Lennox International Inc. Electric Cooling Package Unit (2/4)SA13 User Manual
Page 7
# 48392M005
Page 7
OPERATION
Sequence of Operation
Cooling
Upon cooling demand, the thermostat closes circuit R and Y.
Closing R and Y closes the unit contactor, starting the
compressor and outdoor fan. The thermostat automatically
closes R to G circuit which also brings on the indoor blower at
the same time. Upon satisfying cooling demand, the thermo-
stat will open the above circuits and open the main contactor,
stopping the compressor and outdoor fan. If the unit is
equipped with a delay timer, the blower will continue to
operate for 90 seconds which improves system efficiency.
Circulating Air Blower
The circulating air blower is controlled by a timing circuit in the
blower control. Timings are not adjustable.
There is no blower “on” delay after a call for heating or
cooling. Blower “off” delay is 90 seconds after the thermo-
stat is satisfied.
Cooling System Performance
For maximum performance of the cooling system, operat-
ing temperatures and pressure should be checked. Super-
heat should be determined at Standard ARI test conditions
of 82°F outdoor and 80°F indoor dry bulb/67°F wet bulb. If
superheat measured deviates from values found in Table 3,
refrigerant charge should be adjusted accordingly for
maximum performance.
Suction Superheat
Table 3
e
z
i
S
t
a
e
h
r
e
p
u
S
n
o
i
t
c
u
S
s
n
o
i
t
i
d
n
o
C
I
R
A
@
B
W
D
I
°
7
6
/
B
D
D
I
°
0
8
-
D
O
°
2
8
2
2
R
A
0
1
4
4
2
°
2
2
°
5
1
0
3
°
0
2
°
5
1
6
3
°
0
2
°
2
1
2
4
°
0
2
°
2
1
0
6
,
8
4
°
0
2
°
0
1