The step up from domestic water heating to commercial projects is a big one. Commercial water heating is a different ballgame with a new set of rules for design, installation and maintenance. 
   Success in this field often depends on the knowledge and training of the plumber or contractor and the ability to work with diverse clientele. 
   For commercial work, it's important to be forthright with customers and manage their expectations appropriately, said Jason Fleming, national sales manager for Noritz in Fountain Valley, Calif. "Plumbers should make sure to educate the customers on what the true advantages of their system are. It is important to explain how much energy they can expect to save over their current system, the maintenance required on their product, and what sort of service they provide in the case that a problem arises. 
   Joining Fleming this month on our panel of industry experts are Ron Johnson, product manager for Rheem, Rod Hyatt, national solar products manager for HT Products, Matt Schultz, senior manager for commercial products for A.O. Smith, and Stan Young, a spokesman or Raypak. 
   Every application-hotel, laundry, restaurant-has unique requirements, said Rheem's Ron Johnson. "Understanding the application in terms of anticipated hot water volume and delivery temperature is critical. One question the installer should always ask the business owner is 'Did the previous unit provide enough hot water?' This will give the installer a starting point for determining the correct water heater size in a retrofit situation. 
   "Rheem Certispec application sizing software is a free download on our website. It helps plumbers choose the right commercial models for even the most complex applications. If the plumber needs additional assistance, we have a team of experts that will help them with the selection. Installing the right water heaters will ensure the best possible system performance and product life for the customer." 
   Plumbers often are not up-to-date on new products or requirements that would better fit in a commercial application, said Rod Hyatt, national solar products manager, HT Products in East Freetown, Mass. "For example, for the new gas water heaters, the venting has different rules; we have to deal with condensates that are continually draining, and some new water heaters need to have the gas-fuel mixture checked with a gas analyzer." 
   "It's increasingly important that plumbing contractors gain a full understanding of the entire installation to ensure proper operation and maximize the useful life of the commercial water heater," Schultz said. "Water quality, tank temperature set point, properly sized expansion tank and water pressure are some of the main factors that can impact tank life." 
   Maintenance costs and 24/7 availability of hot water are always important to commercial owners, Raypak's Young said. "Knowing water hardness at that specific site for system design is as important as the equipment selection for the contractor to meet these two key and ongoing requirements." 
   The key issue plumbers and mechanical contractors will find different with commercial customers is a much wider spectrum of owner preferences and job site requirements, Young added. 
   "Each installation will itself differ, often dramatically," he said. "Owners and spec builders may simply desire the lowest first cost, regardless of total life-cycle costs or actual operating efficiencies. The equipment selection criteria of other owners or engineers may be to satisfy the very general minimum requirements for LEEDS points, utility rebates, or federal/state/local government regulatory requirements." 
   Young noted that intelligent long-term investors and owners will seek the advice of experienced engineers and design-capable contractors to select a truly cost-effective, long-term solution for system design and equipment selection, in order to minimize first cost and optimize total seasonal efficiency; that is, the best payback. "All commercial installations must consider recently more strict safety codes, like ASME, CSA and low lead certification, to both meet state and local regulations and avoid future liability issues." 
   Water heating systems for commercial buildings should be designed by an experienced DHW engineer or design/build contractor, then started up and maintained by factory trained technicians, Young said. "Commercial systems need to be properly tuned in, multiple DHW boilers or water heaters flow balanced, and thoroughly safety checked during start up. Maintenance and inspection should be preventative, periodic, and per the manufacturers instructions to avoid down time."

RJ: What are the typical installation and/or maintenance issues with specific categories: gas and electric tank, hybrids, tankless, solar?

