ID AND FD Fans Startup in a Balanced Draft

S

Thread Starter

Shirley

The question is we have a balanced draft furnace in one of our projects. I understand...During start up the id fan is started first and then the fd fan. My question is in one of the projects I found that they were using the cold and hot air doors open condition near the fd fan to start permissive for cold start of a ID. In other project the hot and cold air open condition is permissive for cold start of fd fan. Please note both the projects mentioned above are balanced draft furnace. Kindly explain which of the above procedure or permissive is right.

Thanks and regards
Shirley
 
Shirley... unless otherwise required by the manufacturer, and your facility conforms to NFPA regulations, the FD-fan should be started first for both the Cold- and Hot-Start.

This is to insure an open-flow path from the FD-fan inlet through the stack, thus preventing Furnace Implosion!

Regards,
Phil Corso.
 
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