Installation Manual
Rinnai Tankless Rack System (TRS) Installation Manual     47 
IMPORTANT:  This secon is only for TRW02ST and TRW03ST rack models 
ulizing a dedicated recirculaon return line in the plumbing system. 
All TRW02ST and TRW03ST racks are shipped congured for a dedicated 
recirculaon return line. A single return line will connect to the RUR199 unit 
below the cold isolaon valve as shown in the below schemac. Using an 
EZConnect cable, connect the primary unit (RUR199) to a secondary unit 
(RU199).  
For the TRW03ST model with mulple RU199 units, the second RU199 must 
ulize a Pressure Acvated Valve.  
Dedicated return line connecon 
3/4” FNPT  
Unscrew the square head threaded plug 
to connect the building dedicated 
recirculaon return line. 
WARNING: Make sure the water supply is 
o and the system is depressurized.  
RUR199 
(Primary) 
RU199 
(Secondary) 
RU199 
Units Connected with  
EZConnect Cable 
Installed with a 
Pressure  
Activated Valve 
Congure TRW02ST and TRW03ST Racks for  
Dedicated Mode (Dedicated Recirculaon  
Return Line) 










