New 34.5″ Chassis High Efficiency Furnace Venting Tableby HVAC Distributors May 6, 2015
Goodman recently issued Service Bulletin SF-064 to provide updated venting tables for the 34.5″ furnaces.
It is important to note that this service bulletin pertains to furnace venting tables for the models specified in it. While the bulletin stresses the importance of using the most current venting tables available, it is NOT stating that any furnace installed using an outdated vent table should be changed. Re-piping the venting of a furnace where the tables do not agree should ONLY be done if there is an issue where the vent is proven to be a problem.
We have recently had changes to many of our venting tables for 34.5” chassis furnaces. Since the launch of our new furnace line in 2014 we have changed some figures for minimum pipe diameter and maximum allowable linear feet of venting as well as the maximum number of elbows allowed.
In some instances the installation manual shipped with a furnace may not be the most up to date version. Current installation manuals are available on the following websites: www.daikincomfort.com, www.amana-hac.com and www.goodmanmfg.com.
When planning and sizing vent systems, especially when long vent lengths may be necessary, please refer to the venting table in the latest installation manual available. The following chart shows literature numbers for installation manuals with current vent tables at the time of this writing:
In the event of a furnace installed with a vent system meeting the requirements of the installation manual vent table that shipped with the furnace, but does not meet the current installation manual vent table requirements for vent diameter, length and number of elbows, no action is necessary unless furnace operation has been negatively impacted due to the vent system. If furnace operation is unreliable due to vent length, diameter, elbows installed per a pre-revised venting table, the venting should be reworked to comply with the vent table in the current installation manual in the chart above.
HVAC Distributors’ customers with questions or concerns can contact HVAC Technical Service.