Decoding Equipment Specs: Please help me understand this Equipment Spec??????

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dionysius

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Would the MOP spec of 25A on each of the 3 phases be the OCPD breaker trip to use???
I am not sure I fully understand where the linearity/pf is specified.

The full spec is at the link but to make it easy I have abstracted below the electrical power specs of interest and put in my questions in underscored italics.......

Rated Cooling Capacity (Btu/hr): 110,000 Rated Heating Capacity (Btu/hr): 126,000
Nom Cooling Capacity (Btu/hr): 120,000 Nom Heating Capacity (Btu/hr): 135,000
Cooling Input Power (kW): 8.21 Heating Input Power (kW): 12.40


OUTDOOR UNIT DETAILS
Power Supply (V/Hz/Ph): 460 / 60 / 3 Compressor Type Inverter.....so it is nominal 480v 3 phase 60Hz???
Power Supply Connections: L1, L2, L3 Ground
Capacity Control Range (%): 10 - 100......... what does this mean???
Min. Circuit Amps MCA (A): 21.10......... what does this really mean???
Max Overcurrent Protection (MOP) (A): 25.00 ......... does this mean use 25A breaker for OCPD on each phase???
Rated Load Amps RLA(A): 6.8+6.8 .........This is cryptic..does this mean that under normal operation it uses 2x6.8A = 13.6A???



Full spec sheet is here:
http://www.daikinac.com/content/assets/DOC/SubmittalDataSheets/VRV/REYQ/460v/SDS-REYQ120TYDN.pdf
 
OUTDOOR UNIT DETAILS
Power Supply (V/Hz/Ph): 460 / 60 / 3 Compressor Type Inverter.....so it is nominal 480v 3 phase 60Hz??? Yes
Power Supply Connections: L1, L2, L3 Ground
Capacity Control Range (%): 10 - 100......... what does this mean??? I have no clue. But I dont think you need to worry about it if you are just running the circuit.
Min. Circuit Amps MCA (A): 21.10......... what does this really mean??? This is the minimum rating the circuit should be. All wiring should be capable of handling21.1 Amps
Max Overcurrent Protection (MOP) (A): 25.00 ......... does this mean use 25A breaker for OCPD on each phase??? This means the largest breaker you can install would be a 25 amp, 3 pole breaker, rated for 277/480V.
Rated Load Amps RLA(A): 6.8+6.8 .........This is cryptic..does this mean that under normal operation it uses 2x6.8A = 13.6A???d Thats a head scratcher.
 
If you're just looking to provide a circuit for the unit the only real info that you need is the MCA and the MaxOCPD. As SE stated use the MCA to determine the minimum conductor size the the MaxOCPD to size the overcurrent protection device.
 
FYI, the
Capacity Control Range (%): 10 - 100
entry just means that the inverter (VFD) operated compressor can be throttled down all the way from 100% of the 10 ton rated capacity to deliver as little as 10% (1 ton capacity) without having to cycle the compressor on and off.
 
GoldDigger said:
FYI, the
Capacity Control Range (%): 10 - 100
entry just means that the inverter (VFD) operated compressor can be throttled down all the way from 100% of the 10 ton rated capacity to deliver as little as 10% (1 ton capacity) without having to cycle the compressor on and off.
Click to expand...

That does make sense and is there for a control system designer I presume.
 
Smart $ said:
Units has two compressors
Click to expand...
More likely a 6.8A compressor and a 6.8A fan, or one compressor and two fans that are 3.4A each, something like that, but you may never know without an internal schematic or if you take one apart. I would think the coolant control system would be complicated with two compressors.

The fact is, this is why they don't typically provide the details, it can be too confusing. So they boil it down to what YOU as the installer need to know, which is what infinity said at the outset; how to size the conductors and what breaker or fuse to feed it from.
 
Excellent responses, thank you all.

