Mermaid Air Conditioner - Manual (Page 28)

substances shall not be subject to the prohibition set forth in the proceeding sentence."
*Class I substances include CFC-12
**Class II substances include HCFC-22
All Mermaid air conditioners have always been charged with HCFC-22 (R22), similar to
your home air conditioner or refrigerator. CFC-12 (R12) has never been used in
Mermaid air conditioners. It is unlawful for any technician who is not EPA certified as at
least a Type1.
A. THEORY of OPERATION:
1. General:
Note: It is helpful to refer to the Operational Block Diagram, FIGURE 2, and the
Model Wiring Diagrams, FIGURES 4a through 4c, as you read this Theory of
Operation.
All Mermaid "cool only" air conditioning units are controlled and function exactly the
same, regardless of the btu capacity of the unit. Units equipped with a "heat option" are
controlled in the same manner as "cool only" units, but may employ completely different
concepts for producing heat. The digital thermostat is the master control of the system
and dictates the operational mode of the air conditioning unit through an electrical
control box. Though the thermostat has many operational modes, such as operational
programming, time of day, etc., all you need to do to operate the basic functions of cool
and heat is to put the HEAT-OFF-COOL switch in the applicable position and depress
the UP or DOWN ARROW to set the desired temperature.
2. Heating Options:
Mermaid offers two optional types of heating technologies for their units. One option is
"electric heat". This option employs electrical heating coils placed in the path of cabin
return air. Return air is heated as it passes over the electrical coils and is then forced
back into the cabin. The electric heat option is available only on the M-6, M-9 and M-12
Models. The second heat option is a "heat pump". In this option the system freon is
forced to flow through the unit evaporator in a reverse direction heating the evaporator.
Cabin return air is pulled through the evaporator, heating the air as it passes through, and
then forces it back into the cabin. This is the same principal used in many home and pool
heating devices and is also referred to as "reverse cycle" heat. The heat pump option is
available with all the Mermaid models.
3. Electrical:
a) All Mermaid air conditioner models are available in either 115 vac or 220 vac
configurations. Shore power is applied to the air conditioner from the boat’s main circuit