Rinnai Circ-Logic Installation And Operation Manual page 3

Thank you for purchasing a Grundfos GTK03U Kit. Before installing and operating this pump, be sure to
read these instructions completely and carefully to familiarize yourself with the pump's features and
functionality.
Rinnai's recirculation technology is called Circ-Logic. Circ-Logic allows consumers to set recirculation
patterns that coincide with their hot water usage patterns. Hot water is available when needed, without
circulating it during times of inactivity. The GTK03U kit, manufactured by Grundfos, allows the user to
enjoy Circ-Logic with VC, KB, and SENSEI™ series tankless water heaters on a dedicated return line
with the use of an external pump.
For all models, Circ-Logic operates in either Comfort or Economy Mode (the modes are selected by dip
switches/parameter settings inside the water heater):
•
Comfort mode—Cycles the pump more frequently, ensuring the loop temperature remains
higher (but also uses more energy).
•
Economy mode—Cycles the pump less often, using less energy to maintain the circulation
loop temperature.
This manual contains the following sections and appendix:
•
Section 1 describes the contents of the GTK03U Kit and pump installation guidelines for all
tankless water heater models.
•
Section 2 contains installation instructions for SENSEI™ tankless water heaters. If you are
installing a GTK03U Kit on one of the following tankless water heater models, follow the
instructions in Section 2.
•
RU199i/e
•
RU180i/e
•
RU160i/e
•
Section 3 contains installation instructions for non-SENSEI™ tankless water heaters. If you are
installing a GTK03U Kit on one of the following models, follow the instructions in Section 3.
•
RLX94i
•
RL75i/e (VC models)
•
RL94i/e (VC models)
•
RU98i/RUC98i and RU98e (KB models)
•
RU80i/RUC80i and RU80e (KB models)
•
Section 4 provides information on operating the GTK03U pump and troubleshooting for all
models.
•
Section 5 is an appendix containing system drawings for recirculation with a GTK03U Kit pump.
•
The pump must be installed in accordance with these installation instructions when Circ-Logic
is used.
•
This document is intended to be used as a guide only and not as a replacement for a
professionally engineered project. The contractor/engineer must determine the necessary
components and configuration of the particular system being installed. This document does not
imply compliance with local or national building codes. It is the responsibility of the engineer or
contractor to ensure the installation is in accordance with all local building codes. The water
heater and plumbing system should be installed in accordance with local codes and the Rinnai
Tankless Water Heater Installation and Operation Manual.
Rinnai Circ-Logic with Grundfos GTK03 Kit
•
RU130i/e
•
CU199i/e
•
CU160i/e
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