Rheem 325 II Series Service Instructions Manual page 14

SYSTEM START-UP
When power is first applied to the system, a 3 second System Start-Up process occurs.
During the 3 second System Start-Up, the green LED displays a rapid flash and the
element operates.
If a fault occurred during the last operation of the heat pump, a Fault Code will have been
stored. If a Fault Code is stored, that Fault Code will be displayed for 27 seconds after the
green LED‟s rapid flash, to indicate the last fault that occurred. See the LED Status Codes
section on page 18.
The element is energised if the red LED is displaying a stored Fault Code.
STANDBY MODE
Standby is an idle mode where power is available, but water heating is not required. The
green LED is illuminated and remains on.
The Freeze Protection function may be required whilst in Standby Mode, refer to the
Freeze Protection section on page 17.
HEAT PUMP MODE
Heat pump heating is initiated when the tank sensor detects a temperature less than 50°C.
Should the ambient temperature be outside the heat pump‟s operating limits or a fault is
detected, the system may switch to Element Mode at any stage during Heat Pump Heating
– see the Element Mode section on page 15.
Heat Pump Mode consists of three stages – System Check, Heat Pump Pre-Heating and
Heat Pump Heating.
System Check
During system check, the green LED will display one flash.
If the compressor sensor detects a temperature greater than 60°C, the system will
remain in Standby Mode until the compressor has cooled.
The controller checks that the 45 minute start delay has elapsed. The start delay may
have already elapsed, as it begins from the last compressor shut down. To begin the
start delay, the control system requires that power is available. The start delay does
not occur when power is applied to a new system for the first time.
Once the compressor has cooled and the start delay has elapsed, the system goes
to Heat Pump Pre-Heating.
The Freeze Protection function may be required whilst in System Check, refer to the
Freeze Protection section on page 17.
Heat Pump Pre-Heating
During Heat Pump Pre-Heating, the green LED will display 2 flashes.
The compressor and fan operate, and the circulator is initially off. The controller checks the
heat exchanger water outlet temperature every 30 seconds and when the heat exchanger
water outlet temperature is greater than 22°C, the circulator starts at its pre-set initial
speed.
TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
This document is stored and maintained electronically by Service. All printed copies are deemed uncontrolled.
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