The internal silicone diaphragm is specifically rated for air and combustion by-products

and ProMax series

Its bi-directional design eliminates installation errors by allowing flow in either direction

This assembly is typically used in specific series where a 3/4" shaft diameter and DWD configuration are required for the blower motor interface

this module provides the precise HVAC burner control timing necessary for safe combustion

Nordyne 663734 Flexible Hose 321894-709 The internal silicone diaphragm isThe Nordyne 663734 Flexible Hose is a critical OEM replacement part engineered for high performance fuel delivery in Nortek and Nordyne heating systems. As a veteran grade flexible burner hose, this component is designed to facilitate a secure, vibration resistant connection between the fuel line and the burner assembly. This direct fit replacement ensures consistent HVAC fuel flow, effectively mitigating the risk of leaks and system malfunctions in