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Rinnai RUC98iP Ultra Series Review


Unlike other similar tankless water heater of this class, this Rinnai heater uses propane instead of natural gas. You can use both concentric and PVC venting with this unit. This item will match well any pieces of appliance that you have in silver or metallic finish.

Like the other Rinnai heaters, this one is also highly efficient as it is characterized by a maximum BTU – 199 000 and 0, 96 energy factor. Surely, this is the reason because of which the heater is Energy Star certified. The fact that this unit is efficient doesn’t mean that the flow rate will be decreased. To be more exact, we can say that it has a flow rate of 9, 8 GPM.

Thanks to the fact that this heater produces little to no NOx emissions, we can also consider it an eco-friendly option that won’t harm the environment.

What Does It Do?

Rinnai RUC98iP Ultra Series Propane Tankless Water HeaterThe fact that this heater is a condensing one leads to its high efficiency.  Remember to connect the condensate drain to the outside as there may be a lot of condensation occurring while the system is in operation. As we have mentioned above, this unit offers two types of venting. If you use PVC venting, then you need two pipes. Respectively if you use concentric venting, then you need only one pipe. Keep in mind that this unit can be installed only inside. In case you want to use this heater with well water, you can do it, but you need to have a good water softener as this system doesn’t work properly with hard water.

The Content of the Package

  • A propane tankless water heater
  • An MC-91-2US controller
  • A remote
  • Isolation valves

Please, note that the exhaust pipe parts must be purchased separately.


Voltage: 120 volts

Item Weight: 82 pounds

Product dimensions: 10 x 18,5 x 26 inches

Size: large

Colour: silver

Flow Rate: 9,8 GPM

Warranty: Limited 12-year on heat exchanger, 5-year on parts, 1-year on labor

Commercial: Limited 5-year on heat exchanger, 5-year on parts, 1-year on labor

What to Expect?

The first thing you need to know about this unit is that you can install it everywhere because it has a very compact design. One can easily mount this heater as it comes with very detailed and clear instructions. However, it is advisable to ask a professional to do it as it needs to be vented and plumbed properly.

Don’t worry if the unit or any of its parts get damaged as Rinnai offers a 12-year warranty on the heat exchanger, a 5-year warranty on the elements, and 1 to 5 years – on labor. Just remember that if you want to benefit from the warranty, you need to have your heater installed by an expert, and after that, you need to register it online. If the power goes out, then you cannot use the heater as it still needs electricity.


  • Rinnai offers two types of venting for this heater – a concentric one and a PVC one. In the first case, you need only one pipe, in the second one-two pipes.
  • Whenever the unit or its parts get damaged, you can take advantage of the long warranty period – 12 years for the heat exchanger, five years – for the elements, and 1 to 5 years for labor.
  • This heater is a highly efficient one, and it has 199, 00 BTU, and a 0, 96 energy factor.
  • Considering the fact that this system produces almost no NOx emissions, we can conclude that it is an eco-friendly product.


  • It may take around a minute for the hot water to come to the tap, especially if the heater is situated far away from it.

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