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Manufactured Housing Furnace
Inspection Program Safety Notice
 Models
: Coleman, Coleman Evcon, & Red T Model numbers, DGAT070xxx (70,000btuh input)
& DGAT075xxx (75,000btuh input) natural and propane, Manufactured Housing gas
furnaces, manufactured during 1997, 1998, & 1999.
Based on several reported premature heat exchanger failures on the above
listed furnaces in Alberta, Canada, the Alberta Canada Municipal Affairs, Safety
Services Agency issued a January 30, 2002 Consumer Advisory, advising that
furnaces installed in the Alberta province, be inspected and serviced by a
qualified person. Furnaces involved were found to have heat exchanger cracking,
burn through, and in extreme cases, furnace wrapper burn through.
These situations, if left unresolved, can lead to significant property
damage, personal injury and/or death.
Since the publication of the Consumer Advisory, YORK has initiated extensive
field and factory testing. In all cases, testing revealed that pre-mature heat
exchanger cracking, burn-through and furnace wrapper burn through are not a
result of furnace manufacturing quality, or design, but instead, a direct result
of the following installation and/ or application related issues:
- Furnace heat exchanger temperature rises that are significantly above the
45-75°F temperature rise data published on the DGAT furnace rating plate.
- Restricted indoor blower airflow as a result of high external duct system
and filter static pressures. Many installations with cracked heat exchangers
were observed to have high static HEPA, or Electro-Static, after-market air
filters installed. In addition, many furnaces with cracked heat exchangers were
installed on very small, restricted ductwork. The small ductwork itself can be
restrictive enough to cause the furnace to operate above its listed maximum
static rating.
U.S. Manufactured Housing Manufacturer’s are required in new construction to
have duct systems pass HUD duct design requirements, which state that the total
duct external static pressure can not exceed 90% of the furnace nameplate
external static pressure requirement. Canadian Manufactured Housing Manufacturers
presently are not presently required to comply with this HUD-type requirement.
Older Manufactured Housing retrofits frequently have overly restrictive
ductwork as well, and this installation condition must be addressed by the
installation contractor.
- Furnace input over-firing, based on manifold pressure settings and
installation. Furnace inputs must always be de-rated by orifice change, for elevations
above 2,000 ft. above sea level.
To assist technicians in the furnace inspection process, YORK has developed
and distributed a detailed DGAT070 & DGAT075 service inspection sheet. This
inspection sheet specifically guides the technician on heat exchanger
inspection, as well as guides the technician on a step-by-step inspection of the
three potential furnace installation problem areas listed above.
If a heat exchanger is found to be cracked, it is very important that an
inspection of the installation be performed, BEFORE a heat exchanger or the
furnace is replaced. Failure to do so, can lead to rapidly re-occurring heat
exchanger failures, significant damage to property, personal injury, and/or
death.
Mandatory furnace de-rating may be necessary to compensate for high altitude,
or overly restrictive manufactured housing ductwork to allow furnaces to comply
with published 45-75°F heat exchanger temperature rise data.
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