Duct Or Flex ?

odellconstruct

http://www.lanair.com/Lanair2.0/prod...?index=MXD-200

heres my questions how would you properly duct this unit into 3 rooms ,the first room is where the unit is located in a garage with 2 garage doors , second is a office next to garage office space approx 12x12 ft . and then a show room wich is aprox 12 X50 ft the building is a l shape with garage on side .

the building is a lil over 3,000 sq ft

this unit is already installed .. the last 2 heat reg does not get any heat out of . unit is tied into existing flex ducts . wich i believe are 6" in dia comes out 8'' at unit ..

blower rating is 1550 cfm is this enough , the fan speed is set on max setting . has a 3 stage motor for speed , the run is approx 40- 50 lf from unit ..wich is all flex .. does this unit need to be all hard duct to run effieciently to evenly disperse the the hot air .... came across this and has had me thinking how this would be corrected .. any suggestions

nhmaster3015

Not enough information to answer the question. Need heat loss\gain calculations. Need detailed floor plan showing door and window locations as well as north alignment.

MechAcc

You stated the trunk duct is only 8 inches????? Or did you mean 18 inches? First flex duct even when properly installed has twice the friction to flow as steel pipe. 50 feet of flex would have the same resistance as 100 feet of steel pipe. Rule of thumb chart for 18 inch steel is 1500 CFM. For 1550 CFM would not go smaller than 18 inch round. Install balancing dampers in each supply pipe.

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Dr Heat

First flex duct even when properly installed has twice the friction to flow as steel pipe. 50 feet of flex would have the same resistance as 100 feet of steel pipe.

According to the ductolator flex is 80% of hard pipe.

1550 is just lite of four ton and I think a bit small for 3000 sqft gar.
but you really have not given enough info