The heat is on!

The big day has come. The hydronic heating system is filled with water and Mariusz has come out to start up the system.

He switches everything on and tinkers around with the controls on the boiler. He keeps tinkering but the system just doesn’t want to start up. Should I worry about this?

Sometimes there are simple solutions to apparently complicated problems. As we were getting nowhere, Mariusz took a step back (literally – he stepped out of the utility room) to look at the big picture. I then saw the light bulb coming on. He stepped over to the shut-off valve at the water main and opened it. Of course! A hydronic heating system won’t work without water!

Within seconds the boiler fired up (which is hard to hear because it is so quiet). The pressure gauges kicked in and the pumps began to work, and with a lot of gurgling in the pipes. The temperature gauges at the storage tanks started to climb and the hot water began to flow.

We could see and feel the water running through the PEX loops that feed the radiant floor. I had fun watching Mariusz calibrate the flow rate for each loop at the manifold.

We had, however, two loops that for some reason had no water flowing. That sort of freaked me out. I already saw myself breaking up the new concrete floor trying to find the flaw in the PEX tubing!
Thank God, there was again a simple solution to the problem – a problem that I had caused.

The inlet and outlet for each radiant floor loop are right next to each other, with the exception of the two non-working loops. Here I had placed the two inlets and two outlets side by side.


That meant that the hot water was pushing in from both ends, or trying to get out from both ends. After consulting with Peter, Mariusz quickly identified the problem, switched the PEX connections around and got the hot water flowing.

I can’t tell you how nice it feels to have this nice, warm radiant concrete floor in the basement! The dog likes it too!


Happy Holidays!

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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