To install 5 (yes 5 side by side) of these outside units about 50 ft from the 480/277 panel would you use for each one:
​


4 #10AWG Cu (A,B,C,N) in 3/4" EMT w conduit as ground and 25A common trip breaker​

Anyone got a better solution to save on labor and/or material?????
 
dionysius said:
Excellent responses, thank you all.

To install 5 (yes 5 side by side) of these outside units about 50 ft from the 480/277 panel would you use for each one:

4 #10AWG Cu (A,B,C,N) in 3/4" EMT w conduit as ground and 25A common trip breaker​

Anyone got a better solution to save on labor and/or material?????
Click to expand...
Why would you include a neutral?

Roger
 
dionysius said:
To install 5 (yes 5 side by side) of these outside units about 50 ft from the 480/277 panel would you use for each one:

4 #10AWG Cu (A,B,C,N) in 3/4" EMT w conduit as ground and 25A common trip breaker​

Anyone got a better solution to save on labor and/or material?????
Click to expand...

Run 2-3/4" EMT's, pull 3 sets of #10's in one and two sets in the other. The EMT with two sets you could use #12's. Use 3 pole 25 amp circuit breakers.
 
infinity said:
Run 2-3/4" EMT's, pull 3 sets of #10's in one and two sets in the other. The EMT with two sets you could use #12's. Use 3 pole 25 amp circuit breakers.
Click to expand...
3 sets of #12 derate to 21A (with no other derating), should sufficient for a 21.10 MCA. 220.5 permits us to round fractional ampere values to the nearest whole number. However, there may be some question whether that stipulation carries to other articles, or more specifically where no calculation is performed, such as in this case the MCA being a rating, not a calculation. Opinions?
 
Smart $ said:
3 sets of #12 derate to 21A (with no other derating), should sufficient for a 21.10 MCA. 220.5 permits us to round fractional ampere values to the nearest whole number. However, there may be some question whether that stipulation carries to other articles, or more specifically where no calculation is performed, such as in this case the MCA being a rating, not a calculation. Opinions?
Click to expand...

I would say it is a calculation performed by the manufacturer not a rating.

How would a MCA be a rating?
 
dionysius said:
Excellent responses, thank you all.

To install 5 (yes 5 side by side) of these outside units about 50 ft from the 480/277 panel would you use for each one:

4 #10AWG Cu (A,B,C,N) in 3/4" EMT w conduit as ground and 25A common trip breaker​

Anyone got a better solution to save on labor and/or material?????
Click to expand...


Is there an outlet nearby? Dont forget about 210.63.
 
Smart $ said:
3 sets of #12 derate to 21A (with no other derating), should sufficient for a 21.10 MCA. 220.5 permits us to round fractional ampere values to the nearest whole number. However, there may be some question whether that stipulation carries to other articles, or more specifically where no calculation is performed, such as in this case the MCA being a rating, not a calculation. Opinions?
Click to expand...

21.1 is the minimum size, 21.0 is less = no good. That why I said to use #10's with the 9 CCC's. :D In the real world it will make absolutely no difference but...
 
Smart $ said:
Actually not. I looked in the service manual.

http://www.daikinac.com/content/assets/DOC/ServiceManuals/SM-VRV-IV-HR.pdf
Click to expand...
Interesting. I had not looked at a manual or anything. The coolant circuit is interesting though, there is some sort of little capillary tube running between the compressors, that must be how they solved what I was thinking was going to be complex. My exposure to refrigeration theory was all of 2 classes in college and a little OJT over the last 30+ years, it's not really my thing, but I was thinking that was an issue.

That's why I'm not an ME I guess...
 
infinity said:
21.1 is the minimum size, 21.0 is less = no good. That why I said to use #10's with the 9 CCC's. :D In the real world it will make absolutely no difference but...
Click to expand...
"But..." leads to details.

21.0 is less than 21.1... but using the rules of significant figures, the result of 30A × 70% is 21... not 21.0.

In comparing with the MCA value, we can only use two significant figures. 21.1 becomes 21... thus 21A = 21A and is good to go.

:angel: :D
 
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