How to select the best John Wood tankless water heaters for home use. Condensing or standard type?
John Wood tankless heating appliances are designed for almost any home or light commercial application, from point-of-use service to the whole-house water heating. These small, compact and wall-hanging units are recommended for households that have high demand for hot water, with the larger families and homes that lack in space.
Even the largest model, with the size of approximately 22”x18”x11” and weight of 59 pounds, is easier to carry and install than the cylinder type. Non-condensing units are even lighter than condensing type.
The selection of John Wood tankless water heaters is so-so (not as found at Rinnai or Noritz manufacturer), and heaters are available as non-condensing from series 110, 310 and 510, and condensing type, series 240, 340 and 540, all built for indoor installation.
Non-condensing type of John Wood water heaters are coming from the JWT-110, JWT-310 and JWT-510 series; all utilize the conventional on-demand technology to provide continuous and endless supply of hot water.
The heaters can use either natural gas or propane, and provide the maximum energy factor of up to 0.83, which also meets the Energy Star requirements.
The main characteristics of non-condensing tankless units are one heat exchanger and the temperature remote controller that digitally displays the temperature and error codes.
The temperature remote controller TK-RE02 allows temperature adjustment from minimum 99F to maximum 167F or from 113F to 140F when changing the dipswitch position. JWT-510 is slightly different from other two models; it uses the TM-RE30 that allows temperature change from 99F to 185F and up to 4 units can be installed into one system when using the Easy-Link system.
The 510 water heaters have an option to use the recirculation pump, which helps in energy conservation. This is the only unit from this group recommended for commercial applications.
Those models that utilize the power vent design require vents from Category III and made of stainless steel. These gas appliances can also be converted to direct-vent type with the sealed combustion, and only when using the John Wood conversion kit.
John Wood tankless water heaters from 240H, 340H and 540H series come with the condensing technology that requires two heat exchangers, one that is made of commercial-grade copper (the primary unit) and secondary that is made of stainless steel and used to extract the latent heat from flue gases and preheat the incoming water. This is what provides the high energy factor of 0.95, which brings more savings to you and Energy Star compliance. The secondary HE must be made of high quality material as it deals with the flue gases which are in acidic condition and can corrode the element and shorten its lifetime.
State condensing and tankless water heaters are direct vent units and direct venting is what makes the installation easy and safe as the surrounding air is untouched. They can use the PVC, CPVC or PP venting with the Category IV stainless steel pipe.
At the front panel you will find the built-in temperature and error display for easy control and simple troubleshooting.
The system is fully modulating allowing the system to works in the power range from 11,000 to 199,000 Btu/hr and with the temperatures from minimum 100F to the maximum 185F. There are 9 settings available for 240H and 340H models, from 100F to 140F and 16 settings for 540H, or from 100F to 185F.
Only 540H unit can extend its power and be used in large homes with the high water flow, because it utilize the Easy-Link system that links up to 4 units or when using the multi-link it connects up to 20 units, but only with the controller. Whit the 20 units connected into one system, the system will produce up to 4.0 million BTU/h while still be able to modulate to its minimum power of 15,000 Btu/h.
Safety features include:
Air fuel ratio sensor (AFR)
Exhaust and water temperature sensors
Overheat Cutoff Fuse
Internal freeze protection
John Wood tankless water heaters from condensing category can be used in residential and commercial applications, for heating potable water and space heating (510, 240, 340 and 540 models). The warranty is long 15 years on heat exchanger in residential applications, 10 years in commercial, and 5 years on parts.
Picture is courtesy of John Wood company