If the Pyrex sight glass (located in the right-hand side of the combustion blower motor mounting flanges) is missing, gas / flue products will be introduced into the burner compartment.
If the sight glass is not present, equipment service may be temporarily reinstated by removing the combustion blower motor and inserting two pennies into the milled area of the flange that normally holds the sight glass.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.