Specifications

PCA
5.10 Calibrate Draft
(For PCA Models 15, 25, 35, 45, 55 & 65)
Material Required:
Calibration
• Calibration Fixture (Section 5-2)
• Bellows (adjustable)
• Micromanometer Range: ±8 in. H
2
O column (±20 mb)
Accuracy: ±0.01 in. H
2
O column (±0.025 mb)
Procedure:
Important! In Step 1, do not connect the draft calibration
fixture to the analyzer until the Calibrate Draft Screen has
been selected and displayed.
1. Enter the Calibrate Menu Screen per Section 5.3. Then choose to
calibrate the draft sensor.
2. With the Calibrate Draft Screen displayed, connect the hose from the
calibration fixture to the analyzer’s DRAFT port; then adjust the
bellows for a micromanometer reading of –4" H
2
O column (–10 mb).
3. Wait until the MEASURED reading on the screen stabilizes. Then use
the st and ENTER keys to enter an APPLIED reading* which equals
the Micromanometer reading.
Typical CALIBRATE DRAFT Screen During Calibration Procedure:
CALIBRATE DRAFT
MEASURED - 9.00 WC
APPLIED - 4.00 WC
4. Press the RUN key to calibrate the analyzer’s MEASURED value to that
of the APPLIED value. At this time the Calibrate Menu Screen is
redisplayed.
* The draft calibration range is from –2 to –6 inches of water column
(–5
to –15 mb), any attempt to calibrate outside this range will cause
the analyzer to display the message BAD CALIBRATION ENTRY.
Instruction 0024-9219 5-11