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Radiant Floor Heating/Voyager combi DHW and radiant floor heating problems


I live in condo housing in Fort Collins, CO, and share responsibility for heating issues.  We have radiant floor heating for our 7 buildings (3 or 4 to 6 or 7 units per building), with Voyager boilers and Pex under-floor heating tubes as well as domestic hot water heating (development built and heating system installed in 1999-2000).  
In the past couple of years, both unit heating and domestic hot water are not keeping up in one of the buildings (with 4 units and a 130,000 BTU/55 gal. tank Voyager boiler).  There is a clear correlation between outside temperature and inability to keep up with both.  We have had a heat loss assessment done that we are told indicates (we do not have paper work) that boiler should be 175,000 BTU (instead of the 130,000 we now have.
My SUSPECTS for problem are: 1. insufficient heating capacity; 2. radiant floor loops probably were installed in series rather than parallel (building by building, so last building gets coldest water); 3. balancing mechanism (crude simple valve adjustment) may not be serving us properly; and/or 4. mixing valve may be intermittently acting up.

We sort out many radiant floor and combi heating systems and suspect you are right about your various issues, but I would have to have more information and time to evaluate the problem before recommending any solution.

Please forward and CAD or pdf of the building. Pictures of buildings and equipment would be handy.

A consultation should help.

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Morgan M. Audetat


Radiant panel heating design, including floors and ceilings, European wall panels and snow melting for residential and light commercial buildings..............................................................-Master of Steam and Hot Water,City of Minneapolis....................................................--- Master Plumber, State of Minnesota...........


30 years..... Charter Board Member - Radiant Panel Association, former manufacturer of condensing boilers, former national distributor of radiant floor products, son and apprentice of mechanical & plumbing contractor. Current mechanical/plumbing contractor specializing in hydronic based, integrated HVAC systems. Radiant floor heating/cooling. Snow Melting. Condensing Boilers. Indirect water heaters. System design, consulting and technical training world-wide. Licensed contractor, designer, installer and consultant.

B.S. University WI 1981 CONTINUING EDUCATION: Viessmann Condensing boiler and Solar water heating certification 2010, N.D.S.U. Lead Worker RRP certification 2010, Knight condensing boiler certification 2009, Wrightsoft Manual J CAD certification 2009, RPA Designer & Installer Certification 2008, Nate Hydronic/Forced Air Certification 2008, Uponor/Wirsbo advanced design school certification 2007, Buderus Wall-hung certification 2007, Power Limited License (low voltage controls) 40 CE credits 2005, Basic Hydronic Certification IPEX & Northern Alberta Institute of Technology 1998, Charter Board Member - Radiant Panel Association 1994, Residential Off-Electric to Hydronic Conversion Heating School Canadian Hydronics Council 1994, B&G Little Red School House 1993, Rood Utilities (now Auburn Technical Institute) Oil Burner School 1993 ,Tekmar Controls residential and commercial 1993, Division Manager and Advanced Hydronic Seminar Instructor for the first Exclusively Hydronic Radiant Floor Distributor in the USA 1990, Hydronic Radiant Heating Association Workshop participant with Richard c. Bourne, PE spring 1988, Master Plumbing, Hydronic, Solar Course Red Rocks Community College 1987.

Awards and Honors
2009 System Showcase Award - Radiant Panel Association

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