Wrestling the unruly…

… PEX tubing. I better clarify this right away before the rumor mill starts grinding…

What exactly am I talking about? We shifted modes from the potable water and drain-waste-vent (DWV) plumbing to another kind of plumbing: The PEX tubing for our hydronic heating system.

While the garden apartment has a radiant floor slab, we have planned for small baseboard radiators on the 1st and 2nd floors. A network of half inch PEX tubing connects the radiators with the manifolds in the utility room.

Each radiator will have a supply line, delivering the hot water to the radiator, and a return line, delivering the cooled water back to the buffer tank of the hydronic heating system.

The catch is that we have to do this ten times for ten rooms on 1st floor, and again ten time for ten rooms on the 2nd floor. Then, multiply this by two (for the supply and return line) and you end up with 40 runs. That is a lot of PEX tubing to handle–PEX tubing that will not cooperate unless it is carefully un-coiled.

The first task was to drill holes through the 1st floor in the utility wall. These are the connections for the PEX tubing to the manifold in the utility room below. I had to carefully line up the holes with the manifold ports.

Having learned a lesson or two from the plumbing installation, we opted to insulate the PEX tubing right away. The purpose of the insulation is twofold.

  • The PEX should be protected from UV light. Because the walls will be open for a while to come, the insulation protects the tubing from any light source.
  • The insulation also helps us to deliver the heat where we need and want it — in the radiators. Because any heat loss from the tubing occurs within the conditioned space, it may be, strictly speaking, not much of a loss. Still, we would like to maximize the system performance by effectively delivering the hot water to the radiators.

We initially looked at running the PEX tubing through the walls. That would have involved a lot of drilling through studs and way too many difficult and tight turns.

The easier route was to run the tubing under the 1st floor ceiling to each room and down the wall to the planned radiator location.

The PEX for the 2nd floor radiators is a little more straightforward and less material-intensive. The tubing also runs under the 1st floor ceiling but is then routed upwards through the floor to each room.

The simplicity of the bare bone interior suddenly disappeared. The utility wall is packed with PEX and insulation snaking all over the place.

The high tech madness continues under the ceiling with tubing spidering out into all directions. Everything begins to resemble the interior of a space craft.

About Marcus de la fleur

Marcus is a Registered Landscape Architect with a horticultural degree from the School of Horticulture at the Royal Botanic Gardens, Kew, and a Masters in Landscape Architecture from the University of Sheffield, UK. He developed a landscape based sustainable pilot project at 168 Elm Ave. in 2002, and has expanded his skill set to building science. Starting in 2009, Marcus applied the newly acquired expertise to the deep energy retrofit of his 100+ year old home in Chicago.

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