Reference Calculations; Legend; Operating Limits - York YAST026 Installation Manual

Reference Calculations

Heating Calculations:
HE
LWT = EWT -
GPM x 500
HC
LAT = EAT +
CFM x 1.08
TH = HC + HW

Legend

ABBREVIATIONS AND DEFINITIONS:
CFM = airfl ow, cubic feet/minute
EWT = entering water temperature, Fahrenheit
GPM = water fl ow 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, MBTUH
TC = total cooling capacity, MBTUH
SC = sensible cooling capacity, MBTUH
KW = total power unit input, kilowatts
HR = total heat of rejection, MBTUH

Operating Limits

Operating Limits
Air Limits
Minimum ambient air, DB
Rated ambient air, DB
Maximum ambient air, DB
Water Limits
Minimum entering water
Normal entering water
Maximum entering water
Normal water flow
Cooling Calculations:
LWT = EWT +
GPM x 500
LAT (DB) = EAT (DB) -
LC = TC - SC
SC
S/T =
TC
Cooling Heating
-10°F [-23.3°C] -10°F [-23.3°C]
80.0 [26.7°C] 70°F [21.1°C]
120 [48.8°C] 85°F [29°C]
30°F [-1°C] 20°F [-6.7°C]
50-110°F [10-43°C] 30-70°F [-1 to 21°C]
120°F [49°C] 90°F [32°C]
1.5 to 3.0 gpm per ton
[1.6 to 3.2 l/m per kW]
AFFINITY DUAL-CAPACITY OUTDOOR SPLIT SERIES INSTALLATION MANUAL
HR
SC
CFM x 1.08
HE = total heat of extraction, MBTUH
HW = hot water generator capacity, MBTUH
EER = Energy Effi ciency Ratio
= BTU output/Watt input
COP = Coeffi cient of Performance
= BTU output/BTU input
LWT = leaving water temperature, °F
LAT = leaving air temperature, °F
TH = total heating capacity, MBTUH
LC = latent cooling capacity, MBTUH
S/T = sensible to total cooling ratio
NOTES: 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.
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