R e m o t e H W G
R e v i s e d : M a rc h 1 2 , 2 0 1 9
8
G e o t h e r m a l H e a t P u m p S y s t e m s
Hot Water Generator
WARNING!
WARNING!
C
H
M
WATER HEATER
CHECK VALVE
8”
M
AX
HOT WATER
TO HOUSE
ANTI-SCALD
VALVE
ANTI-SCALD
VALVE PIPING
CONNECTIONS
COLD WATER
SUPPLY
Anti-Scald
Valve Piping
Connections
Alarm
Relay
Comp
Relay
24Vdc
EH1
EH2
P6
Off On
JW3
A
OVR
ESD
C
R
NSB
AL2
JW1
Acc1
Relay
Acc2
Relay
H
COM1
NC1
NO1
COM2
NC2
NO2
P3
CO
RV
RV
LT1
LT1
LT2
LT2
LP
LP
HP
HP
P7
Status
Fault
R
R
CC
CCG
CO
S1
S2
1
12
1
4
e
s
U
yr
ot
c
a
F
Micro
U1
Off On
P2
COH
COM
AO2
P11
Gnd
T1
P10
T2 T2 T3
T3 T4 T4
T5
P9
T5 T6 T6
A0-1 A0-2
Off On
S3
RV
Relay
CCH
Relay
Gnd
NC
1 2 3 4
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
Hot Water
Generator
Settings
Figure 5: Hot Water Generator Settings
Installation
The HWG is controlled by two sensors and the DXM2 micro-
processor control. One sensor is located on the compressor
discharge line to sense the discharge refrigerant tempera-
ture. The other sensor is located on the HWG heat exchang-
er’s “Water In” line to sense the potable water temperature.
The DXM2 microprocessor control monitors the refrigerant
and water temperatures to determine when to operate
the HWG. The HWG will operate any time the refrigerant
temperature is su
ffi
ciently above the water temperature.
Once the HWG has satis
fi
ed the water heating demand
during a heat pump run cycle, the controller will cycle the
pump at regular Intervals to determine if an additional HWG
cycle can be utilized.
When the control is powered and the HWG pump output is
active for water temperature sampling or HWG operation,
the DXM2 status LED will slowly
fl
ash (On 1 second, O
ff
1
second).
If the control has detected a HWG fault, the DXM2 status
LED will
fl
ash a numeric fault code as follows:
High Water Temperature (>160ºF)
5
fl
ashes
Hot Water Sensor Fault
6
fl
ashes
Compressor Discharge Sensor Fault
6
fl
ashes
Fault code
fl
ashes have a duration of 0.3 seconds with
a 10 second pause between fault codes. For example, a
“Compressor Discharge sensor fault” will be six
fl
ashes 0.3
seconds long, then a 10 second pause, then six
fl
ashes
again, etc.
Hot Water Generator settings are determined by DIP
switches 3-2, 3-3, and 3-4.
DIP 3-2 controls the HWG Test Mode. It provides for forced
operation of the HWG output, activating the HWG pump for
up to
fi
ve minutes. ON = HWG test mode, OFF = normal
HWG operation. The control will revert to standard operation
after
fi
ve minutes regardless of switch position.
DIP 3-3 determines HWG set point temperature. It provides
for selection of the HWG operating set point. ON = 150°F
(66°C), OFF = 125°F (52°C).
DIP 3-4 is for the HWG status. It provides HWG operation
control. ON = HWG mode enabled, OFF = HWG mode
disabled. Units are shipped from the factory with this switch
in the OFF position.
WARNING! USING A 150°F SETPOINT ON THE
HWG WILL RESULT IN WATER TEMPERATURES
SUFFICIENT TO CAUSE SEVERE PHYSICAL INJURY
IN THE FORM OF SCALDING OR BURNS, EVEN WHEN
THE HOT WATER TANK TEMPERATURE SETTING
IS VISIBLY SET BELOW 150°F. THE 150°F HWG
SETPOINT MUST ONLY BE USED ON SYSTEMS THAT
EMPLOY AN APPROVED ANTI-SCALD VALVE (PART
NUMBER AVAS4) AT THE HOT WATER STORAGE
TANK WITH SUCH VALVE PROPERLY SET TO
CONTROL WATER TEMPERATURES DISTRIBUTED
TO ALL HOT WATER OUTLETS AT A TEMPERATURE
LEVEL THAT PREVENTS SCALDING OR BURNS!
WARNING! UNDER NO CIRCUMSTANCES SHOULD
THE SENSORS BE DISCONNECTED OR REMOVED.
FULL LOAD CONDITIONS CAN DRIVE HOT
WATER TANK TEMPERATURES FAR ABOVE SAFE
TEMPERATURE LEVELS IF SENSORS DISCONNECTED
OR REMOVED.
