Mermaid Air Conditioner - Manual (Page 31)

on any other remaining lead along the black terminal board – WHITE, BLACK, OR
GREEN.
h) If 24 vac is present and all of the above checks and procedures are positive, most
likely the thermostat is faulty or a wire has loosened inside the electrical box. To check
the thermostat, take a 5 or 6 inch piece of insulated wire, strip the insulation back about
1/8 inch on each end and use it to short the "RED" wire to the "BLACK" wire on the
BLACK terminal board. If the unit immediately comes on, the thermostat is faulty and
needs replacing. If the unit does not operate, the problem is in the electrical box.
i) If 24 vac was not present in step g) above, most likely the transformer inside the
electrical box is faulty or a wire has loosened inside the box.
Note: Once a problem has been isolated to the internal portion of the electrical box,
the box must now be opened. Before preceding further, you must disconnect all 115
(220) vac electrical power to the boat. (SEE WARNING BELOW)
WARNING
IF ALL 115 VAC POWER IS NOT DISCONNECTED FROM THE BOAT YOU
MAY INCUR ELECTRICAL SHOCK WHICH CAN CAUSE SERIOUS INJURY
OR DEATH.
j) After you have removed all 115 (220) vac electrical power, the electrical box cover
may be removed by removing the three retaining screws on each side of the box. Once
the screws are removed the cover will slide off the box.
k) Closely check the box for loose or disconnected wires. If all wiring is tight and in
place, replace the transformer. A new transformer may be purchased from your nearest
Mermaid dealer, refrigeration supply store or direct from the Mermaid factory.
2. Standard 24v Thermostat In COOL Position - Fan Runs - Compressor Does Not:
a) Place thermostat in the OFF position. Locate the HIGH PRESSURE switch mounted
on the top of the air conditioner unit. Check if the red button is active or extended. If the
pin is extended, push it in. This switch shuts power off to the compressor when cooling
water is insufficient to make the required heat exchange as described in Theory Of
Operation above. Check water pump for prime and motor operation, check raw water
strainer for clogging and hoses for kinks. Fix water problem and turn thermostat back
on.
b) If water pump is operational and HIGH PRESSURE switch has not activated, perform
thermostat jumper test described in paragraph 1h) above. If unit operates, replace
thermostat batteries and/or thermostat.
3. Compressor Runs - Fan Does Not: