Simple systems
By Paul Rohrs, Radiant Expert,
Biggerstaff Radiant Solutions, Lincoln, Neb.
The process contractors go through to procure and complete a large job can be very gratifying. You design the system, write the proposal, land the job, install it, commission the system, and deposit the check that keeps your bottom line in the black. These jobs can range from boiler change-outs on commercial projects, to full-blown radiant floor heat systems in Mega McMansions.
While I enjoy landing, designing, and installing the systems for McMansions, I also love the small simple systems. I piped a system the other day and after completing it, I stood back and realized how much I really enjoyed the simplicity of it. This system was for a small 19 x 19 garage that was going to be used as a woodworking shop. The owner needed a very small but responsive system and the primary issue was budget. It was an existing garage with concrete floors. There was going to be quite a bit of equipment filling this shop and each piece of woodworking equipment would be movable so that the owner could bring out a piece of equipment, use it, and return it to its resting place. With woodworking equipment lining the perimeter of this shop, it was clear that the required 30-plus feet of baseboard was not going to be a practical design feature. In-floor heat was going to be a budget breaker because that would require saw cutting out the old concrete, installing the tubing and pouring it back. The homeowner also did not want forced air heat or any heat source with an open flame as a potential ignition source as he would be using stains and varnishes in the finishing process.
The owner’s intention was to keep the shop at 62°F during the workday, and then set it back to 52°F at night. This also then dictated a system requiring a fairly quick response time. With design conditions at –4°F, and wanting to run the lowest temps possible so as not to penalize the owner with high fuel bills, it steered the equipment selection to a small electric boiler and the largest panel radiators available without wrecking the budget. The plan also included no make-up water or fill-valve. This was to be a stand-alone system that if water needed to be added, it would have to be done manually.
Figure 1 illustrates the basics of the system. The low-pressure drop through the boiler and the panel rads allowed me to install a single pump to service the system. We are still pumping away from the point-of-no-pressure-change directly into the panel radiators.
Figure 2 shows the electronics of the system. While the boiler had the potential to run the system pump and thermostat, I like to electrically separate components with an inexpensive single pump relay and just use the pump relay end-switch for a simple signal for boiler heat. Trouble-shooting this system will always be simple. The thermostat calls for heat, the pump relay engages the pump and the pump relay end-switch calls for heat to the boiler thermostat terminals. Then the boiler’s internal controls check the outdoor temperature, and set a target temp. The boiler then feeds electricity to the elements until the target temperature is met or the thermostat is satisfied.
Figure 3 is a picture of the newly commissioned system. There is still some final insulation to install, but this system is ready to go. As convective airflow over the panel radiators is key for proper heating, the owner will have to get into the habit of shop vacuuming out the panel radiators and using a brush (when necessary) if excessive sawdust is generated.
This system was a bit of a departure for me in that I am so used to installing tubing and having a high mass system with large amounts of comfort and a slow, but even response time. This system’s small water content (approximately six gallons) really illustrated to me how responsive low mass radiant can be. When the thermostat satisfied at 62°F and ended the call for heat, the panel radiators continued to emit heat and sustain a long off time much like a radiant floor heat system.
Install time was about 10 hours and only took a few minutes to purge and fill. The small amount of install time was directly related to: 1.) The amount of piping between the two panel radiators and electric boiler, and 2.) That I didn’t have to contend with venting or gas piping. Another benefit to this small system was that my local mechanical codes didn’t require me to pull a permit. The local city inspectors inspect for backflow prevention, combustion air and gas piping, none of which were on this project. The licensed electrician on the job took care of his necessary electrical permits.
I would enjoy doing one of these simple systems a week. They are relatively inexpensive and very simple to install, as well as they really can shine a spotlight on the radiant industry to what is available to owners needing inexpensive systems. It reminds me that I started out designing systems like these before graduating to large more complex systems. If you have a large shop with multiple teams, consider these installs for your rookies. It is a simple way to learn the basic tenants of radiant and with a carefully thought out plan, it will leave little room for rookie mistakes. Another benefit of this system was that I spaced this out over a couple of days. It left me time to do service calls, billing, and other proposals. I am not saying that I don’t want to continue to land the big jobs, but landing these smaller jobs may provide a little more balance.
These “McMini” systems are a far cry smaller than the McMansions that consume a lot of equipment and man-hours, but these projects are out there and can add to your bottom line, as well as polish the skills of younger workers. These small systems add value in the industry as they can be fine examples of well-done radiant at a budget price. Don’t believe me? The Radiant Panel Associations “System Showcase” awards have a separate category for “Simple Systems.” Now what more motivation do you need to go out and secure these fun little projects? Ready, Set, Go!
Paul Rohrs welcomes your comments. Contact Paul at paul@biggerstaffradiantsolutions.com.