PM-2B Installation Manual
IS-WR-PM2B
Instructions for Installing PM-2B
Remote Snow/Ice Sensor
The PM-2B is a multi-voltage, self contained temperature, snow and ice
sensor control. Each PM-2B can be set to operate with either 120 , 208,
or 240 VAC and can provide up to 30 amps of service to the load. The
integrated snow sensor is heated to allow for snow, ice, or freezing rain to
melt, allowing proper detection of environmental conditions.
Installation
The PM-2B must be installed in a location that exposes the moisture grid
to a clear view of the sky and any precipitation. The unit should not be
mounted directly under eaves, overhangs, or other obstructions that can
block precipitation from reaching the moisture grid.
Do not install the sensor close to the ground, or any other location, that can
cause the sensor to be buried in snow.
Mount the PM-2B outdoors, away from furnace vents, dryer vents, and
other sources of heat. The PM-2B can be mounted to a free-standing
conduit or by using the mounting holes in each corner of the enclosure.
Do not drill holes in the enclosure.
Wire the controller in accordance to the provided schematics.
Operation
Before installing and wiring the
PM-2B sensor, it is important to set
all power and control settings prior
to wiring or mounting.
1. Set the voltage jumpers
to correspond with the
supplied power. Place
jumpers on the outside two
posts for 120 VAC and a single
jumper on the inside two posts
for 240 VAC.
2. Set the Temp Adjust
control for desired melting conditions. Precipitation
below this temperature
is assumed to be snow, above rain. Control comes
with the Temp Adjust dial set to 39°F (4°C).
3. Set the Delay (DEL) time for 30, 45, 60, 75, or 90
minutes. The Delay function will allow the snow melt system to run for
the set time frame after moisture is no longer detected (once snowfall
has stopped). This is to help prevent "black ice" from forming.
4. Determine how the sensor operates by setting the toggles located
at S1.
Snow: The control will operate when
precipitation is detected below the
Temp Adjust setting. Recommended ON.
Rain: The control will operate when precipitation is
detected above the Temp Adjust setting. Required OFF.
DEL: The control will operate with a Delay Off time. If this
function is set to Off, the control will operate with a 2 minute delay
to prevent short-cycling of external components.
Recommended ON.
LTC: The control will operate in Low Temperature Cutoff mode,
preventing operation when Ambient Temperatures (AT) fall
below 15°F (9.5°C).
Recommended: ON (for systems with limited heat output).
Power must be cycled for switch changes to take effect.
Manual Override Switch
An override switch is mounted on the side for testing and special
operational requirements. Placing the switch in the "Automatic" position
will allow the sensor to operate normally. "Manual On" will activate the
control and will stay activated for a maximum of 40 hours before returning
to "Automatic" mode. The "Stand-by/Reset" position will clear any current
snow melt call or delay activity.
If the Manual Override Switch is moved to Manual On for less than
2 seconds and then back to Automatic the sensor will execute one delay
off cycle. This can be used to clear frost, hail, drifting snow, or other
conditions. Stand-by/Reset will clear this setting.
IND. CONT. EQ.
LISTED
11TN
USC
R
ENCLOSURE TYPE 3R
PM-2B provides integrated air and moisture detection within a
rainproof and ice-resistant enclosure.
Air Temperature Sensor
Wiring Access
Control Switch
Moisture Grid
Manual
On
30Min
45
60
75
90
Manual
On
30Min
45
60
75
90
Manual
On
30Min
45
60
75
90
Manual
On
30Min
45
60
75
90
Manual
On
30Min
45
60
75
90
!
WARNING: General Safety Instructions
1. THIS UNIT SHOULD BE INSTALLED ONLY BY
QUALIFIED PERSONNEL!
2. Disconnect all power from the control, or any associated equipment,
before opening the front cover plate.
3. Confirm power selection jumpers are properly set prior to
applying power.
4. To avoid fire hazard, replace fuse only with 2 Amp 32 V or 250 V 3AG
fast acting fuse.
5. Do not drill holes through the electrical enclosure for mounting.
Mount the control to a free-standing conduit or via the pre-determined
mounting holes.
6. Ensure front cover gasket is properly installed when replacing cover.