Chapter 3: Getting Started
Product Service 1-800-522-7658
21
Original instructions
Adjust the Fan Speeds and Confirm the
Performance of your Multi-Speed Blower/
Hood System
The MSB fan speeds need to be adjusted in the field to allow the hood to operate at
the proper face velocity. In order to adjust the blower to the proper speeds, refer to
the diagram in Figure 3-9 and follow the procedure below.
1.
Ensure the blower is turned on at the roof and the control circuit is installed
and powered up.
2.
Refer to Figure 3-9 and place the blower switch on the hood to its
maximum position.
3.
Locate the Intelli-Sense MSB Control Box on top of the fume hood. With a
small jewelers screw driver, adjust the MSB “MAX” setting and measure
the fume hood airflow with a thermal anemometer at the proper sash height
setting. Readjust the MSB “MAX” setting as required to set the face
velocity. Counter-clockwise rotation increases the blower speed and
corresponding fume hood airflow (CFM) increase.
4.
It will be necessary to check the blower wheel shaft speed by removing the
weathercover to confirm operation per the blower airflow charts in Chapter 4.
HINT: Many times a manual damper is used in the exhaust for
fine tuning and operating in the proper portion of the blower
airflow chart. For lower airflow volume (CFM) at any RPM,
close the damper. Refer to Appendix E that shows a manual
damper. Refer to Appendix D that shows a typical blower
operating curve with the damper adjusted to different positions.
5.
Repeat steps 3 and 4 for MSB “MED/MIN” speed. Decide if operation is
for medium or minimum based on fume hood sash position. If “OFF” is
desired, then turn “MED/MIN” to lowest setting.
6.
Repeat steps 3 and 4 for MSB “MIN/OFF” speed. Decide if operation is for
“minimum” or “OFF” based on fume hood sash position and fume hood
airflow requirements.
7.
Cycle hood at each blower switch setting and confirm airflow
requirements. If necessary, confirm blower shaft RPM on the roof and
confirm with blower performance charts in Chapter 4.
8.
With fume hood air monitor installed, calibrate airflow monitor and
confirm airflow at each speed setting.
9.
Replace weathercover over the ECM motor.
!
Summary of Contents for 7061110
Page 36: ...Chapter 5 Using Your Blower Product Service 1 800 522 7658 32 Original instructions...
Page 48: ...Chapter 7 Modifying Your Blower Product Service 1 800 522 7658 44 Original instructions...
Page 58: ...Chapter 9 Troubleshooting Product Service 1 800 522 7658 54 Original instructions...
Page 62: ...Product Service 1 800 522 7658 58 APPENDIX B BLOWER DIMENSIONS...
Page 63: ...Appendix B Blower Dimensions Product Service 1 800 522 7658 59 Original instructions...
Page 64: ...Appendix B Blower Dimensions Product Service 1 800 522 7658 60 Original instructions...
Page 72: ...Product Service 1 800 522 7658 68 APPENDIX F TYPICAL PERCHLORIC ACID HOOD INSTALLATION DIAGRAM...
