John Wood Tankless Review

Consider the following facts and tips when selecting the best John Wood tankless water heaters for on demand heating of potable water in residential and light commercial applications. The article reviews the top features and benefits of the combined on demand and condensing technology.

Top Features and Benefits

High efficiency

John Wood Tankless

All the John Wood water heaters designed for on-demand water heating are using Takagi technology. Models that utilize the condensing technology are ultra-efficient models that come with two heat exchangers; one made of commercial grade copper and second made of the stainless steel, making the units resistant to the aggressive water action. 

Such a combination allows the usage of the latent heat from the flue gases for the high thermal efficiency of over 90%. Non-condensing series consist of the conventional models that are able to provide an energy factor of 0.82 and 0.83.

Flexible venting

With the higher thermal efficiency, especially those models with the energy factor in the range from 0.91 to 0.95, water heating costs are significantly reduced. Also, the products of combustion have the lower temperature, which allows venting with the approved PVC, CPVC and PP pipes, for added flexibility and lower costs. The venting system is flexible as it can be installed as the two-pipe system or coaxial direct vent, horizontally or vertically.

Fast delivery

For homes where the higher demand is needed with the stable temperature and fast delivery, .... you can use the FlowTHRU storage tank that is specifically designed to work with John Wood tankless water heaters for added comfort. For the supplemental heating, FlowTHRU storage tanks are equipped with one electric heating element, an adjustable thermostat and side connection to a circulation pump.

Advanced electronics

The condensing water heaters feature the advance electronics that provide easy temperature adjustment right on the built-in screen, diagnostics and features that help prevent scalding burns, also the advanced safety features such as the internal freeze protection system.

All the condensing units are using the advanced features such as the self-diagnostic system for safety and your convenience. The integrated controller allows you not only to change and monitor the temperature of hot water, but check other parameters and also error codes if the problem exist. On non-condensing units, the error code will show up on the remote controller and computer board.

emergency plumber

  • Warranty - 12 years.

  • Direct venting with the sealed combustion for indoor models available.

  • Maximum exhaust vent piping length is up to 100 ft.

  • Convenient automatic ignition.
  • Safety: thermistor and hi-limit switch for the exhaust gas, freeze protection...

  • Some models use Easy-link up to 4 units without multi-unit controller (510 and 540 H models only).

  • Multi-Link connects up to 20 units into one system, so the power can modulate from 13,000 to 4.0 million Btu/hr.
  • 240, 340 and 540 series are condensing models.

  • Ultra Low NOx models are available.
  • Recirculation pump control mode available on 510 water heaters.

  • Temperature adjustment from 100 to 140 F, or 100 to 185 on 540 H models.

Model selection

Specifications - Technical Data

Min/ Max
# of
Remote /
JWT-240H-N 15,000
0.95 6.6 99
2 Yes
JWT-320H-N 13,000
0.91 8.0 99
3 Yes
JWT-340H-N 15,000
0.95 8.0 99
3 Yes
JWT-520H-N 10,300
0.91 9.0 99
4 Yes
JWT-540H-N 15,200
0.96 10.0 99
4 Yes
JWT-110-N 19,500
0.82 6.0 99
2 Yes
JWT-310-N 11,000
0.82 8.0 99
3 Yes
JWT-510-N 11,000
0.82 10.0 99
4 Yes

Related articles

(The pictures are courtesy of John Wood website)