SERVICING
S-203 AIR HANDLER EXTERNAL STATIC
To determine proper air movement, proceed as follows:
1.Using a draft gauge (inclined manometer), measure the static pressure of the return duct at the inlet of the unit, (Negative Pressure).
2.Measure the static pressure of the supply duct, (Positive Pressure).
3.Add the two readings together.
TOTAL EXTERNAL STATIC
NOTE: Both readings may be taken simultaneously and read directly on the manometer if so desired.
4. Consult proper table for quantity of air.
If external static pressure is being measured on a furnace to determine airflow, supply static must be taken between the "A" coil and the furnace.
TOTAL EXTERNAL STATIC
S-204 COIL STATIC PRESSURE DROP
1.Using a draft gauge (inclined manometer), connect the positive probe underneath the coil and the negative probe above the coil.
2.A direct reading can be taken of the static pressure drop across the coil.
3.Consult proper table for quantity of air.
STATIC PRESSURE DROP
If the total external static pressure and/or static pressure drop exceeds the maximum or minimum allowable statics, check for closed dampers, dirty filters, undersized or poorly laid out duct work.
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