Honeywell Design and Application User Manual

Section 13 - Checkout
63-8594-02 Honeywell Economizers 170
Check out C7400 with W7459, W7210 and W7212:
You can check if the C7400 is within the RH
and temperature range with the W7212 logic
module using the following method.
• Make sure the sensors are all connected to
the logic module.
• To check the return air C7400 sensor on Sr
and Sr+: Measure the voltage across Sr and
Ground.
• To check the outdoor air C7400 sensor on
So and So+: Measure the voltage across So
and Ground.
• You must have an accurate reading of the
temperature and humidity.
• Find the line on the chart on this slide for
return air C7400 sensor that corresponds to
the voltage you read across Sr and ground.
It should intersect with the humidity and
temperature of your conditions.
• There is a ± 0.3 Vdc range for the sensor
accuracy and above 90% RH the accuracy
changes to ± 0.4Vdc.
The lines and chart for the So C7400 sensor
are slightly different. The reason is for a
differential of the sensor inputs to the logic
modules for a choice between the two sensors
for differential enthalpy. To assure accuracy in
reading these charts, which are small, a table
is provided on the following page for ease of
use.
40
(4)
50
(10)
(21)
80
(27) (32)
10
90
80
PERCENT
RELATIVE
HUMIDITY
60
(16)
70 90 100
(38)
70
60
50
40
30
20
TEMPERATURE ºF (ºC)
C7400 SO AND GND VDC
1.0 VDC
1.5 VDC
4.4 VDC
3.9 VDC
3.4 VDC
2.4 VDC
2.9 VDC
1.9 VDC
4.9 VDC
+/- .4VDC
>90% RH
4181614 12 10 8 620
SO C7400 CHECK
+/- .3VDC
<90% RH
M23991A
40
(4)
50
(10)
(21)
80
(27) (32)
10
90
80
PERCENT
RELATIVE
HUMIDITY
60
(16)
70 90 100
(38)
70
60
50
40
30
20
TEMPERATURE ºF (ºC)
C7400 SR AND GND VDC
1.0 VDC
1.5 VDC
4.6 VDC
4.1 VDC
3.6 VDC
2.6 VDC
3.1 VDC
2.0 VDC
5.1 VDC
+/- .4VDC
>90% RH
4181614 12 10 8 620
SR C7400 CHECK
+/- .3VDC
<90% RH
M23990A

Honeywell Design and Application Specifications

General

Brand	Honeywell
Model	Design and Application
Category	Controller
Language	English