Rinnai Pro Series Operation Manual page 9

Cooling cycle
When operating in COOL mode, the system will run until the indoor temperature is lowered to the
level selected. On extremely hot days the system will run for longer periods and have shorter 'off'
periods than on moderate days.
The following conditions add extra heat and/or humidity to your home causing your system to work
longer to maintain comfortable conditions.
• Entrance (external) doors are frequently opened and closed
• More than the usual number of people
• Operating laundry appliances or running showers
• Window furnishings open on sunny side of home
• More than the usual lights or electrical appliances operating
• System operating at or outside the original system design
Defrost cycle
When the system provides heating to your home and the outdoor temperature drops below
7.2 °C, moisture may begin to freeze on the surface of the outdoor coil. If allowed to build up,
this ice would impede the airflow across the coil and reduce the amount of heat absorbed from
the outside air. To maintain energy efficient operation the Rinnai system has an automatic defrost
cycle.
The defrost controls will automatically start when there is sufficient ice to interfere with normal
heating operation. During defrost the indoor fan will not be running. After the ice has melted, or
after a maximum of ten minutes in defrost mode, the unit will automatically resume normal heating
operation.
Do not be alarmed if steam or fog appears at the outdoor unit during the defrost cycle. Water
vapour from melting ice may condense into a mist in the cold outdoor air.
Zoned systems
Some home systems are designed to operate on a zoned basis only. A zoned system will be
designed by your installer for your specific requirements. With zoned systems always observe the
following:
• The return air grille(s) are generally in the common zone and need to be part of the conditioned
space at all times.
• Close off all doors to areas that are not being conditioned, i.e. effectively isolate unconditioned
spaces.
• Set your zoning configuration with zone controls before starting your Rinnai system.
• Do not attempt to shut down more zones than the minimum as specified by your installer as
this may lead to the system shutting down.
• Do not attempt to heat or cool more zones than the maximum specified by your installer as this
will prevent the system from operating correctly.
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