Patterson-Kelley Solutions Blog

Direct Fired Water Heating Solutions

[fa icon="calendar"] Aug 21, 2018 11:10:46 AM / by Patterson-Kelley


Hot Water in an Instant

shower head steamWhether you take long, hot showers in the morning or use large amounts of hot water at your workplace, the need for a water heating system that is consistent and reliable is crucial. Water heating technology has made amazing breakthroughs, and today manufacturers can offer water heating solutions for a variety of needs.

Smart and highly efficient condensing equipment has become the top trend in the commercial heating industry. Building owners want hot water, and they want it in an instant and at low cost.

How can the industry accommodate these needs?

Instantaneous condensing water heaters have become a hot commodity in commercial and industrial environments.  In the commercial/industrial setting, the needs of an on-demand product, like the ones seen in the residential market, are highly sought after.  Needs, such as these may require additional storage and/or additional units to meet the varying demands of the facility, thereby labeling instantaneous condensing water heaters as cumbersome.  An appliance that has a small volume of storage is ideal because it allows time for the larger water heating equipment to fire to the needs of the system. Additionally , the tank on the appliance would need to be thoroughly blended for accurate readings of the unit’s outlet water temperature.

A unit that can maximize its turndown capabilities would also be ideal.  No two domestic systems will operate identically all the time. This would require  a commercial unit to capitalize on its range of heating capabilities to prevent the unit from over firing or short-cycling.  As discussed in the turndown post, maximum efficiency and system efficiency mandate certain restrictions. In the domestic water sector of the industry, the governing boards limit the turndown capabilities of the domestic condensing water heaters to 5:1.  The closest a water heater can get to reaching that capability, the better range the equipment has to meet the building demand precisely.

Patterson-Kelley’s Alignment with the Industry’s Needs

HiDRA-1Hot off the production line from Patterson-Kelley is the HiDRA™ Instantaneous Condensing Water Heater.  This is P-K’s first water heater only product launched into the condensing domestic market.

The equipment offers a 5:1 turndown ratio, the highest certified turndown capacity for domestic water appliances, as stated above. The specified turndown ratio maximizes the efficiency and effectiveness of the condensing water heating unit.

The tank itself can store 128 gallons of domestic water for on-demand hot water needs in any building.  Thanks to efficiencies up to 97%, recovery rates range beyond 2,000 gallons per hour.

Tapping into the wisdom of other P-K products, the HiDRA has a dedicated tank recirculation line with the intention of thoroughly mixing the domestic water inside the vessel.  An added benefit of the recirculation is anticipated temperature control. The temperature sensor in the recirculation line provides faster response from the unit by forcing changing temperatures and flow demands from the facility.

HiDRA Connection Location


The HiDRA comes standard with a 15-year warranty on the heat exchanger and is readily available in 800-1000 MBTU models.  Meeting standards as set by the ASHRAE 90.1 and NSF compliance, the HiDRA meets the needs of most facilities including hospitals, schools/universities, offices, and multi-family living environments.


If you would like to know more about the design of the HiDRA, please contact


 Join Patterson-Kelley at the ASPE Convention & Expo Booth #1555.


Topics: Water Heaters, Direct-fired, Condensing, Instantaneous


Written by Patterson-Kelley

Located in East Stroudsburg, Pennsylvania, Patterson-Kelley is a recognized market leader and major producer of heat transfer equipment. Our hydronic boilers and water heaters are installed in institutional, commercial, and industrial building applications such as schools, offices, apartment buildings, dormitories, hospitals, and hotels.