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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 reconnecting 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 reconnecting 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 reconnecting the harness to the control.
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 “i” 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 “i” 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: @ 77°F
(25°C), E = 3892
* POC #3 Control Only
** POC #2 & #3 Controls Only
Temperature Resistance Temperature Resistance Temperature Resistance Temperature Resistance
ºF ºC
:
ºF ºC
:
ºF ºC
:
ºF ºC
:
-50 -46 490,813 20 -7 46,218 90 32 7,334 160 71 1,689
-40 -40 336,606 30 -1 34,558 100 38 5,828 170 77 1,403
-30 -34 234,196 40 4 26,099 110 43 4,665 180 82 1,172
-20 -29 165,180 50 10 19,900 120 49 3,760 190 88 983
-10 -23 118,018 60 16 15,311 130 54 3,050 200 93 829
0 -18 85,362 70 21 11,883 140 60 2,490 210 99 703
10 -12 62,465 80 27 9,299 150 66 2,045 220 104 598
Table 6.4: Sensor Resistance Tables