Contractor:
P.O.:
Engineer:
Project Name:
Unit Tag:
The manufacturer works continually to improve its products. As a result, the design and speci
fi
cations of each product at the time of order may be changed without notice. Purchaser’s approval of this data set signi
fi
es that the equipment is acceptable under the provisions
of the job speci
fi
cation. Statements and other information contained herein are not express warranties and do not form the basis of any bargain between the parties, but are merely the manufacturer’s opinion or commendation of its products. York and Af
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nity are registered
trademarks of Johnson Controls, Inc., and are used with permission.
Operating Limits
De
fi
nitions
Abbreviations and Definitions
cfm
= airflow, cubic feet/minute
EWT = entering water temperature, Fahrenheit
gpm = water flow in gallons/minute
WPD = water pressure drop, psi and feet of water
EAT = entering air temperature, Fahrenheit (dry bulb/wet bulb)
HC
= air heating capacity, MBtu/h
TC
= total cooling capacity, MBtu/h
SC
= sensible cooling capacity, MBtu/h
kW
= total power unit input, kilowatts
HR
= total heat of rejection, MBtu/h
HE
= total heat of extraction, MBtu/h
HWC = hot water generator capacity, MBtu/h
EER = Energy Efficient Ratio
= Btu output/Watt input
COP = Coefficient of Performance
= Btu output/Btu input
LWT = leaving water temperature, °F
LAT
= leaving air temperature, °F
TH
= total heating capacity, MBtu/h
LC
= latent cooling capacity, MBtu/h
S/T
= sensible to total cooling ratio
Operating Limits
Cooling
Heating
(°F)
(°C)
(°F)
(°C)
Air Limits
Min. Ambient Air
45
7.2
45
7.2
Rated Ambient Air
80
26.7
70
21.1
Max. Ambient Air
100
37.8
85
29.4
Min. Entering Air
50
10.0
40
4.4
Rated Entering Air db/wb
80.6/66.2
27/19
68
20.0
Max. Entering Air db/wb
110/83
43/28.3
80
26.7
Water Limits
Min. Entering Water
30
-1.1
20
-6.7
Normal Entering Water
50-110
10-43.3
30-70
-1.1
Max. Entering Water
120
48.9
90
32.2
NOTE:
Minimum/maximum limits are only for start-up conditions, and are meant
for bringing the space up to occupancy temperature. Units are not designed to
operate at the minimum/maximum conditions on a regular basis. The operating
limits are dependent upon three primary factors: 1) water temperature, 2) return
air temperature, and 3) ambient temperature. When any of the factors are at the
minimum or maximum levels, the other two factors must be at the normal level for
proper and reliable unit operation.
HE
gpm x 500
Reference Calculations
Heating Calculations:
Cooling Calculations:
LWT = EWT +
LAT (DB) = EAT (DB) -
LC = TC - SC
S/T =
HR
gpm x 500
SC
cfm x 1.08
SC
TC
LWT = EWT -
LAT = EAT +
TH = HC + HW
HC
cfm x 1.08
Notes to Performance Data Tables
The following notes apply to all performance data tables:
• Performance ratings are based on 80°F DB/67°F WB EAT for cooling and 70°F DB EAT for heating.
• Three flow rates are shown for each unit. The lowest flow rate shown is used for geothermal open loop/well water systems with a minimum
of 50°F EWT. The middle flow rate shown is the minimum geothermal closed loop flow rate. The highest flow rate shown is optimum for
geothermal closed loop systems and the suggested flow rate for boiler/tower applications.
• The hot water generator numbers are based on a flow rate of 0.4 gpm/ton of rated capacity with an EWT of 90°F.
• Entering water temperatures below 40°F assumes 15% antifreeze solution.
• For non-standard EAT conditions, apply the appropriate Correction Factor tables.
• Interpolation between EWT, gpm, and cfm data is permissible, extrapolation is not.
Affinity & Affinity Advanced Series
1 - 6 Tons 60Hz
SD2500AK6 06/21
19
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