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ELECTRICAL & CONTROLS
-
Using table 6.4, estimate the temperature at
the sensor.
-
If the resistance is much higher than expected,
there may be a broken wire, a poor
connection, or a defective sensor.
-
If the resistance is much lower than expected,
there may be a short in the wiring, moisture in
the sensor, or a defective sensor.
c) Test the Power Supply: Make sure exposed
wires and bare terminals are not in contact
with other wires or grounded surfaces
-
Turn on the power using the boiler service
switch located on the control bezel.
-
Measure the voltage between terminals 12 and
24 on the harness connector (These are the top
two connections on the control and are labeled
on the back of the control) (See Figure 6.2).
-
The voltage should be between 22 and 26 VAC.
-
Turn off the boiler service switch before re-
connecting the harness to the control.
d) Test the Heat Demand: Turn on the boiler service
switch, located on the control bezel.
-
Measure the voltage between terminal (2) Ht D
(Heat Demand) and terminal (1) CD
(Common Demand).
-
When there is a heat demand signal, the
voltage across these terminals should read
between 20 and 260 VAC. When no call for
heat is expected, the voltage should be less
than 5 VAC.
-
Turn off the boiler service switch before re-
connecting the harness to the control.
e) Test the Setpoint Demand: Turn on the boiler
service switch, located on the control bezel.
-
Measure the voltage between terminal (3) Set
D (Setpoint Demand) and terminal (1) CD
(Common Demand).
-
When there is a setpoint demand signal, the
voltage across these terminals should read
between 20 and 260 VAC. When no call for
heat is expected, the voltage should be less
than 5 VAC.
-
Turn off the boiler service switch before re-
connecting the harness to the control.
Temperature Resistance
ºF
ºC
-50
-46
490,813
-40
-40
336,606
-30
-34
234,196
-20
-29
165,180
-10
-23
118,018
0
-18
85,362
10
-12
62,465
Table 6.4: Sensor Resistance Tables
28
Temperature Resistance
ºF
ºC
20
-7
46,218
30
-1
34,558
40
4
26,099
50
10
19,900
60
16
15,311
70
21
11,883
80
27
9,299
f) Test the Control's Output Functions: All POC
controls feature a built-in test routine for testing
the control outputs. The test routine is initiated
when the " " button is pressed in and held in
while in the view menu. The outputs are tested in
the following sequence:
-
Step 1: After 1 second, the boiler circulator is
turned on.
-
Step 2: After 4 seconds, the DHW circulator is
turned on (POC #2 & POC#3 Only).
-
Step 3: After 7 seconds the burner demand is
activated.
-
Step 4: After 10 seconds the second stage
burner is activated (POC #3 Only)
-
Step 5: After 13 seconds, the Alarm terminal is
activated.
-
After the " " button is released, the control
continues normal operation.
L. POC TECHNICAL DATA
Control: Microprocessor based PI control.
Enclosure Material: Black Noryl plastic
Dimensions: 4-3/4 x 2-7/8 x 1-7/8 inches
(120 x 74 x 48 mm)
Approvals: CSA C US, meets ICES & FCC regulations
for EMI/RFI
Ambient Conditions: Indoor use only, -40 to 140°F (-40
to 60°C), <90% Relative Humidity
Power Supply: 24V ±10% 50/60Hz 75 VA
Stage 1 Relay: 120 VAC, 5A 1/6 hp, pilot duty
Circulator Relays: 120 VAC, 5 A 1/6 hp, pilot duty
Stage 2* Relay: 120 VAC, 3 A, 1/6 hp
Alarm** Relay: 24 VAC, 3 A, 1/6 hp
Sensors included – NTC thermistor, 10 k
(25°C),
= 3892
* POC #3 Control Only
** POC #2 & #3 Controls Only
Temperature Resistance
ºF
ºC
90
32
7,334
100
38
5,828
110
43
4,665
120
49
3,760
130
54
3,050
140
60
2,490
150
66
2,045
@ 77°F
Temperature Resistance
ºF
ºC
160
71
1,689
170
77
1,403
180
82
1,172
190
88
983
200
93
829
210
99
703
220
104
598
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Troubleshooting
