Radiant Floor Heating/Replacing a CombiCore


Our cabin in NW Wi has an 11 year old Bradford White (65mBTU)LP combicore that has developed a leak.  We keep the structure (940 sq. ft.)heated in the winter at 50-55 degrees and warmer on weekends.  The cabin is 12 years old, heated slab on grade, vaulted ceiling, 6" walls and faces the North with a lot of glass.  This past year we used about 650 gallons of propane.  The Bradford White units are now about 3x what we paid originally.  A contractor in the area is recommending (with no heat load study) a Triangle Tube (Challenger Series)which is about the same cost as the Combicore but obviously all the piping would be replaced.  Do you have an opinion?

Badger Boiler Combi Cor Water Heater
Badger Boiler Combi Co  
We are Bradford White certified contractors here in Minneapolis and since we also specialize in radiant floor heating we get a lot of calls for warranty and new installation. The new Bradford White Combi is quite good though still an atmospheric, low-efficiency gas storage water heater.

If folks want to upgrade to a "GREENER" water heater we point them to a condensing Polaris and design sub-systems to separate potable from space heating. This gives our customers the sealed combustion, direct vent features of the condensing boiler but still provides plenty of domestic hot water at low cost of operation.

More pertinent to your question and fairly common situation. There is no condensing boiler with an output low enough, even at low-fire, to maintain both comfort and efficiency. Another reason a proper ACCA Manual 'J' heat load analysis is absolutely essential.

There is certainly nothing wrong with the Triangle Tube Challenger, but like so many combi-boilers and tankless water heaters, the peak demands for domestic hot water (DHW) usually far exceed the design condition demands for heating the same structure. I do not see this changing as houses have been getting progressively tighter and better insulated while DHW demands continue to grow.

We prefer the high-mass presented by a super-insulated water heater for the relatively low loads and often small zones that would short-cycle the average boiler or tankless water heater to an early grave. At the same time a bigger than  average tub can be filled or a couple of showers run continuously with the same combustion efficiency as a condensing tankless without particularly high installation or maintenance cost.

Even if you don't opt for high efficiency, a conventional water heater will serve and do better with improved controls including outdoor reset.  

Radiant Floor Heating

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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 owner---www.BadgerRadiantDesigns.com---Minneapolis 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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