EWC Controls CLBD Service manual

Model CLBD
P/N 090375A0250 REV. E
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EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX [phone] E-Mail- [email protected] 1
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Constant Load ByPass Damper
The model CLBD Bypass Damper is an easy and economical way to manage system static pressure, in a zoned HVAC system.
Damper adjustment is easily achieved by increasing or decreasing the force applied to the bypass damper blade, until the
desired static pressure is achieved. See Page 2 for details.
Due to the constant load applied to the damper blade and the unique magnetic latch, the CLBD Bypass Damper can be installed
in any position on your bypass duct-work, to manage the HVAC system’s static pressure during zoned operations.
The CLBD minimizes bypass volume, while still preventing the HVAC system static pressure from rising above the selected
Static Pressure set-point.
The CLBD is a basic, cost effective Bypass Solution for Constant Speed or Variable Speed “zoned” HVAC systems.
Note: This drawing of the Bypass damper, Balancing Hand Damper, and Related duct work is intended to serve only as a guide. Your actual
duct work layout and components may differ. Use the graphic as a guide when planning or designing a Zone system regardless of the Equipment
type, Duct layout and Airflow configuration.
Supply Air
to
Zone Dampers
CLBD
CONSTANT LOAD
BYPASSDAMPER
Ultra-Zone™
HVAC
UNIT
Return Air
from
All Zones
Ultra-Zone™
Zone Control
Panel
Supply
Air
Sensor
RD-HD
Hand
Damper
(ifrequired)
CLBD
Ultra-Zone™
6ft. if possible 6ft. if possible
-
MODEL #
“B” Dimension
8"
10"
12"
14”
16"
CLBD 8
CLBD 10
CLBD 12
CLBD 14
CLBD 16
“A” Dimension
SIZE
8"
10"
12"
14”
16"
12”
12”
14”
16”
20”
Static Pressure
Adjustment Knob
Static Pressure
Set-Point Indicator Damper Blade
Position Indicator
A
B
MODEL #
8"
10"
12"
14”
16"
CLBD 8
CLBD 10
CLBD 12
CLBD 14
CLBD 16
CFM
SIZE
400
700
1100
1700
2200
Bypass CFM Chart

EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX [phone] E-Mail- [email protected]
2
BYPASS SIZING EXAMPLE ** see note belowBYPASS SIZING EXAMPLE ** see note below
1. Install the CLBD bypass damper in horizontal or vertical bypass duct.
2. Route the bypass airflow from the main supply air plenum or manifold back into the return duct as shown on
page 1. Or you can route the bypass airflow into a seldom used area or room that has a return air grille. Do Not
route bypass air into a non-conditioned area such as an attic or crawl space.
3. If possible, connect the bypass duct to the return duct, 6 feet (or more) away from the air handler.
4. If a Balancing Hand Damper is installed, you should balance the bypass duct first by referring to Application
Note #090376A0169D.
5. The CLBD comes factory set at 0.5”wc and will function correctly for most residential HVAC applications
right out of the box. No further adjustment is required. If necessary, follow the additional steps below.
6. Energize ALL zones to operate the HVAC system with the indoor fan running on the highest speed. (Usually
a cooling demand, 2nd stage if applicable). Confirm the CLBD is closed.
7. Next, turn off all larger cfm zones (one at a time) except the smallest cfm zone & wait for the zone dampers
to move fully closed or nearly closed, if they are adjusted to allow some leakage.
8. Now, monitor the airflow in the smallest zone.
* If there is to much airflow/noise in the smallest zone, adjust the CLBD static pressure setting lower.
* If there is insufficient airflow in the smallest zone, adjust the CLBD static pressure setting higher.
9. To adjust the CLBD, simply turn the “Adjustment Knob” to select a lower static pressure setting or a higher
static pressure setting.
10. Congratulations, your CLBD Bypass Damper is now properly adjusted.
CONSTANT LOAD BYPASS DAMPER INSTALLATION AND SETUPCONSTANT LOAD BYPASS DAMPER INSTALLATION AND SETUP
1. Start with the HVAC system’s Total CFM (3 ton @ 1200Cfm) 2 zone system (Zone 1 = 700cfm, Zone 2 = 500cfm).
2. Deduct the cfm for the smallest zone that can demand air by itself (500cfm).
3. Deduct damper stop leakage, if applicable (20% per ACCA Manual Zr) on the largest zone (700cfm x .20 = 140cfm) Total = 140cfm.
4. Deduct the cfm for any non-dampered (open) duct runs if applicable. ie. Bathrooms, Washer/Dryer area, etc. (2 x 60cfm = 120 cfm).
5. Do the math... (1200 - 500 - 140 - 120 = 440 cfm bypass flow).
6. The remaining cfm is the bypass cfm! Refer to the Bypass CFM chart and match the bypass cfm to the correct size CLBD bypass damper.
EXAMPLE: 3 ton system @ 400 cfm per ton = 1200 cfm 1200 cfm
Subtract Smallest Zone 2 cfm = 500 cfm - 500 cfm
Subtract Damper Stop Leakage = 140 cfm - 140 cfm
Subtract Open Runs = 120 cfm - 120 cfm
= 440 cfm - Bypass Flow
- 400 cfm - 8” CLBD
Residual = 40 cfm*
* A smaller bypass is always best. Resist the urge to size up. The 8” bypass (400 cfm) will result in 40cfm of residual air volume. A mere
3.3% (.033) of the total system airflow. This 40 cfm will become “overblow” into the active zone. Thus, when Zone 2 is the only active
zone, it will receive 540cfm rather than 500cfm.
** This example assumes single stage HVAC equipment or, Y2 is allowed to activate when the smallest zone calls.