Incorrect Super Heat for TXVs in 1.5, 2 and 2.5 Ton Residential Furnace Coils
Type: Service Alert
Recall or Alert Date: 07-03-2014
Serial Number: DSB 14-0008d
Brands Affected: Carrier
Ongoing testing and reports from the field indicate that 1.5, 2 and 2.5 ton Thermostatic Expansion Valves (TXV) currently used in the above listed furnace coil products may not maintain the correct Super Heat (SH) in certain situations. The end result can be a lack of cooling for the homeowner due to a frozen furnace coil and this has been diagnosed in the field by high SH and low suction pressures measured at the outdoor unit.
Internal and field testing have confirmed that this is a start-up only issue and not caused by the TXV or furnace coil. The TXV is acting as a filter and is capturing an undefined “sticky” substance, which is causing the TXV to operate improperly. Internal testing has confirmed that replacing a TXV after a field failure resolves the issue except in a very small number of cases where other system issues may be present, such as airflow or installation. Replacing the factory installed TXV at the time of furnace coil installation does not prevent the customer from experiencing the issue.Affected Products: