Make-up air unit for boiler with variable speed FD fan
Make-up air unit for boiler with variable speed FD fan
(OP)
What types of approaches have others used to supply make-up air for boilers which have variable speed FD fans?
The boilers will have wide turn-down capability, with O2 trim, which means the forced draft (FD) fan is variable speed.
The code requires that a fixed rate of make-up air be supplied to the space, based on the installed capacity of the boiler.
My thought was to supply a constant amount, with a relief hood. The problem is in the winter I will be heating the make-up air to maintain a temperature in the space, and this will be a huge energy loss for all air that is exhausted, but can't be helped because the code is over simplified and requires that set amount outdoor air regardless of how much air the boilers require
Any ideas or experience with this?





RE: Make-up air unit for boiler with variable speed FD fan
RE: Make-up air unit for boiler with variable speed FD fan
you should consult the boiler manufacture on their requirements for that. Most give you some duct sizes for certain lengths.
RE: Make-up air unit for boiler with variable speed FD fan
knowledge is power