Danfoss Thermostats RT 103, RT 140, RT 141 Installation Guide

Overview

This document provides installation and setting instructions for Danfoss Thermostats, specifically models RT 103, RT 140, and RT 141.

Key Specifications:

• Ambient Temperature Range: -50 °C to 70 °C
• Maximum Sensor Temperatures:
  • RT 103: 100 °C
  • RT 140: 240 °C
  • RT 141: 250 °C

Installation

To ensure the required enclosure protection grade (IP66 for units with automatic reset, or IP54 for units with external reset), a Pg13.5 cable gland, provided separately with the thermostat, must be assembled as shown in Figure 3. If the cable gland is not used with a cable, a metal blanking plug should be installed.

Figure 3 Description: Illustrates the correct method for attaching the Pg13.5 cable gland to the thermostat enclosure for IP66/IP54 protection. Shows gland attachment and the alternative of using a metal blanking plug.

Setting

The thermostat is set according to the desired function (circuit closing or opening) that should occur when the temperature drops (range setting).

Figure 4 Description: Presents a nomogram used for setting the differential. It features temperature scales (in °C) and numbered points (1-11) that correspond to differential settings. The axes are labeled 'A' and 'B', with 'A' typically representing the setting temperature and 'B' the differential.

Setting Procedure (Refer to Figure 4):

• A. Range Setting: Adjust the thermostat by rotating the knob (5), simultaneously reading the main scale (9).
• B. Differential Obtained: (Indicated by the nomogram)
• C. Differential Setting: Adjust the differential using the adjusting nut (19) to the value indicated by the nomogram in Figure 4. The maximum operating pressure is the sum of the setting temperature and the differential.

Example: Controlling an Air Heater with RT 103

Scenario: Control an air heater using an RT 103 thermostat.

• Maximum discharge temperature: 32 °C
• Minimum discharge temperature: 30 °C
• Differential: 32 °C - 30 °C = 2 °C

Steps:

1. Connect the air heater to terminals 1-2 of the thermostat.
2. Set the thermostat to 30 °C by rotating the knob (5).
3. Set the differential adjusting nut (19) to the value indicated by the nomogram for RT 103 in Figure 4 (which corresponds to a 2 °C differential in this example).

Diagram Descriptions

Figure 1 Description: Shows a visual representation of the RT 101 thermostat model.

Figure 2 Description: Displays electrical connection diagrams for the RT 103 and RT 140 thermostats. It shows terminal layouts and electrical ratings, such as AC 110A, DC 13 4A, AC 15 3A 230V, and 24V 25VA a.c.d.c.