Small job = BIG VALUE

By Bob "Hot Rod" Rohr

Radiant expert

This month, let's look at hydronic heat sources for limited space applications. My favorite job is a quick installation of a nice system that adds BIG value. I make money and my customers are comfortable and happy.

Here are some ideas for powering a small hydronic system. I've pictured a couple of options for gas, liquid propane (LP), oil or electrically powered systems.

On the electric side, Laing Pump manufactures a compact, well-built two Kilowatt heater and pump combination package. Two kW will provide the installer with approximately 6,800 Btu/h. Not unlike many other heaters of European origin, the EH-2 (two kW at 230V) package is limited to 167 F. That is plenty of temperature to drive most radiant, panel radiator or properly designed and sized baseboard fin tube systems. The circulator is built into the bottom of the stainless steel heater tube with no assembly or piping required. The EH-2 is built of all non-ferrous components should you be faced with a non-barrier tubing installation.  Sweet. In addition to an integral thermostat, the EH-2 has a thermal overload and a connection strip for a thermostat signal. The 1/2 NPT connections are provided at the supply and return ports.

I have used this Laing unit with a few multi-zoned system, for example, in a two bathroom home installation. I've placed it in both new and retrofit applications. The unit is only available in 230 volt. As such, a 20-amp circuit will be adequate for the two kW size. Snoop around their German site for a full line up of what they manufacture -- keeping in mind not all their products are stocked here in the USA. I have been able to fit a two-zone package in a basic off-the-shelf electrical enclosure for a nice tidy "in-the-box" package. Fasten it to the wall, make the PEX connections, fill, purge and plug in for hydronic comfort.

Contact a Laing dealer or manufacturer's rep in your area for availability details. You can find easy-to-understand sales and technical information, and a good glimpse of their wide range of offerings at their easy-to-use Web site www.lainginc.com. Also, check out their small solar circulator. This is a nice, smart circulator for PV powered systems.

With enough interest I suspect Laing would make more of these unique products available in the U.S. market. So, let them know what you think.

Even on my small one or two-zone radiant bath projects, I stay with a hydronic system. With a hydronic installation the homeowner could add additional hydronic or radiant and upgrade to a boiler package if and when the load dictates. Often my customers shun LP in their home, so the small electric pump/heater packages fit nicely.

About 15 years ago Bradford White offered another unique product to the hydronic industry; it was called the CombiCor. Bradford White basically inserted a coil inside both their 50- and 75-gallon tank to provide both a dhw source and heat exchanger to drive some hydronic loads.

The concept was interesting and allowed a fair amount of DHW and some hydronic capacity from a single, small footprint appliance. The unique coil also had a provision to provide a double walled protection with a leak-detection provision at the hydronic connection. I thought the concept was a good one. My experience showed the coil construction wasn't quite up to the task, unfortunately. Few of the ones I installed made it to the 10-year mark.

Bradford White has gone back to the drawing board and made some needed improvements to this heater. Now caller the Combi2, the heater is built with a large, 1-1/2 inch diameter enameled steel coil. This should solve both the longevity issue, while at the same time reducing the pressure drop that challenged the earlier 5/8"diameter heat exchanger in the first version CombiCor.

For an application where floor space and flue capacity is limited, the Combi 2 allows you to replace the current existing water heater and provide an option for up to 50,000 Btu of hydronic output. The Combi 2 also ships with a thermostatic three-way mix valve for the domestic side temperature protection. This allows you to run the tank temperature higher for additional hx output. A side benefit with a tank temperature in excess of 140 F could be a protection from legionella potential. For more information, visit online at www.bradfordwhite.com.

I have shown a Combi 2 that I pre-assembled with the hydronic side components in my shop. I use a CSST (corrugated stainless steel) manifold to provide a nice clean manifold for the fill point, expansion tank and pressure gauge. With good full port purge ports, I have found a small air vent at the high point is adequate for air elimination.

As a one-man shop, I'm attracted to these small radiant jobs that can be installed "turn-key" in just a couple days time. I've discovered this is a very profitable niche. I rarely get a "no" for an answer when I offer to warm the bathroom floors and shower walls. I can't think of a better way to introduce homeowners to the world of radiant.

Bob “Hot Rod” Rohr is particularly interested in “hybrid” radiant systems – systems that utilize solar and wood energy in addition to, or in place of, fossil fuel. Also, systems that incorporate different methods of heat delivery. He owns and operates Show Me Radiant Heat and Solar, Inc. in southwest Missouri. Reach hot rod at hotrodradiant@aol.com or by phone at (417) 753-3998.