Gas Water Heaters:

Rheem: Most problems with gas water heater installations fall in two areas: Gas inlet sizing and venting. Either the gas pipe coming into the heaters is undersized or the venting is not installed correctly. Following state and local codes and the use and care manual will eliminate most of these issues

HT Products: Old-style gas heater. Standard installation and usually metal venting. These are the least efficient of any water heater because of the tank's heat loss, which is primarily because of the vent pipe that runs up the center of the tank. Most old-style burners are 60-70 percent efficient when they are new. But when the tank is losing heat all day long, the burner must burn fuel to replace that lost heat, resulting in even lower efficiencies. 
   New-style high efficiency condensing gas water heater: Annual checkups but generally little maintenance. Low tank heat loss. Standard installation except the venting. These water heaters generally need electricity to run the burner and fan. For new construction this will be easy; for a replacement water heater, it may get more complicated dealing with the additional fresh air return (if needed) and different venting material. These water heaters will also need a condensate drain.

Noritz: The main issue associated with the installation of a gas water heater is the physical size of the units. Often weighing multiple hundreds of pounds, moving and installing the unit can be difficult. In commercial applications, water heaters are often located in suboptimal locations for installation (i.e. basements, rooftops, attics), where the transport becomes a significant issue. In California and other seismic regions, tanks also often require special construction to account for potential seismic issues.

Raypak: The propensity of both gas and electric tank-type heaters to scale and/or corrode depending on the water conditions at a given location is well known. This is multiplied when several units are ganged up in a commercial building to meet the load. This scaling potential can also be accelerated by the improper system balancing that often occurs with more than two or three units piped together. 
   Direct-fired high-recovery high flow velocity copper finned single or multiple tube boilers, in single or 2-4 multiple boiler systems are the ones most often selected for the medium and larger commercial installations. Copper fin tube boilers offer higher efficiency ratings than standard tank type, and operate scale free by design in most installations without the need for a softener. 
   If the newer condensing models are selected, both copper fin and tank type heaters can all achieve steady state efficiencies in the high nineties with very low return water temperatures. However, when standby losses and maintenance costs are added to the equation, the total pay back available from high recovery low water volume copper fin boilers still win for total energy savings. They can most effectively avoid standby and vent losses.

Electric Water Heaters:

Rheem: Typical installations issues with electric water heaters are incorrect wiring or units that are undersized for the application. Another common issue is a breaker that's too small. The unit will trip the breaker repeatedly and a larger replacement breaker must be installed for proper operation. Always refer to the use and care manual for specific information.

HT Products: Electric water heaters: Little maintenance. Standard installation. No vent. Low tank heat loss. They are usually the most expensive to operate (depending on location) and generally need higher voltage unless it's a small, single-use under-sink water heater. Because conventional electric water heaters require higher voltage, they must be hard-wired to a dedicated circuit breaker, according to local codes or latest addition of the NEC ANSI/NFPA 70. Electric water heaters are the slowest to recover and produce less hot water per hour than a gas water heater of like size.

Noritz: Similar issues with regards to size as gas type tank water heaters, but will also had electrical supply considerations as well. Electric tanks require extremely large electrical services (240 VAC or higher). This often necessitates special wiring considerations not seen with other types of technology.

Tankless Heaters:

Noritz: Tankless units trade physical size with quantity. A typical commercial installation requires more than one unit. This will necessitate multiple vent terminations in most cases, which require large amounts of side wall or roof space. Another consideration with tankless type installations is the higher instantaneous gas draw when compared with a comparable tank type installation. Gas line sizing is critically important, and can be a difficulty in retrofit applications.

HT Products: These units deliver hot water without storage; this can be advantageous in tight spaces. Tankless water heaters also eliminate tank heat losses. Tankless water heaters take a different approach: Unlike a tank-style water heater that delivers its full volume as fast as you can draw it out, a tankless has no volume and can only deliver the smaller amount of GPM that it is rated for. However, it can deliver this smaller GPM indefinitely. 
   Customers may be unhappy to find they can't take a shower at the same time they're running the dishwasher or washing machine. Higher flow tankless water heaters are getting to be more available. However, firing a large tankless water heater to wash your hands is kind of like revving up the gas in your car and then slamming on the brake - they both use a lot of fuel to do it. Tankless water heaters generally have the highest maintenance of any water heater and they don't tolerate hard water.

