Tankless Propane Water Heater 4.22 GPM CX422 - Compact Indoor Unit

Our review of the CAMPLUX CX422 tankless propane water heater finds it best suited to compact homes and mobile living where steady on-demand hot water for one to two fixtures matters most. The single biggest reason to consider this unit is its balance of flow and control: a rated 4.22 GPM output combined with a sensitive digital display and smart flow sensors makes it straightforward to get consistent hot water without a large footprint. This review focuses on real-world strengths and known limitations so you can decide if it suits your setup.

Key Features

• 4.22 GPM output: Delivers continuous hot water suitable for two to three light water points, making it a strong pick for small houses and apartments.
• Precise temperature control: The IMD digital display and smart chip hold output within about 1F, so users can dial in a comfortable shower temperature easily.
• Anti-freeze protection: Four 100W heating modules engage at low ambient temps to prevent the heat exchanger from freezing when the unit is left powered.
• Compact design: The indoor CX422 saves significant floor and wall space versus a tank heater and fits standard 3" venting for easy placement.
• Energy efficient heat exchanger: A copper heat exchanger and four heat modes improve transfer and offer seasonal energy savings options.
• Standard connections: Uses 1/2" NPT gas and 3/4" NPT water connections and a UL-approved plug for simpler installation with common fittings.

Who It's For

The CX422 is aimed at owners of compact homes, mobile homes or small apartments who need a space-saving propane tankless water heater that provides steady hot water for a shower plus a second fixture. It suits buyers who value precise digital temperature control and who can provide compatible venting and a pressure relief valve kit.

People who should look elsewhere include households needing high simultaneous flow for multiple full bathrooms or users who cannot meet indoor venting and gas pressure requirements. Also, if you require guaranteed 40F temperature rises under all conditions, some customer reports indicate that performance can vary with inlet temperature and gas supply.

Pros & Cons

Pros

• Compact footprint and standard venting make installation in tight spaces practical.
• Clear IMD digital display and fine temperature adjustment improve user control.
• Anti-freeze feature and multiple heating modes increase reliability in cooler climates.
• Copper heat exchanger offers good thermal transfer and corrosion resistance.

Cons

• Some users report inconsistent heat rise and ignition or shutoff issues, so performance may depend on gas pressure and setup.
• Vent pipe and valve kit are not included, adding to installation steps and cost.

Specifications

Rated Flow	4.22 GPM
Rated Heat Output	102,000 BTU/hr
Temperature Range	95F-149F
Gas Type	Liquid Propane
Electrical	120V/60Hz
Water Connections	Cold 3/4" NPT / Hot 3/4" NPT
Gas Inlet	1/2" NPT

Our Verdict

The CAMPLUX CX422 is a solid value for small homes and mobile dwellings that need an efficient, space-saving propane tankless water heater with precise digital control. It blends good flow, a copper heat exchanger and freeze protection into a compact indoor unit, but buyers should plan for proper venting, a pressure relief valve kit and verify gas supply to avoid ignition or temperature issues.

Frequently Asked Questions

Does the unit require special venting?
The CX422 uses a 3" flue pipe and fits standard stainless steel vent kits; a separate vent kit and wall thimble are optional and not included.

What connections are required for installation?
The heater uses a 1/2" NPT gas inlet and 3/4" NPT water inlets/outlets; a valve kit with a 110 PSI relief valve is recommended but not included.

Will it work in freezing temperatures?
It has anti-freeze protection that activates around 39F when the unit is continuously powered, but exterior conditions and water supply should still be considered.