Radiant heating can be found in many places, but it also can be improved.

A phone call led to a floating factory in need of improvement to its radiant system.


I’ve seen some unusual projects in my years as a radiant contractor in Seattle, but a recent project ranks as the most interesting and challenging. It also led to some new friendships.

When the phone rang in early May last year, I noticed the caller was from Gurian Instruments and presumed that the company built something related to marine hardware. The caller introduced himself as Michael, and told me he had drilled through a radiant pipe in the floor of his factory while installing a new electric line.

His address was a barge located on Salmon Bay about 1,000 feet behind my shop. I told the owner I could be there in a few minutes and took a short walk over to the barge. The hull was 36 feet by 105 feet, with a two-story metal-sided addition built on to it. I located the office on the second floor and introduced myself to the owner.

He looked familiar and spoke with a prominent “New York/Brooklyn” accent. But then everyone from New York looks familiar to me. He was wiry and intense, yet had a sense of calmness about him. We schmoozed for a few minutes and then I realized who he was. Michael Gurian was a prominent acoustic guitar maker and luthier who had moved to Seattle in the 1980s after a catastrophic fire in his factory destroyed all that he owned.

When I told him I recognized him from my musical past, he said, “You must play music if you know who I am.” The barge contains the factory where he now manufactures the instrument parts for guitars and mandolins that he supplies to most leading instrument makers and the larger guitar companies.

When he showed me the radiant system and the actual leak, I knew this wouldn’t be easy. The PEX used in the radiant slab was 22 millimeters and was discontinued by a Canadian manufacturer 10 years ago. Transition fittings or couplings were no longer available. After trying several types of brass insert fittings and clamps, the solution was to convert the splice to a 3/4-inch Uponor hePEX and make up the 22-millimeter ends using barbed brass couplings and a special stainless-steel banding clamp tool used by divers.

We borrowed the tool from a local dockside machinist. The fix worked. Gurian worked alongside me to assist and operate the banding clamp tool while we were on our knees, crouched beneath several large machine tools.

We then had time to review his 7-year-old system. He said he was unhappy with the workmanship and performance. Since natural gas was not available dockside, propane tanks had been installed at the end of the barge to serve the appliance requirements.

The existing stainless water heater was heating the 3,400-square-foot slab, an indirect DHW tank and two copper fin-tube baseboard zones. When I inquired about the radiant tubing design, I was told that three radiant loops, each exceeding 1,000 feet, were installed. But wait, there’s more!

One loop was crimped during installation; another loop was drilled by the same crew when installing a shower stall. That left one loop to heat the factory floor. The three-loop manifold was made with copper tees and sat below the installation without purge or balancing ports. The damaged loops had been disconnected.

A horizontal 53-gallon indirect DHW tank was suspended in the bilge on fabricated brackets (made by Michael Gurian) to maximize floor space for additional storage of hardwoods.

Improvements Needed

I admitted that the workmanship was certainly below average. Gurian is a perfectionist, and he expects the same of any subcontractor who works for him. I could understand his frustration, which he didn’t hesitate to share. Besides, the existing system had huge monthly fuel bills, disproportionate to what was possible on a highly insulated structure.

I was given a tour of the vessel, and the various machines and laser cutters that made guitar parts. The factory structure was built on top of the hull, using prefoamed panels and metal siding. The “basement” or bilge area under the main floor contained his sawmill and storage for many thousands of board feet of rare hardwoods, used in guitar part manufacturing.

He asked me to prepare a bid to replace the heating system and fix what wasn’t working. There were complaints that the baseboard zones were “never right.” Upon examining the piping method to install the baseboard, it was apparent to me that the installers tried to do a “Monoflo” one-pipe system, without using Monoflo tees. No wonder it wouldn’t put out much heat.

I told him I’d prepare a bid and get back to him within several days with a formal proposal. He than mentioned that there was a deadline - the barge was scheduled to be moved 300 feet down the dock at the end of June, and all mechanicals had to be completed before the barge was relocated.

Michael then invited me to the office lunchroom for an espresso. The espresso machine was rather impressive and he made me the best coffee I’ve had since moving to Seattle. The biggest distraction in the room was his large Hyacinth Macaw, who was anxious to make my acquaintance. Michael has several parrots, and I felt immediate kinship, being a parrot owner, and a former New Yorker.

I noticed the lunch crowd was a collection of local dockside personalities, particularly Dave, the machinist, an ex-navy diver. Everyone sat around drinking strong espresso and sharing stories of the “old days.”

Birds of a feather (left to right): Contractor Paul Pollets with Sam I Am (an Electus Parrot); customer Michael Gurian with Duke (a Hyacinth Mackaw); and Dave Clark, master machinist to the marine industry - just a few members of the "Curmudgeon's Coffee Klatch."

My bid was delivered and accepted within the week. Now, when I prepared the bid, the biggest obstacle was the size of the mechanical room, a scant 38 inches wide by 36 inches. To fit a wall-hung boiler with multizone piping would be hard to do, but not impossible. After prepping the room and re-painting, it was ready for the install in early June. We used a Viessmann Vitodens 8/32 boiler with a low loss header and carefully fabricated the zone piping to fit before we pressed the fittings. We used copper for the “near-boiler” piping and converted to PEX-AL-PEX in the ceiling above the room.

Locating the low loss header was the key for maximizing the small footprint. Since the radiant piping ran through the mechanical closet, the PEX piping in the floor had to be located before drilling holes for the indirect tank piping to be installed below. The piping was located without damage by carefully chipping through the structural slab.

We decided to install a horizontal Viessmann HoriCell 300 53-gallon tank under the mechanical room in the bilge below. The original 80-gallon indirect was taking up valuable floor space and the owner wanted more floor space for wood storage. Gurian fabricated special brackets to support the tank with ample headroom. The tank was carefully placed overhead in the brackets - by stronger men than I - and piped in, allowing access to the manhole on the front of the tank.

A three-way motorized valve was used for the radiant load and a separate pump with two-zone valves controlled the baseboard high-temp zones.

We fixed the baseboard zones by installing a reverse-return piping strategy, and piping in new PEX-AL-PEX returns, leaving the original copper piping as the “supply.”

The leaking loop in the radiant floor requires removal of the shower stall adjacent to the mechanical room. This is repairable. The crimped tube that was never “un-kinked” prior to the pour may be impossible to find, but I suspect the factory machines may emit adequate Btus to heat the space.

With the deadline fast approaching for moving the barge, we completed the heating system with time to spare. Gurian then asked if we’d do the water main extension and sewage ejector extension. The hard part was finding the proper 2-inch flexible sewer pipe that would be pressure-rated, UV-resistant and, more importantly, available on short order.

After several dozen phone calls, the sewer pipe was located and purchased. With three days till the barge move, the 1-inch Uponor AquaPex and the 2-inch sewer flex line were fished from the dock using an uncoiler to prevent kinking. Gurian guided the pipes through the piers sitting in a handmade “float boat.” Both lines were installed under water, with weights to hold the pipe down three to four feet under water. The barge was moved the day after the connections were made and without a hitch.

Gurian was relieved to meet the deadlines without factory interruption. He was highly complimentary of his new system and our problem-solving skills, and he’s a man who can be hard to please.

Now I’m a part of the daily “Curmudgeon’s Coffee Klatch” and get to share my stories, as well as listen to the fascinating stories of my new friends. Sometimes I bring over my parrot to socialize. It’s amazing what can be found in your backyard. Something old and something new.