bay Area
The HVAC people I called said I'd need to have an electrician do it. The electrician said I'd have to have an HVAC person do it. So I gave up. I'll have to make do with the ceiling fans during an outage. Too bad, because my solar powers the A/C easily except for the start. The cost of a new A/C isn't worth it. A/C here isn't a life-or-death essential.
Hmmm... I'm sorry to hear that you are caught in a finger pointing catch 22.

Could you ask a different HVAC group? (I know that there often isn't a lot of alternative choices on the islands...) Wiring a Sure Start isn't exactly complicated in the grand scheme of things. (See the photos above).

All the best,

BG
 

MXDogCrate

Member
Aug 27, 2018
118
36
California
We have 2 AC units. A 5 Ton with Scroll compressor an older 3 ton with a reciprocating compressor. Tesla is installing soft starts on both units. There are numerous Youtube videos on how to install.
Thanks for this info. Now that I have the soft start manufacturer’s name, I will call and ask if this is possible. Thank you.
 

daniel

Active Member
May 7, 2009
4,852
3,667
Kihei, HI
Hmmm... I'm sorry to hear that you are caught in a finger pointing catch 22.

Could you ask a different HVAC group? (I know that there often isn't a lot of alternative choices on the islands...) Wiring a Sure Start isn't exactly complicated in the grand scheme of things. (See the photos above).

All the best,

BG

Daniel, If your HVAC and/or electrician is unable, it's time to find some better trades-people. This is not rocket science!

Not a lot of choices here. And upthread are some stories about these devices damaging compressors or just not working right. In addition, power outages lasting long enough to make a difference don't seem to happen often here. Lastly, when you try to find somebody to do any kind of work, if you are lucky enough to find somebody, it's liable to be months before they show up. I had a really hard time just finding a handyman for some repairs and renovations, and would probably still be looking if my realtor had not recommended a friend of hers, who agreed to do some work for me out of friendship with her.

I don't even know how to tell if I have a scroll or reciprocating compressor. And even with a SureStart, are two PWs even enough? I have no way to determine that.

Again, it only comes up a few times a year for very short periods and isn't life-threatening. I know people here who choose not to have or use A/C because they prefer the natural air. It would be nice to have A/C when there's an outage, but I guess it's not important enough to justify the aggravation of figuring stuff out and trying to find someone who can and will do the work.

I don't think a lot of people here have Powerwalls. Until recently solar installations here were all net-metered so it wasn't an issue and installers have no experience. I'll bet that if I found someone to work on mine, I'd be their first.

Too much verbiage just to say it's just not worth the bother here. Sorry.
 

Merrill

Merrill
Jan 23, 2013
3,855
1,347
Sonoma, California
Not a lot of choices here. And upthread are some stories about these devices damaging compressors or just not working right. In addition, power outages lasting long enough to make a difference don't seem to happen often here. Lastly, when you try to find somebody to do any kind of work, if you are lucky enough to find somebody, it's liable to be months before they show up. I had a really hard time just finding a handyman for some repairs and renovations, and would probably still be looking if my realtor had not recommended a friend of hers, who agreed to do some work for me out of friendship with her.

I don't even know how to tell if I have a scroll or reciprocating compressor. And even with a SureStart, are two PWs even enough? I have no way to determine that.

Again, it only comes up a few times a year for very short periods and isn't life-threatening. I know people here who choose not to have or use A/C because they prefer the natural air. It would be nice to have A/C when there's an outage, but I guess it's not important enough to justify the aggravation of figuring stuff out and trying to find someone who can and will do the work.

I don't think a lot of people here have Powerwalls. Until recently solar installations here were all net-metered so it wasn't an issue and installers have no experience. I'll bet that if I found someone to work on mine, I'd be their first.

Too much verbiage just to say it's just not worth the bother here. Sorry.
From my perspective you are living in paradise if things get bad you can sit on your porch and have a Mai Tai, I love Hawaii my wife and I were married on Maui back in the early 70’s.
 

holeydonut

Supporting Member
Jun 27, 2020
1,519
895
East Bay NorCal
From my perspective you are living in paradise if things get bad you can sit on your porch and have a Mai Tai, I love Hawaii my wife and I were married on Maui back in the early 70’s.


I think it's funny the native Hawaiians I've met tell me Paradise got old real fast and they wanted to get out of there.
 

BGbreeder

Member
Jun 19, 2020
237
132
Bay Area
Daniel, I hear you, and I think you are being very reasonable.

I used to be over on Oahu, and tradespeople seemed to always be in short supply, even there. The demand was there, but it just seemed not to be an attractive vocation. I ended up teaching myself how to do almost everything, though installing HVACs was where I drew the line.

I miss the kamaʻāinas, the ease of daily living, and the fresh fruit, but not the constant maintenance, nor the cost of living.

All the best,

BG
 

daniel

Active Member
May 7, 2009
4,852
3,667
Kihei, HI
From my perspective you are living in paradise if things get bad you can sit on your porch and have a Mai Tai, I love Hawaii my wife and I were married on Maui back in the early 70’s.

No alcohol for me. Recovered alcoholic. Don't crave it anymore, don't even like it any more. Actually, I don't think I ever liked it. I drank because I was depressed and alcohol just made me more depressed. Cardio pretty much cured my depression. And living on Maui it's not an issue.

I think it's funny the native Hawaiians I've met tell me Paradise got old real fast and they wanted to get out of there.

That's because you met the ones who left. :)

Daniel, I hear you, and I think you are being very reasonable.

I used to be over on Oahu, and tradespeople seemed to always be in short supply, even there. The demand was there, but it just seemed not to be an attractive vocation. I ended up teaching myself how to do almost everything, though installing HVACs was where I drew the line.

I miss the kamaʻāinas, the ease of daily living, and the fresh fruit, but not the constant maintenance, nor the cost of living.

All the best,

BG

It is expensive. It's bound to be when everything but pineapples and mangoes has to be shipped or flown in from 2,500 miles way.
 
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