52
KBD Series Manual
Recirculation Mode
Sequence of Operation
SW4 and SW8 in DIPSW 2 should be set correctly for
recirculation and mode. The Rinnai water heater
should be turned on.
Pump recirculation begins when the water heater is
turned on. The Rinnai inlet and outlet thermistors
measure the water temperature.
The water heater produces hot water at the
temperature setting. If the inlet thermistor detects
abnormal temperature then diagnostic code 51 is
generated and the pump will turn off.
When the return water temperature reaches
approximately 15°F (8.3°C) below the temperature
setting, the water heater and pump will turn off.
The cycle will restart at the approximate time interval
in the table based on the temperature thermistor
readings.
Economy Mode
The Economy mode operates as follows:
Less energy consumed due to fewer pump cycles
Assumes plumbing is insulated (minimal pipe heat
loss)
Pump cycles on every 31 to 79 minutes (see
table).
Comfort Mode
The Comfort mode operates as follows:
Higher energy consumption due to more pump
cycles
Assumes plumbing is not insulated resulting in
higher pipe heat loss
Pump cycles on every 15 to 39 minutes (see
table).
Rinnai
Temperature
Setting
°F
Typical Pump ON Intervals*
(minutes)
Economy
Mode
Comfort
Mode
140
31
15
135
31
15
130
31
15
125
31
15
120
31
15
115
35
18
110
42
21
108
45
22
106
49
24
104
54
27
102
60
30
100
68
34
98
79
39
* The pump will cycle on at these calculated
intervals which are based on the temperature
setting, insulation, and estimated heat loss in the
system. The values for your installation may vary.
The optional MC195T-US controller provides a timer
function to control the on/off periods of the recircula-
tion pump.
