Mini Split Voltage

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Dennis Alwon

Dennis Alwon

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If a mini-split units is marked 208/230 with a max 253V and min 187 is this allowed on a 240v circuit. I know it would be fine as it would be in the voltage range but with 208/230 it is confusing.
 
hbiss said:
Are you concerned that the nominal 240 could exceed 253 max? My opinion is that if they sell the equipment in this country they have that covered. I wouldn't worry about it.

-Hal
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No, My concern is the nameplate 208/230 is exceeded with 240v
 
We either have ignorant manufacturers (I Hope), or sneaky manufacturers (I Hope NOT). We generally refer to the 120*root(3) (about 207.85) as 208. There have been numerous postings of NEMA standards here, but if we are referring to voltages of utilization, 115/200/230/460/575, they correlate. If we prefer to use the nominal supply, it would be 120/208/240/460/600, they correlate.

Thus we have an ignorant label creator who uses wye connected voltage associated with 208y120 but the equipment utilization 240 usually associated with residential 120-0-120 line-to-line. They should, IMHO, have used either 200/230 or 208/240. Whatever, it would be very unlikely that the 253 max would be exceeded in practice.
 
curt swartz said:
I don't think I have ever seen HVAC equipment marked 240. Is always marked 230 or 208/230
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Same with motors.
In that case, they are basically a 230V design that will give (somewhat) acceptable life when operated on a 208V system. It can be considered somewhat dubious.

ETA: In Dennis’ case, I think his equipment will operate fine on 240V.
 
Dennis Alwon said:
No, My concern is the nameplate 208/230 is exceeded with 240v
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The utilization voltage of 230 is the correct voltage for a nominal 240 volt system.

This is a problem with the language in 110.4, but the CMP refuses to make a change.

The utilization voltages of 115, 200, 230 and 460 are for use on system voltages of 120. 208, 240 and 480 respectively.
 
Thanks all. I knew it was safe but I guess I never noticed it was labelled 230v. I remember we had a motor for an elevator namplate at 230v. We wired it 240v and they blew a fit about it. They had to get us a trany that would work....... I had a thread on that a while ago.
 
Dennis Alwon said:
I remember we had a motor for an elevator namplate at 230v. We wired it 240v and they blew a fit about it. They had to get us a trany that would work....... I had a thread on that a while ago.
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That's a shame. The motor would probably run better and cooler on the 240v.
 
hbiss said:
And what was the general consensus about it there? This is no different.

-Hal
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The general consensus was it was bull but the manufacturer specifically told me I needed a trany before we started the job. I had forgotten and they didn't bring one like they were supposed to. They insist it had to be 230v. Why did they make a motor with those parameters I will never know.

I now the motor I mention was not a functioning issue. I was wondering why when it is marked 230v we can legally use 240 based on nameplate info. I think Don gave the reasoning.
 
Dennis Alwon said:
The general consensus was it was bull but the manufacturer specifically told me I needed a trany before we started the job. I had forgotten and they didn't bring one like they were supposed to. They insist it had to be 230v. Why did they make a motor with those parameters I will never know.

I now the motor I mention was not a functioning issue. I was wondering why when it is marked 230v we can legally use 240 based on nameplate info. I think Don gave the reasoning.
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Here is a very good resource:

I also like this chart:
 

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I get all that. I was comparing it to say a water heater that's marked 208v and you install it at 240V or vice versa. That will work all day but it is not compliant per the manufacturers info (it's listing)
 
Dennis Alwon said:
I get all that. I was comparing it to say a water heater that's marked 208v and you install it at 240V or vice versa. That will work all day but it is not compliant per the manufacturers info (it's listing)
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Well, one will certainly work longer than the other.
 
Dennis Alwon said:
If a mini-split units is marked 208/230 with a max 253V and min 187 is this allowed on a 240v circuit.
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Look at it this way. The only thing you have in writing is the label that says "208/230 with a max 253V and min 187". Do you have a label on your panel or anywhere else that says "120/240"? Or is it only us being anal and saying that it's called 120/240, not 120/230?

Guess what, if we don't tell anybody nobody will know and your A/C will work just fine. ;)

-Hal
 
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