Rinnai Circ-Logic RU98i User Manual

4 Rinnai Circ-Logic™ with Grundfos Kit
Rinnai Circ-Logic™ Descripon
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 seng, insulaon, and
esmated heat loss in the system. The
values for your installaon may vary.
How It Works
DIP switches (SW2 - white switches, #4, #8) should be set
correctly for recirculaon and mode. The Rinnai water heater
should be turned on.
Pump recirculaon 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
seng. If the inlet thermistor detects abnormal temperature
then diagnosc code 51 is generated and the pump will turn o.
When the return water temperature reaches approximately 15°
F (8.3°C) below the temperature seng, the water heater and
pump will turn o.
The cycle will start at the approximate me interval in the table.
The cycle stops based on the temperature thermistor readings.
The Logic has two modes of operaon: Comfort and Economy.
Economy Mode
Economy Mode uses longer me intervals (about twice as long
as Comfort Mode) and can be used for two purposes: to reduce
the energy consumpon required to keep the loop warm and/or
to maintain temperature in a loop that is well insulated.
Economy Mode operates as follows:
 Less energy consumed due to fewer pump cycles
 Pump cycles on every 31 to 79 minutes (see table)
 The me intervals are based on the assumpon that the
loop is insulated.
Comfort Mode
Comfort Mode has shorter me intervals and can be used to
either ensure the loop is always kept hot or to cope with a loop
that has a high degree of heat loss due to lack of insulaon, or
pipes that run through a concrete slab, etc. Comfort Mode
operates as follows:
 Higher energy consumpon due to more pump cycles
 Pump cycles on every 15 to 39 minutes (see table)
 The me intervals are based on the assumpon that the
loop IS NOT insulated.

Rinnai Circ-Logic RU98i Specifications

General

Category	Tankless Water Heater
Model	RU98i
Gas Type	Natural Gas or Propane
Energy Factor	0.95
Maximum Flow Rate	9.8 GPM
Minimum Flow Rate	0.26 GPM
Activation Flow Rate	0.4 GPM
Circ-Logic	Yes
Heat Exchanger	Stainless Steel
Maximum BTU Input	199, 000 BTU
Minimum BTU Input	15, 000 BTU/h
Temperature Range	98°F - 185°F
Vent Length	Up to 65 feet
Electrical Requirements	120V AC
Ignition System	Electronic
Warranty	12-year on heat exchanger, 5-year on parts, 1-year on labor