Paloma PH2-28 Water Heaters from the 9.5 Series

Paloma PH2-28 tankless water heater

A review of the Paloma tankless water heaters from the 9.5 (PH2-28) series for use in large homes with high hot water demand. Explore Paloma PH2-25 top features and see how these tankless units can save you money and time.

Models review

As found among other Paloma tankless water heaters, the 9.5 series comes in two models; indoor and outdoor, using both natural and propane gas for heating potable water:

  • PH2-28RDVSN - indoor direct vent model, powered by natural gas
  • PH2-28ROFN - outdoor mode,l powered by natural gas
  • PH2-28RDVSP - indoor direct vent model, powered by propane gas
  • PH2-28ROFP - outdoor model, powered by propane gas

Paloma 9.5 units are the manufacturer's largest non-condensing tankless water heaters and have the highest water flow and gas input rate. The heaters can also be used in commercial applications as long as the conversion (installation of the commercial chip) is done per the manufacturer's instructions.

Features and benefits

Power and efficiency

All Paloma 9.5 tankless water heaters are designed with the modulating gas valve, which allows them to work in the range from the minimum power of 11,000 BTU to the maximum power of 199,900 BTU. When working with the full capacity, they can provide high water flow rates of 9.5 GPM that ensures comfortable multiple-shower use and high thermal efficiency of 84 %, providing decent savings either using propane or natural gas.

The energy-saving modulation won't be that efficient if there is no help from the advanced microprocessor, which controls many parameters during the water heating operation.

Adjusting temperature and remote control

The operating temperature is factory set between 100 F and 120 F while the temperatures from 85 F to 140 F can be achieved and regulated on the Main remote control (UMC-117), which is supplied with the unit.

The remote controller is very simple; it allows you to adjust and monitor the temperature in Fahrenheit (F), while the LED screen displays the water temperature, and if there is a problem, an error code.

Capacity and flow rate

Because of its high-volume capacity, Paloma 9.5 models are the whole-house water heaters, able to provide enough hot water for up to three simultaneous showers in colder regions (flow rate is 5.2 GPM when the incoming water temperature is 60 F) and even more in warmer areas (the maximum flow rate is 9.5 GPM).

If there is a demand for more hot water, the DUOnex system can be used, which allows a connection of the two units into one system. Such a system, ensures high first hour ratings of up to 525 gallons.


Paloma 9.5 water heater PH2-28RDVSN is an indoor and direct vent model that utilizes the 3" x 5" stainless steel concentric venting and an electric blower for safe removal of the exhaust gases out, either horizontally through the wall or vertically through the roof.

The PH2-28ROFN model is the outdoor model that does not require any venting (it uses the flue terminal), and it must not be installed indoors or in an enclosure. The remote controller is also supplied with the outdoor models but must not be installed outdoors.


Like other Paloma models, Paloma 9.5 tankless water heaters are equipped with the exclusive sensing burner and ICAD safety system that optimize the combustion and protect the user if there is an increased level of carbon monoxide (CO).

And, if the water heater fails to heat the water, the self-diagnostic program will register it, and the error code will display on the LED screen of the remote control.

These units are very safe as they are designed with several features, which protect against scalding, carbon monoxide leak, fire (thanks to the Overheat Limiter Wrap), anti-boil, and freezing. The freeze protection system uses the electric heater to prevent freezing inside the water heater, only if the temperature does not drop below 30 F.


Models/Features PH2-28RDVSN PH2-28ROFN
Gas input (BTU) 11,000
Water flow (GPM) 0.4-9.5 0.4-9.5
Energy Factor 0.82 0.82
Temp. settings (F) 98-140 (185) 98-140 (185)
Vent size (ft) 3"/5" - 36 N/A
Altitude height (ft) 3280 3280
Size (inch) 13 7/8 x 25 5/8 x 9 7/8 13 7/8 x 23 5/8 x 8 7/8
Weight (lbs) 55 55

Feature highlights

  • Energy-saving design.
  • Low NOx compliant.
  • ICAD system to optimize gas combustion and protect from carbon monoxide poisoning.
  • Compact and space-saving - wall mount.
  • DUOnex-ready to connect two units.
  • Electronic manifold ready to connect up to 20 units.
  • Can be installed as part of the circulating system.
  • Self-diagnostic and error system.
  • Standard gas and water connections of 3/4".
  • Protected using the flame rod, anti-boil, anti-scald, overheating and anti-freeze systems.
  • Can be used in commercial applications.
  • Warranty; 12 years on the heat exchanger and 5 years on other parts.
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