Constant Airflow Motor; Dps Water Flow Proving; Pump Relay; Comfort Alert Module - Bosch SM024 Installation, Operation And Maintenance Manual

38 | Options
The heat exchanger is rated for use with potable
water and is acceptable for use as a domestic
water heating device in most building codes.
The pump circulates water between the domestic
hot water tank and HRP heat exchanger in the Heat
Pump. The control circuit ensures that the HRP
only operates when there is available heat from the
compressor and when the water is within a safe
temperature range of below 140 deg F.
When the heat pump compressor operates, the
HRP will monitor the temperature of the discharge
gas from the compressor. Once discharge gas is
hot enough to provide useful heat to the domestic
water tank, the circulating pump will be enabled,
drawing water from the tank, through the HRP heat
exchanger and then depositing the heated water
back into the tank. If the water temperature
reaches 140 deg F, the circulating pump is
disabled to prevent over heating of the domestic
water. The HRP is provided with an on/off switch
in case the end user desires that the HRP be
inactivated (typically during the winter months
when space heating is most important).
NOTE: If heat recovery unit is installed in an
area where freezing may occur, the unit
must be drained during winter months to
prevent heat exchanger damage. Heat
exchanger ruptures that occur due to
freezing will void the heat recovery package
warranty along with the heat pump
warranty.

Constant Airflow Motor

The Constant Airflow Motor is an Electronic
Commutated Motor (ECM) that provides a
constant air flow over a wide range of external
static pressures, while optimizing the power
consumption of the motor.
This option allows the unit to have different air
flow settings depending on the mode that the unit
is operating; i.e heating, cooling, fan only, hot gas
reheat, etc. Refer to the ECM Interface Board
section (pg.35) for more information.

DPS Water Flow Proving

The DPS water flow proving switch is a factory
installed option available for the SM series. The
DPS prevents compressor operation if there is
inadequate water flow through the water to
refrigerant heat exchanger in the heat pump.
The DPS operates by monitoring the water side
pressure drop across the water to refrigerant heat
exchanger. When the pressure drop between the
water in and water out lines reaches a pre-set
value, compressor operation is enabled.
6 720 220 406 (2015/02)

Pump Relay

The factory installed pump relay can be used to
energize a supply pump or solenoid valve when
there is a call for compressor operation. This relay
can be used to switch either high or low voltage
power.

Comfort Alert Module

The Comfort Alert diagnostics module (CADM) is a
breakthrough innovation for troubleshooting heat
pump system failures. (Figure #105)
By monitoring and analyzing data from the
compressor and the thermostat demand, the
module can accurately detect the cause of
electrical and system related failures without any
sensors. A flashing LED indicator communicates
the ALERT code and guides the service technician
more quickly and accurately to the root cause of a
problem.
This module does not provide safety protection!
The Comfort Alert module is a monitoring device
and cannot shut down the compressor directly.
When an abnormal system condition occurs, the
Comfort Alert module displays the appropriate
ALERT and/or TRIP LED.
The yellow ALERT LED will flash a number of times
consecutively, pause and then repeat the process.
To identify a Flash Code number, count the
number of consecutive flashes.
Every time the module powers up, the last ALERT
Flash Code that occurred prior to shut down is
displayed for one minute.
Subject to change without prior notice
SM Series Heat Pump
Figure # 105
SM Series Heat Pump