Retrotec DM32 - Manual (Page 10)

Page 10 of 94
©Retrotec Inc. 2014
2. Gauge overview
The front of the gauge has a resistive touchscreen, a touch-sensitive [Home] button , and a battery
charge indicator light. Because the screen is resistive, it can be operated when the user is wearing gloves,
and in most environmental conditions.
The top of the gauge has four color-coded pressure tube ports, and a Control output port (for fan speed)
The bottom of the gauge has an Ethernet network port (for gauge-computer communications), a USB port
(mainly for battery charging), and a Reset button (recessed, accessible using a paper clip).
The touchscreen serves as both the information display and the keypad for the gauge. The information
displayed depends on selections a user makes by tapping on the touch sensitive areas on the screen, called
“keys” in this manual and shown in square brackets [].
2.1 Make connections to the gauge
Physical connections from the gauge to a calibrated fan are on top of the gauge. Physical connections to a
computer or power adapter are on the bottom of the gauge.
An Ethernet-style cable from the fan speed output control port connects to a calibrated fan to control its
speed. The cable supplied for this purpose with Retrotec systems is yellow.
Pressure tube ports on the top of the gauge are color-coded to distinguish where pressure tubes are
connected. Retrotec has a specially designed pressure tube port that grips pressure tubes well, but
releases them without tearing after long-term use. This exclusive connector is designed by Retrotec to
make contact with the both tube internally and externally with a shallow taper.
Figure 2: Connect tubes and Speed Control Cable
Table 1: Physical connections from gauge to fan are on top of gauge
gauge port connection
1
“Fan Speed” control cable port
Connect the yellow Retrotec-proprietary Speed Control Cable
2
Blue pressure port: “input B (+)”
Often has no pressure tube connected. For duct testing, a blue pressure tube
leads from the gauge into the ducts.
3
Red pressure port: “ref B (-)”
Connect the red pressure tube from the gauge through the Door Panel to the
outdoors.
4
Yellow pressure port: “ref A (-)”
Connect the yellow pressure tube from gauge to yellow port on a Retrotec fan
5
Green pressure port: “input A (+)”
Connect green pressure tube to green port on Retrotec fan, if applicable. No
pressure tube will be here if Retrotec fan does not have a green pressure port
Pressure tubes should be clean and not stretched in order to make a proper connection. If a pressure tube is
damaged, simply slice a short piece of tube off the end to ensure a clean fit. Tubing can crack in cold weather, but can