Digital Thermostat Installation in RV HVAC Systems

Coleman Mach to Hunter Digital Thermostat Instructions

Credit given where credit is due: This page written by Ken Lenger and derived from the text from Alan Paskey and Les Adams. Credit for the original concept and details of the Coleman modification is given to Alan Paskey. Les Adams further developed this concept to work with the Dometic A/C and Atwood furnace. Their comments follow page 2.

The Coleman Mach analog RV thermostat can be replaced with a Digital Hunter thermostat part number 42999(B) or 42995 to provide tighter temperature control in both heating and cooling modes. The hysterisis program for the Hunter thermostat is +/-1 degree of set temperature, and also provides a digital readout of ambient temperature. The Hunter unit can be purchased from Wal*Mart for about $20. I have also verified that this mod will work with the Lux TX500 thermostat, which is available at many hardware stores.

Although the Hunter thermostat is designed to work with mili-volt and 24 vac residential HVAC systems, it can be used in an RV DC system because the thermostat uses battery power to run all of the thermostat electronics, which in turn controls internal relays to run the heating and air- conditioning equipment.

Function

Coleman Mach

Hunter P/N 42999 or 42995

Wire Color

Terminal Designation

 

+12 VDC Power

Red

RH and RC (Note 1)

DC Ground

Blue

Not Connected (Note 2)

Furnace (+12 VDC switched)

White

W

 

 

 

Fan High (+12 VDC switched)

Green

G (see Note 3)

 

 

 

Fan Low (+12 VDC switched)

Gray

G (see Note 3)

A/C Comp (+12 VDC switched)

Yellow

Y

Note 1: The +12 VDC wire is required because the Hunter thermostat switches this power through switches and relays to operate the HVAC equipment. The RH terminal supplies power to the heating equipment and the RC terminal supplies power to the air conditioning equipment.

Note 2: The DC ground wire is not used. On the Coleman Mach thermostat, power to operate the electronics is derived from RV +12 VDC power. The +12 VDC power and DC ground were required for this. Since the Hunter thermostat uses battery power to operate it’s electronics, the DC ground wire is not required.

Note 3: There are three options for the fan control terminal wiring:

Option 1: The G terminal can be connected to the green wire removed from the Coleman thermostat for manual high speed fan operation, or to the gray wire for low speed fan operation. Option 2: The G terminal can be connected through a SPDT switch to select either high or low speed.

Option 3: The G terminal can be connected through a relay so that the fan runs on low speed whenever the fan is turned on with the FAN switch on the T-stat (G terminal), and runs at high speed whenever the A/C compressor is running (Y terminal). This option allows you to run the fan at low speed to circulate air, but still have the A/C run at maximum capacity when on.

Note 4: The HG / HE switch in the T-stat should be left in the HG position. In the HG (heat-gas) position, the furnace fan is controlled by the furnace electronics. In the HE (heat-electric) position, the Hunter thermostat controls the furnace fan independently of the furnace burner.

This document can be found at http://www.klenger.net/arctic-fox/hunter-tstat/

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Hunter Fan 42999, 42995 manual Coleman Mach to Hunter Digital Thermostat Instructions
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42999, 42995 specifications

The Hunter Fan Company is known for its commitment to quality, innovation, and design in the ceiling fan market. Among its notable offerings are the Hunter Fan models 42999 and 42995, two exceptional ceiling fans that blend aesthetics with functionality.

The Hunter Fan 42999 features a contemporary design that is both stylish and versatile, making it suitable for a variety of home decors. This model comes equipped with a powerful WhisperWind motor that offers ample airflow while operating quietly, ensuring a serene environment in living spaces. In addition, the fan is designed with a three-speed setting, allowing users to optimize air circulation according to their comfort needs.

One of the standout features of the 42999 is its reversible motor. This technology allows for year-round use by enabling the fan to circulate air in both clockwise and counterclockwise directions. In summer, it provides a cool breeze, while in winter, it helps to evenly distribute warm air, improving heating efficiency and comfort.

Similarly, the Hunter Fan 42995 model captures the essence of elegant design with its coastal style. This fan is also equipped with the WhisperWind motor, ensuring a quiet operation, which is particularly beneficial in bedrooms and other tranquil spaces. The 42995 features a beautiful wood finish that adds a touch of sophistication to any room.

Both fans are designed with user-friendly features, such as the easy-to-install mounting system and compatibility with Hunter's wide array of light kits, allowing homeowners to customize their lighting options. The fan blades are crafted from durable materials, and their unique design minimizes wobbling, ensuring stability during operation.

Energy efficiency is a significant consideration in both models. They are designed to operate effectively while consuming less energy, making them an eco-friendly choice for conscious consumers. Furthermore, the Hunter Fan brand is committed to sustainability, incorporating recyclable materials in their manufacturing processes.

Overall, the Hunter Fan 42999 and 42995 models represent a harmonious combination of style, performance, and technology. They provide homeowners with reliable airflow and design flexibility, making them a worthy investment for enhancing comfort and aesthetic appeal in any room.
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