We want people to service their water heaters and we want it to be a bargain. In this arena, time literally is money, since the cost of service is directly related to how long it takes to perform the service. We have some ideas on how to cut down on both, depending on which kind of commercial water heater you have. They tend to come in two flavors, light and heavy. We're going to break it down by those two categories, give you our ideas in a nutshell and then explain the why behind the what. So....

Light commercial gas and all types of electric

We define this as Btu in the range of perhaps 75,000 to 125,000, typically one flue, often one anode; two at most. Gallonage is typically 75 to 100. Wattage is 9,000 and up.

The nutshell

• Top-plumbed with stainless steel or copper flex lines
on gas-fired tanks

• Earthquake-strapped with heavy bands lagged to wall studs, if the tank is in a seismic zone


• Hot as well as cold shutoff valves if it serves a multi-story building


• Ball valves used as shutoffs


• Temperature/pressure relief valve (T&P) installed so that it can be easily disconnected from the water heater and drain line and replaced


• Recirculation pump (if there is one) valved for flushing


• Vent pipe sections fastened with sheetmetal screws, NOT tape


• Thermostat set at 130 degrees (if the thermostat just says "warm, hot, very hot," test at tap with a meat or candy thermometer and adjust accordingly


• Maximum insulation available

The why behind the what

We prefer top-plumbed in this case because often there is just one anode in these types of heaters and we need at least two ports through which to vacuum. Flex lines ensure that the plumbing can be swiftly and easily disconnected and reconnected. Unions rarely come apart and often won't go back together afterward. For electrics, it's less important because the plumbing won't be disconnected to clean sediment. That will be done through the cleanout hatch.

In California, the straps have been code since 1992 for new and replacement tanks. But often, we've either seen no straps or flimsy ones of plumber's tape screwed into the plasterboard. Blocking behind a tank is not code, but we think it's a good idea if there's enough room for a tank to rock.

If a tank is on a lower floor of a multi-story building, and there is no hot shut-off valve, then when it is opened, all the water in the upper piping is going to run out there, complicating service and making it take longer. That makes it more expensive. Ball valves are not infallible, but they are generally more reliable than gate valves.

The treatment of the T&P is based on our belief that it should be regularly tested and replaced if it doesn't work properly. That's easier if it can be easily disconnected from the drain line and unscrewed.

We've created a recirc page with a diagram and photographic examples to illustrate our thinking on this, but it's important to flush air from the system after a tank has been opened. Our configuration facilitates that.

We've run across about 20 fallen vents and countless others that were in danger of falling. Sometimes it was because someone had merely shoved the sections together, others because they had been taped together and the tape failed. If three screws per section are used, it's much less likely that a vent can fall down or even be knocked down.

A thermostat setting of 130 is a tradeoff temperature. Legionella bacteria that cause Legionnaire's disease have been found growing in tanks set at 120. The bacteria can be inhaled as mist during a shower. Much above 130 and there is considerable risk of scalding and related injuries, such as falls.

You'd think the insulation issue would be a no-brainer, but we've found where apartment people who didn't know better let a plumber replace a light commercial water heater with a tank of only R-6 insulation, when it could be R-24. Management pays the gas bills for this type of heater and it's very much in your interest to get the most insulation possible.

High-recovery gas

We define this as Btu over 125,000, multi-flue, three to five anodes. Gallonage doesn't really matter.

The nutshell

• Side-plumbed preferred, or as second best, top-plumbed with stainless steel flex lines


• Earthquake-strapped with heavy bands lagged to wall studs in places that this is an issue


• Hot and cold shutoff valves if it serves a multi-story building


• Ball valves used as shutoffs


• T&P installed so that it can be easily disconnected from the water heater and drain line and replaced


• Recirculation pump (if there is one) valved for flushing
  
• Vent pipe sections fastened with sheetmetal screws, NOT tape


• Thermostat set at 130 degrees

The why behind the what

If you're installing a commercial tank with a view to service, the key is being able to quickly get into and out of the tank and that means being able to easily remove the cover. The chief cost of service is labor. If the plumbing is in the way, that slows everything down.

For that reason, we like side-plumbed tanks, if there is room for them. Another advantage is that if a connection leaks, there's at least a chance that the water will drip on the floor instead of on the water heater, which has little external rust protection. Further, if you're vacuuming and you've accidentally drained too much water out (the Muck-Vac depends on a full tank), you can easily add more just by opening a valve.

As to top-plumbed, we prefer the use of stainless steel flex lines. The truth is, there really isn't an optimal connector. Unions are prone to leak. Flexes can leak. And often, screwing copper fittings directly onto even a plastic-lined nipple results in electrolysis and leaks. But flexes can be moved aside after disconnection, and the stainless steel stays flexible. Unions are about hopeless to get off, and there is usually no "give" in the piping to enable removal of the cover.

In California, the straps have been code since 1992 for new and replacement tanks. But often, we've either seen no straps or flimsy ones of plumber's tape screwed into the plasterboard. Blocking behind a tank is not code, but we think it's a good idea if there's enough room for a tank to rock.

If a tank is on a lower floor of a multi-story building, and there is no hot shut-off valve, then when it is opened, all the water in the upper piping is going to run out there, complicating service and making it take longer. That makes it more expensive. Ball valves are not infallible, but they are generally more reliable than gate valves.

The treatment of the T&P is based on our belief that it should be regularly tested and replaced if it doesn't work properly. That's easier if it can be easily disconnected from the drain line and unscrewed.

We've created a recirc page with a diagram and photographic examples to illustrate our thinking on this, but it's important to flush air from the system after a tank has been opened. Our configuration facilitates that.

We've run across about 20 fallen vents and countless others that were in danger of falling. Sometimes it was because someone had merely shoved the sections together, others because they had been taped together and the tape failed. If three screws per section are used, it's much less likely that a vent can fall down or even be knocked down.

A thermostat setting of 130 is a tradeoff temperature. Legionella bacteria that cause Legionnaire's disease have been found growing in tanks set at 120. The bacteria can be inhaled as mist during a shower. Much above 130 and there is considerable risk of scalding and related injuries, such as falls.