Frank Lloyd Wright Home

Jim Armstrong

I have been involved with the rehabilitation of the heating system on a Frank Lloyd Wright home, that is on the national registry of historic places.

A wonderful designed home and heating system that includes radiant floor (slab) heat (Copper pipe) on the main level and baseboard on the second level.

When the mechanical room was redesigned the boiler was changed to a p/s piping system. Two zones (pumps), 1 for slab, the other for baseboard.

This is the background to the issue the heating system is experiencing. It originated about 3 weeks ago when a cartridge circulator burned itself out due to running dry. On the site, I could hear water pouring down the vertical lines and flowing through the pipes mixed with air. I suggested a Spirovent air eliminator be installed when the pump was replaced. That has been done.

System was refilled and seemed to work fine. Now there is the same noise. Air is gradually exiting the baseboard zone via an auto air vent on the second floor.

My question is a few parts...

1) is it possible for air to be migrating from the slab secondary loop into the second floor secondary loop without bypassing, and therefor being eliminated by, the Spirovent (Could a leak in the slab be introducing air into the system). I find this improbable due to the mixing device for the floor being a mechanical 3-way mixing valve.

2) Could this be air that was not purged at the time of filling. If so, why would it not be expelled through its normal course of flow through the Spirovent.

And finally, if the system was filled and purged properly (which is a variable at this point) is it possible that a leak in the floor can introduce air into the system and not cause a drop in pressure on the gauge (there is a PRV valve installed). Then find its way up to second floor where it is expelled by the air vent?

At this point I am thinking it was not filled and purged properly. I am currently running a crude test to check the glycol concentration levels over the course of a week to rule out any possible leaks. I could use a little input as to what I should be looking for as other possible causes.

As always, all advice is greatly appreciated!

J.C.A._3

My take.....

I would put a pressure test on both zones individually taking out all the related fill and purge piping, and test the feed/boiler seperately. If there is a leak in the emitters, you want to know NOW !

The end of the heating season is in sight. If there is a way of eliminating the culprit,you will more accurately begin the process of writing a proper proposal.

If the system was installed properly, it shouldn't be too big of a deal. If it was installed with no isolation valves, things could get complicated.

I ran into this once with the same type of design, but different material and boy was that a bugger! Found that the 1-1/4" MONNELL tubing installed in the concrete floor had a leak. After digging up the suspect area, we found that it was a fitting (cast iron coupling someone put in originally!!!) that was the culprit. Not an easy repair but worth the time it took to find, to the homeowner.As far as I know it's still going strong. Copper in concrete might not be as pretty by this time. Chris

jalcoplumb_2

Could have air ...

being sucked into the system throught the air vents. Try removing the vents and purging the system. The Spirovent should keep it air free.

Testing the system for leaks is a great idea. That copper could have sprung some leaks over years.

Doug Wagoner

I agree with

jalcoplumb. Eliminate the auto vent on the BB and replace with a manual vent. Pressurize the system to get five psi on 2nd floor BB, shut off the auto fill feature and watch the gage. It will tell you soon enough if there is a leak.

Jim Armstrong

Got it.

I went out to the job today, turns out to be a faulty PRV not adding the needed pressure to eliminate the air. Once the PRV was re-engaged, after 3 minutes all sounds of air wer eliminated, and our worries are gone!

mental burner man.

Boiler internal by-pass problems, simple way to check is to momentarily flip the circulator ( reverse the dir. of flow ) if this can be done watch flowchecks etc..
correcting by-pass probs. another story.
happy hunting.