Trouble with one of Frank Lloyd Wright's radiant systems!

Weezbo

then there are actually ways to pipe things that might seem normal at a glance however produce problems...i know you have seen alot over the years so i would ask you if the pumps are possibly fighting oneanother...maybe having the baseboard on two zones and one pump provided it meets your requirements would be a start . then you could crank up the two fin zones and run it for a day ,if you have no problem surfacing ...then turn your attention to the radiant. if you find an air leak in the upstairs zone it could be letting air In rather than leak water out depending once again on how it is piped.

Paul Penfield

gurgling pipes

Hey guys, I need some advice. This house I have was designed for my dad by Frank Lloyd Wright in 1953. Last year I finished restoring it and opened it as a guesthouse. Wright was famous for using slab-floor heat, and so far the soft-copper 3/4 tubing has held up well--touch wood!!!

Here's the thing: lately the system has become noisy. It gurgles all night and keeps guests awake. I won't pretend to be a hydronics expert, but I've put in 20 years in the plumbing trade and I know when something ain't right.

The layout works like this: the slab, poured in 1955, has three loops on one circuit. A separate fin-tube circuit heats the downstairs perimeter. The upstairs circuit is modern fin-tube. All three are activated by Grundfos circulators off a Vaillant gas boiler with Tekmar controls.

Obviously it's air, but how's it getting in there and why can't we get it out? I've installed automatic air purges on the upstairs fin-tube and a spirovent off the boiler supply and last night it even woke me up, and I was wearing ear plugs! My supply-house consultant doesn't think its a leak because the system holds 15-25 psi and heats the house well. I'm tired of throwing parts at this problem; are there any tests I do to take the guesswork out of this?

Dave Meers

sounds like air

Hi Paul,

Big fan of Frank. Where are the three pumps located in relation to the expansion tank connection? Do you hear air being vented from any of your automatic devices? You may be venting out one and sucking in another, with the air gurgling its way around your system.

Are you familiar with Dan's book Pumping Away? The location of the circulator can be very important to some systems, especially with high head pumps like Grundfos.

Let us know.

Best regards, Pat

hr

Does the system really hold pressure?

Or does it have an auto fill valve? If it does have a water connection with a fill valve, shut this off and monitor the pressure for a few hours or maybe a day.

It could have a very slow leak and the fill valve keeps dumping water to it as it falls below 12 psi or so. Any slab cracks or shifting anywhere?

Personally I feel there is a life expectancy to copper radiant. You could be at, or beyond, that point, depending on how it was installed. the concrete itself, moisture in or below the slab, and slab structural condition all need to be considered.

hot rod

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Ken_8

Paul,

The FLW home I am working on had two problems. One was the steel (not copper) pipes that rotted away - destroying the system, and was pumping the opposite from what we all know now to be the "correct" manner. A B&G S-100 however can be installed "backwards" with little to no problems because the head pressure is so low. The Grundfos wet rotor pumps have much higher head pressure and the dynamic flow rates, especially having three of those things, would be problematic if in backwards.

The noise you hear is likely air, but with a smaller FLW design, may be velocity based, not air!

Get out your digital camera and show us a 600 X something pixel picture of the boiler, near boiler piping and those 3 Grundfos pumps. The size of the house is helpful as well. The BTU input of the boiler is good to know as well.

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Bruce M.

Paul, How was the sytem when FLW designed it?

What type of circulators were originally installed? What type of vent? Did the system work fine previously? Tell us a little more.