# Would like to lower CFM CHB105



## pawpie (2 mo ago)

Hello

I recently had a Williamson CHB-105 variable speed installed and would like to know if it's safe to put sw3 at position "C" to lower the CFM (Noisy when ramped up)

Nozzle 0.75 

SW3 currently at position "B" or 1070 CFM (when ramped up)
SW3 at position "C'" says it would be 960 CFM (page 45 of the manual)

Can I assume 960 cfm is safe to run as the variable speed fan will keep the CFM at 960 regardless of Duct size (May be a little undersized as built in the 50's)

Appreciate any input. According to the manual the temp rise would be at the high end of 85f

I don't care if it loses a little efficiency. Comfort and quiet more important to me.

Other dip switches settings: SW1 = "B", SW4 "B" SW2="B"

Thank you


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