Paloma Water Heaters
PH2-25 (8.4 Series)  
Review and Buying Tips

Paloma PH2-25 tankless water heater

Check out how Paloma water heaters from the PH2-25 series are designed to use sophisticated features to optimize combustion and increase the unit's performance and safety.

Powerful Paloma tankless water heaters from the 8.4 series are recommended for homes with one to three bathrooms, as they can provide up to 8.4 gallons per minute of hot water. That means longer showers and baths, plus dishwashing, with endless hot water when you needed it.

Higher flow rates can be met in the southern warmer climates where the water heater can be used as the whole-house unit, while in the northern and colder regions, where the incoming water is cooler, Paloma PH2-25 is used in smaller homes or for point-of-use service.

Like other models from Paloma, PH2-25 is still energy efficient, with 30% or more energy savings than the tank-type units.

They are factory-built to use natural gas but can be bought or converted (by the certified installer) to use propane gas, with an energy efficiency of 84%, making them Energy Star compliant.


If you require professional assistance, contact your local water heater expert! Get FREE estimates here

Models review

Paloma PH2-25 series offers two types of tankless water heaters, an outdoor PH2-25ROFN and direct-vent or indoor model PH2-25RDVSN, with the 3"/5" concentric venting kit for safe exhaust and intake of the fresh air. The modulating gas valve allows them to work at the power range from 11,000 to 180,000 BTU and produce water flow from 0.44 to 8.4 gallons per minute.

The tankless units are excellent in providing hot water on demand and in continuous supply, but they are restricted by how much hot water they can provide. This is why Paloma recommends using the DUOnex system to connect two units in one and deliver even more hot water. When two Paloma units are combined into one DUOnex system, the first-hour delivery can reach high 480 gallons.


Endless and on-demand hot water.

  • 30% savings in energy when compared to tank-type heaters. The tankless design eliminates the standby heat loss, and the gas is used only when it heats the water.
  • Smaller than tank-type. Paloma tankless water heater is the wall-mounted unit, saving space and allowing flexible installation (bathroom, kitchen).
  • An outdoor model does not require any vent pipes, while an indoor can run either horizontally or vertically.
  • Advanced electronics provide accurate temperatures, better monitoring, enhanced efficiency and performance, diagnostics, and error display for easy troubleshooting.
  • An exclusive sensing burner and ICAD safety system (Incomplete Combustion Avoidance Device) on direct vent water heaters optimize the gas combustion and protect the household in a case of the increased amount of CO in the gas combustion chamber.
  • Plastic film wrap overheating limiter shuts down the water heater if there is an extremely high heat exchanger temperature.
  • Flame Failure Protection checks the firing and prevents flameouts by shutting the unit down.
  • A remote control with the easy-touch buttons for setting the temperature between 85 F and 140 F, and LCD display. Additional remotes are also available to buy, such as the Bath controller used to prevent scalding burns, especially in kids.
  • A commercial conversion kit allows temperatures up to 185 F.
  • The freeze protection system uses the electric heater and prevents freezing inside the water heater for the surrounding temperature of up to -30 F.

Similar tankless and condensing models:

Safety devices

  • ICAD - Incomplete Combustion Avoidance Device
  • Film wrap overheat limiter for fire protection
  • Anti-boil protector shuts down the water heater if there is not enough water flowing through the unit
  • Freeze protection system uses the electric heating elements


Paloma tankless water heaters from the PH2-25 series are mainly used for heating potable water but can be used as part of the circulating water system. It comes with a 12-year warranty on the heat exchanger and five on other elements. To have a valid warranty and use the unit for a long time, proper maintenance and preparation should be performed regularly.