Mermaid REFRIGERATION/FREEZER Thermostat type, If you are planning to convert your ice, charge

3	Thermostat type	If you are planning to convert your ice
		box into a freezer, or as a spillover
		system, a freezer thermostat (0021)
		must be used.
4 Evaporator type & size		If the evaporator has an even coating of
		frost, the thermostat is set on 7, & the
		system is cycling, the evaporator may
		be too small. Either replace the
		evaporator with a larger model, add
		insulation to the bottom of the box to
		reduce volume, or re-locate the
		evaporator lower in the box. The latter
		may cause the temperature at the top of
		the box to be above acceptable levels.
5	Excessive frost build-up	If an excessive layer of frost is allowed
		to build up on the evaporator it will act
		as an insulator & adversely affect box
		temperatures. Defrost system by
		interrupting power supply at the breaker
		panel or by turning thermostat to the off
		position. Restore power or reset
		thermostat when evaporator is free of
		frost. Never use any implement in an
		attempt to loosen the frost on the
		aluminum evaporator. A light frost is
		acceptable.
6	Incorrect refrigerant	If, after the compressor has been
	charge	running for an appreciable length of
		time, the evaporator surface does not
		have an even coating of frost, or it is
		only cold & sweating to the touch, the
		system may be low on refrigerant or
		over-charged. Consult a marine
		refrigeration specialist.
7	Drain left unplugged	If your ice-box is equipped with a drain
		in the bottom of the box, it is suggested
		that you block it off to prevent heat
		loss. The drain should only be used if
		you revert to melting ice, or after a
		major clean-up.
8	Tubing hole left	The hole that had been drilled to allow
	unplugged	the copper tubes on the evaporator to
		pass through during installation must be
		sealed.