R3 Q1 Flashcards
Refrigeration parameters
ETD 10-20
CTD 20-30-35max
CSH 8-12
SSH min 20
SC 5-20
High temp
+40
HVAC
Medium temp
+20
Coolers
Low temp
-20
Freezers
Electrical start components
PSR
CSR
PTC
Potential relay
5k-15k ohms
BEMF
Pick up point
75%
Current start relay
L-line
M-main
S-start windings
Positive temp coefficient
Used on Fractional Hp units
Temp control
Lpc
Installed higher then comp
Single circuit Evaps
One circuit from txv to comp
Internally and externally txv
Multi circuit
Prevent pressure drop
Externally equalized txv only
DX
Direct expansion
Fin spacing
+40 high
+20 medium ( off cycle, electric heat)
-20 least ( electric, hot gas)
Off cycle defrost
1 cycle for 60 min in 24 hour
Electric defrost
2 cycles 30 min in 24 hours
Hot gas cycle
4 cycles in 15 min in 24 hours
Voltage imbalance
1 add all voltage
2 calculate average
3 subtract average from each voltage
4 identify greatest deviation
5 divid deviation by average
6 multiply by 100
Txv
