Dometic MCS T6 Operating Manual page 26

Troubleshooting
Problem
No cooling or heating
(contn'd).
No cooling
No heating.
26
Possible Reason
Fan coil is iced (in cooling).
Fan is not running.
Seawater plumbing is air-locked.
The Marine Climate System is pro-
grammed for Cool or Heat only, or
mechanical control thermostat is
rotated too far towards either Cooler
or Warmer setting.
High pressure switch open (in cool-
ing) due to improper seawater flow.
Strainer or intake may be plugged,
seacock may be closed.
High pressure switch open (in heat-
ing) due to improper airflow.
High-pressure switch is open in heat-
ing mode.
Compressor's thermal overload is
open due to either of the above rea-
sons.
Control panel may not be in "cool"
position.
Coil iced.
Unit is "cool only", or if reverse cycle,
reversing valve may be stuck.
MCS T6, MCS T12, MCS T16
Solution
See below.
See corresponding section in "Con-
trol Panel Troubleshooting" on
page 30.
Ensure that seawater plumbing is
installed per the guidelines in the
Installation Manual.
Set P-1 to the desired value or rotate
the mechanical control thermostat.
Check seawater hose for kinks or col-
lapses.
Verify pump operation.
Check pump circuit breaker if appli-
cable.
Remove any obstructions in return air
stream.
Clean return air filter and grille.
Check for crushed or restricted duct-
ing (ducting must be as straight,
smooth and taut as possible).
System may cycle on high-pressure if
seawater temperature is above
12.8 °C (55 °F).
Compressor needs to cool down.
Turn system off for a while (it may take
up to three hours to reset thermal
overload).
Reset control panel.
See below.
Tap reversing valve lightly with rub-
ber mallet while unit is in heat mode.
Call for service if that does not cor-
rect the problem.
EN