IF it has a motor it is a Fire/Smoke damper. The motor is to close the damper when a smoke detector in the system detects smoke and the damper has a fusible link on the inside that will break when the internal air temperature gets too high allowing springs to close the damper independent of the...
Consider going with the recommended CFM requirement but calculate the pad areas in relation to the CFM and keep the air velocity across the pads low enough to not create carry over of the water on the pads. If remember it should be below 500 FPM velocity but you should check that number, it has...
Get the data / fan curve from the manufacturer of the fan.
What ever duct work, dampers etc. that is connected to the fan will determine the static pressure.
The velocity of the air in the duct will be determined by the duct size and how much air you are running through it.
Higher flow =...
Perhaps you could fabricate two "Y" fittings to transition from 12" round to two 8" round or smaller, and pass through the beam with two 8" round or less dia. if needed and on the other side go back to a single 12" round.
If there are any strainers on the chilled water lines to the unit make sure they are clean.
If the AHU has a bypass damper, make sure it is functioning properly.
Check for dirty air filters.
It looks like something Graingers might have sold long ago. I have seen similar things and they were soldering station and pc board work station or conformal coat stations. On the top of the hood is the exhaust fan, and inside the hood at the back area you see the filters, possibly with carbon...
Aaaargh! The file didn't show up in my last post, I will try again here.http://files.engineering.com/getfile.aspx?folder=b8dec6b4-51a3-4e6a-9f6c-0e587920a084&file=25_90_00_AHU-VAV-REV4-1.docx
Here is some information on this subject, maybe it could be helpful. It is from Penn State found on a web search. It is quite detailed and covers all situations, I think. Interesting reading. ;p
ROGZOG
I am trying to understand how the RA fan can control the building pressure instead of the relief/exhaust fan/damper.
Lets use a particular condition, say the unit is in economizer mode taking in outside air. As the unit brings in OA the building pressure goes high, the building pressure sensor...
Sorry, my bad, I re-read and see that the RA fan is linked to the building static, but I still wonder if you might still run into problems controlling the overall static pressure in the building related to the outside pressure.
ROGZOG
What about the building static pressure? Is it controlled? Couldn't you use the exhaust to control the building static? Too much OA and no relief and the building outside doors might not close correctly or too much relief/exhaust with not enough MUA and you might have to pull like hell to open...
I am just guessing here but are you having to drive the loads off the nose of the crank because of rotational direction for the pumps? If so, maybe you should consider some type of transmission or drive to change the rotation off of the tail of the crank where the motor was designed to take the...
Something else you might check is the negative pressure there and the depth of the trap. If the filters get too dirty and causes the negative pressure to get high and the trap is not deep enough the trap won't drain.
Just thought, does the insulation on the duct have vapor barrier? Is the vapor barrier sealed at all laps and joints? If not, the hummid warm outside air will condense on the cold duct and soak it.
rogzog
