Rinnai RX199iN vs RXP199iN (is the built-in recirculation pump worth it?)

The RXP199iN is the RX199iN with the recirculation pump moved inside the cabinet. Rinnai publishes the same input range of 15,000 to 199,000 BTU/h, the same UEF 0.98, the same 11.1 GPM (42 L/min) maximum domestic hot-water flow and the same 30.11 x 18.5 x 11.4 in envelope for both. The RXP adds the pump and about 3 lb of weight, 58 lb against 55 lb, and removes the need to buy and mount an external pump and pump cable for a return loop. That is the whole comparison, and it is the honest way to decide between them.

Recirculation itself needs explaining before the pump choice matters. It keeps hot water moving through a loop so the wait at a distant tap is shorter; it does not make hot water instant, and it adds gas use because the unit fires to keep the loop warm. The RX199iN achieves it with an external pump and Rinnai's controls, using either a dedicated return line or a crossover valve. The RXP199iN has that pump integrated, so the loop is simpler to install and there is no separate pump to mount, wire or service, but the pump is now part of the heater and its service is tied to the unit.

The flow figure is a manufacturer rating with no stated temperature rise on either model, so 11.1 GPM is not winter delivery and the two are not distinguished by it. In Metro Vancouver, incoming water in winter can sit below 8 °C, so heating to a 49 °C shower is roughly a 40 °C rise, and the deliverable flow at that rise comes from the flow table in manual 100000839. Both models share the 0.4 GPM minimum activation flow, the 3/4 in gas connection, the 1/2 in NPT condensate drain, PVC/CPVC/polypropylene venting, 120 V power and SCAQMD ultra-low-NOx approval.

The decision is therefore about the loop, not the heater. If the home has, or will have, a recirculation return line and the owner wants one appliance to handle it, the RXP199iN is the cleaner answer. If the home will not recirculate, or the installer prefers a serviceable external pump, the RX199iN is the same heater for less complexity. Rinnai's published residential warranty applies to the platform, 15 years on the heat exchanger with 5-year parts and labour when registered within 90 days. Whether CANRO supplies a given model and performs a gas tank-to-tankless conversion is confirmed at consultation.