INSTALLATION MANUAL AND OPERATING INSTRUCTIONS
Sequence of Operation
DPM-2 is designed to operate in conjunction with several
Argo controls via a ribbon cable but may also be used with
other manufacturers’ controls� The following assumes the
application is a ribbon cable to standard zone control�
1.
Zone control and boiler should be functioning properly
in all respects prior to evaluating the DPM-2� Remove
the ribbon cable and verify proper system operation
before continuing�
2.
Connect the DPM-2 to the zone control using the
supplied ribbon cable in accordance with the wire
diagram for your specic application (See Section VIII
of this manual for examples�)
3.
With the DPM-2 “Power On” switch in the “On” position,
there should be 24 VAC across the lower terminals
labeled “24 VAC and Common.”
4.
The high limit control on the boiler should be set to a
higher temperature than the “Max. Temp.” setting on
the DPM-2. (See Section VII for more information.)
5.
The “Priority On” LED should be on when the “Priority
Zone” terminals on the zone control are jumped.
The small relay near the LED should also be heard
energizing�
6.
When the DPM-2 “Reset On” LED is illuminated, the
X-X relay on the zone control should be o. When the
“Reset On” LED is o, the X-X relay should be on only
if a zone is calling for heat�
RTD Sensor Troubleshooting
To conrm RTD Sensor is functioning properly:
1.
Remove both RTD leads from the terminal block on the
control board�
2.
Use a multimeter to take an ohm reading across the
RTD leads� A properly functioning RTD Sensor will
produce a reading of approximately 1005 ohms at 70°F
while a faulty RTD will read either “0” or “1.”
3.
Replace RTD if necessary�
Troubleshooting Tips
1.
If the setup check is okay, a problem may be due to a
faulty sensor, faulty installation, or faulty wiring�
2.
Disconnect the sensor wires from the DPM-2 terminals
and measure the resistance between the wires� The
measured resistance should be within 5% of the values
in the table below� If the meter indicates an open or
short you might suspect the wiring between the sensor
and the DPM-2�
3.
If the outdoor sensor disagrees with another outdoor
thermometer, it may be located in direct sunlight�
Reposition the sensor if necessary� Do not proceed
until both sensors are performing properly�
EXAMPLE: If the water sensor reads 1500 ohms and you
estimate the water is about 175°F, the water sensor is
okay. If the meter reads 1400 ohms or 155°F, you might
suspect the thermal connection between sensor and the
pipe.
OUTDOOR SENSOR WATER SUPPLY SENSOR
Degrees Ohms Degrees Ohms
5 758 149 1368
14 789 158 1413
23 822 167 1459
32 855 176 1506
41 889 185 1554
50 924 194 1602
59 960 203 1652
68 997 212 1702
77 1035 - -
NOTE: The Outdoor Sensor and Water Supply Sensor
are interchangeable and may be reversed to assist the
troubleshooting process.
10
PN 240005132 Rev. D [11/15/2021]