Raypak: Tankless heaters have recently been widely promoted for commercial jobs. A whole row or more of small units are piped together. They operate on demand, turn off when not needed and so can avoid nearly all standby losses. When more than two or three are utilized, both tank and tankless units face the same installation complexity, flow balance, and frequency of repair issues. Waterway cleaning, a challenging task, is the recommended maintenance solution.

Hybrids:

Noritz: Most similar in installation to tankless water heaters. They are typically high BTU appliances with low amounts of storage. Physically, require very little space for install, but require additional venting and gas line consideration.

HT Products: These usually are a heat pump with an electric element to back up the heat pump when it can't do all the water heating. Because they have electric backup, higher 240 voltage is needed and must be hard-wired directly to a circuit breaker or according to local codes or latest addition of the NEC ANSI/NFPA 70. Heat pumps also need a condensate drain.

Solar heaters:

Noritz: By far the most complex type of installation, solar installation requires significant roof space for installation along with extensive wiring of controls. For commercial installations, a supplementary and/or backup water heating source is often required as well. Due to the fluctuating nature of solar energy gains, additional 100 percent backup is often required, which will add additional complexity to the installation (bypass piping, switching valves/shutoffs).

Raypak: We all welcome the fossil fuel-saving benefits that solar, geothermal and other supplemental alternative energy sources offer, so compatibility with them should be included in all commercial DHW system designs. If the desire is to go green, be awarded LEED points and recognition, or receive rebates, if you can overcome the acknowledged longer payback associated with these emerging technologies in the owners views they should be made part of the initial system specification. 
   Compatible system design should not only mean with solar, but geothermal, heat recovery and other sources that may exist, or become feasible later. While solar adds a little more complexity, any scaling issues can usually be mitigated by proper flow velocity and/or waterway material selection, keeping maintenance to a minimum.

RJ: What kind of support can contractors and installers need in working with these systems and what assistance do water heater manufacturers provide?

Noritz: The number one area of support that contractors need is knowledge. Knowing how to install the system properly is the number one way of avoiding problems in the first place. Noritz offers a full series on commercial water heating trainings, starting from the advantages of a Noritz commercial water heating system, to installation, to system design, and also on servicing and repairing an installed system. 
   By arming the contractor with all the tools beforehand, we hope to prevent most issues from blowing up before they happen. Additionally, Noritz systems are designed with digital readouts that communicate errors and partial system functionality to further avoid downtime. 
   Should downtime occur, we offer class leading technical support, as well as a support website that includes documentation on troubleshooting a Noritz water heating system. This includes error code and diagnostic data, step-by-step system disassembly/reassembly instructions, plumbing diagrams, and installation manuals.

HT Products: For the higher performance, more efficient appliances, it's very important for contractors and installers to get trained and educated because of the different installation requirements and codes that address them. It's a lot like the older atmospheric boilers vs. the new condensing modulating models - they're comparable technology upgrades.

Rheem: Rheem provides support to installers three ways: Sizing software (Certispec) is available as a free download from our website in the Commercial Products sections. Online Use & Care manuals are also available; technical support is available at 1-800-HEATER3; and Rheem Water Heater Institute provides classroom training, which is offered onsite or at our headquarters in Montgomery, Ala.

A.O. Smith: With the rapidly changing commercial water heater market and new products being introduced, it is important that contractors reach out to their local manufactures representative for the latest information.

Raypak: "Technical training for installation, start up, and maintenance personnel is vital to all successful installations." Young said. "A shortage of the type of skilled individual suitably trained to do these tasks has developed everywhere. For many years Raypak has emphasized and currently offers both factory and local training schools for our DHW systems, equipment and controls. We make available Webinars and CD's, plus we employ a full- time training director. 
   "We also maintain at the factory several experienced applications and service support personnel for field inquiries. But, the real "go to" source is our cadre of over 60 independent, factory-trained salesmen and manufacturers rep organizations. They are trained system engineer/designers, standing behind what they and we sell."