PAGE 10
INSTALLER’S GUIDE
5. Checkout
SINGLE ENTHALPY CHANGEOVER SET POINT
Single enthalpy:
The enthalpy
changeover set point is set to return the
outdoor air damper to minimum posi-
tion when the enthalpy rises above its
set point. The enthalpy set point scale
markings, located on W7459, are
A,B,C,D; see table
for the correspond-
ing control point. The factory-installed
R4 WHITE 620-ohm jumper must be in
place across ter and SR.
Operate the motor through its complete open-close stroke. If
necessary, release one of the previously tightened linkage con-
nections to prevent damage. Check for proper operation, making
sure that the linkage does not bind and that the motor travels
smoothly throughout its fully open and closed position. Table 1
describes how to drive the motor to the full open and full closed
positions (power connected). If there is excess length of linkage
rod, cut it to size. Make necessary minor adjustments until
desired operation is obtained, and tighten all nuts and set screws.
This motor checkout ensures that:
1. The motor operates the load.
2. The motor responds properly to the controller.
3. There is no binding of the linkage or motor stalling at any
point of travel.
If motor does not operate properly, check for proper voltage or
mechanical binding in linkage or damper.
If questions arise regarding this product, contact your distributor
or representative.
CONTROL
CURVE
A
B
C
D
CONTROL POINT
APPROX. F ( C)
AT 50% RH
73 (23)
70 (21)
67 (19)
63 (17)
12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42
44 46
90
100
80
70
60
50
40
30
20
10
ENTHALPY—BTU PER POUND DRY AIR
85
(29)
90
(32)
95
(35)
100
(38)
105
(41)
110
(43)
35
(2)
35
(2)
40
(4)
40
(4)
105
(41)
110
(43)
45
(7)
45
(7)
50
(10)
50
(10)
55
(13)
55
(13)
60
(16)
60
(16)
65
(18)
65
(18)
70
(21)
70
(21)
75
(24)
75
(24)
80
(27)
80
(27)
85
(29)
90
(32)
95
(35)
100
(38)
APPROXIMATE DRY BULB TEMPERATURE— F ( C)
A
A
B
B
C
C
D
D
M11681
RELATIVE HUMIDITY (%)
1
1
HIGH LIMIT CURVE FOR W7459D.
MODEL
DRIVE MOTOR OPEN
DRIVE MOTOR CLOSED
SPRING RETURN
M7415
Power to TR and TR1, jumper T and T1.
Disconnect jumper at T or T1 and
disconnect P or P1,if connected.
Disconnect power at TR and TR1.
Table 1. Motor Operation Checkout
