aaronm wrote:I guess the only place to hang one's hat is on the current codes and mfg.'s installation instructions.
Aaron, especially in the case of a newer appliance in an older construction building.
In such a case, it may be prudent to place the higher priority on the manufacturer's installation instructions as the system (in this case the clothes dryer duct) may be treated as an 'unknown'/'unconfirmed' (after all, the only visible parts would be the connection of the flexible or rigid dryer connector to the dryer duct, and the dryer duct cap at the exhaust end of the duct).
Is the clothes dryer correctly installed to the dryer duct, size and type of connector to duct)?
Is the dryer cap at the exhaust end correct?
The length (also type and size) of the dryer duct is unknown/unconfirmed.