NEW SEER(2) EFFICIENCY RATINGS - For 2023

[mtnelect]

Heads up to the Electricians out there, the Department of Energy has increased the SEER ratings, depending on your area it is now 14.5 or 15. Consequently, the MOP & MCA have changed. So, when you wire up a new unit using the existing circuit pay attention to the label on the unit.

 

[mtnelect]

Also, the refrigerant has changed from R410A to R454B, which is now slightly more flammable.

 

[gadfly56]

Also, the refrigerant has changed from R410A to R-454B, which is now slightly more flammable.

Of course, why not??

 

[infinity]

Consequently, the MOP & MCA have changed. So, when you wire up a new unit using the existing circuit pay attention to the label on the unit.

Wouldn't you need to check the new ratings even if the minimum SEER ratings regulation didn't change? I guess that you're saying when you change out an existing unit the OCPD might need to be changed. The MCA probably wouldn't matter.

 

[mtnelect]

Wouldn't you need to check the new ratings even if the minimum SEER ratings regulation didn't change? I guess that you're saying when you change out an existing unit the OCPD might need to be changed. The MCA probably wouldn't matter.

Correct, some new units, the MCA, and MOP goes down if they are under 45K and go up if they are above. But if the MOP is used when wired no change is needed.

 

[infinity]

Correct, some new units, the MCA, and MOP goes down if they are under 45K and go up if they are above.

Interesting. You're saying that in a ton for ton swap some new units with a higher SEER than the old unit will have a higher MaxOCPD and MCA?

 

[mtnelect]

Interesting. You're saying that in a ton for ton swap some new units with a higher SEER than the old unit will have a higher MaxOCPD and MCA?

This is from the Carrier Inservice Training:

"When new compressors are tested by compressor manufacturers, sometimes the MCC (Maximum Continuous Current) rating is higher than previous generation with equal capacity".

"The maximum amperage a compressor will draw during agency testing before tripping on its overload".

"The MCC value is measured at a non-standard condition and equipment manufacturers are still required to compare a percentage of its value to the end unit agency test value. The higher value must be used to while the equipment has some flexibility to adjust the Maximum Overcurrent Protection, final MOP must meet UL and NEC requirements".

 

[nizak]

Many times no attention at all is paid to the breaker size that is usually in a remote place without access.

Reconnecting made at the unfused unit disconnect . 50 amp breaker from 40 years ago has fed the last 2 units regardless of their efficiency.

 

[augie47]

We experienced a similar problem when the "high efficiency" air handlers became available.
Air Handlers with 10kw heat strips is the norm here and for eons HVAC folks installed wiring based on a MCA of 55 amps or less which is not the case on some of the newer units. A lot of #6NM was replaced or heat strips downsized.