Insert the anemometers
From the heat exchange box, two hoses go up to the MVD. One hose is for the
plenum air, the other for the 'volume' air. The volume air path is the
one with the big valve (V1) in it. Starting at the box, there is first
an elbow, then a short flexible section. This is where the anemometers
A1 and A2 are (temporarily) inserted. The readout should be set to m/s. Turn them
off when not in use - the batteries run out fast (3 AAA).
Turn on the fan
Turn down the LV supply that controls the fan speed.
Power up the fan with the software - this provides 110V power to the
fan motor.
Next turn up the fan with the LV supply. Read the velocities on the
anemometers. It should be 13.2 for the plenum, and 4.1 for the 'volume' air.
Balance the flows by manipulating the fan speed and the valve (V1) in the
volume supply line.
Neutralize the MVD pressure
The supply side of the air path (between the fan and the MVD) has more
impedance in it than the return side, between the MVD and the fan.
Therefore the pressure in the MVD tends to be a little negative.
There are 2 big valves (V2 and V3) in the lines coming out of the MVD, and by
partially closing them, you can increase the return-path impedance, until the
pressure inside the MVD is neutral.
Get the pressure meter (P) and a section of hose, long enough so that
you can look at the meter while manipulating the valves. Insert the hose
into the MVD through a small hole in the outer enclosure.
With the air running, slowly close both valves until the pressure
reads zero.
Close up the hole with a piece of rohacell, aluminum foil and tape.
Remove the anemometers
The anemometers are not designed for long-term use, since the bearings will
wear out. When you're done and everything is set up and written down, take
out the anemometers and replace them with the same-length inserts that are
made for this.
Same for the other half
Repeat steps 1-5 for the other half of the MVD.
This is another reason you need to remove the anemometers.