1. Technician’s Guide and Workbook for Zoning Section 7: Zone Damper System Design

2. Mandatory Design Requirements
PROTECTING THE CENTRAL HEATING and COOLING SYSTEM IS A PRIMARY REQUIREMENT!

3. Space Humidity Control
30% to 60%

4. Quiet Damper Actuation
Damper Actuator

5. No Drafts or Stagnant Air (Caused By Zone Dampers)

6. Range of System
Range of HVAC system must work for all components in all phases of operation.
Airflow across the heat exchanger must always be maintained, and zones must
be designed with excess air escape plans!

7. Zone Temperature Swing
Range of HVAC system must work for all components in all phases of operation.
90oF
70oF
72oF VS
60oF

8. Simultaneous Heating and Cooling
Should be avoided in the design if possible. When required the 1st recommendation is use auxiliary equipment. The second (if the above is not possible) is use a polling control scheme.

9. Zone Priority & Temperature Swing
High Priority Areas:
Occupied Areas
Time of Day
Low Priority Can Be used for:
Dump zones
Overblow

10. Developing A Zoning Plan (Zoning the Long Residence from Manual J8)
Make a Survey: Get or draw the Plans!
Get owner expectations.
Produce preliminary plan using loads and duct design.
Determine room CFM design requirements using Manual D room heating CFM and cooling CFM.
Select supply and return outlets and locations.

11. Developing A Zoning Plan (Long Residence Update)
Balancing CFM =
136 CFM cooling and 105 CFM Heating

12. Long Residence 1st Floor Plan Zone 1

13. Long Residence 1st Floor Plan Zone 2

14. Long Residence Basement Plan Zone 3

15. Zone 1 Long Residence Diffuser CFM H/C

16. Zone 2 Long Residence Diffuser CFM H/C

17. Zone 3 Long Residence Diffuser CFM H/C

18. Equipment Capacity CFM???
1,000 CFM ,002 CFM
40,452 BTUH 16,709 BTUH

19. XYZ Gas Furnace BTUH and CFM
Gas Furnace 60,000 input Btuh = 57,000 Btuh output at 1,000 CFM.
57,000 ÷ 40,452 × 100 = 141%
With AC: Manual S
preferred 140%
allowed 200% OK on heating side!

20. XYZ Gas Furnace 1,000 CFM & 1.5 ton AC
Expanded AC data at design conditions BTUH Sensible = 15,000 BTUH Latent = 2,800 BTUH Total = 17,800 Cooling Load BTUH = 16,709 17,800 ÷ 16,709 × 100 = 107% Manual S allows for 115% so we are OK

21. XYZ External Static Pressure Chart
For calculating the final CFM for field balancing numbers measure the OEM ESP and Interpolate the CFM value based on fan motor speed.

22. XYZ External Static Pressure Chart 1
Fan Speed Low ESP = 0.4 What is the CFM?
812 CFM

23. XYZ External Static Pressure Chart 2
Fan Speed Medium Low ESP = 0.3 What is the CFM?
1,015 CFM

24. XYZ External Static Pressure Chart 3
Fan Speed Medium High ESP = 0.35 What is the CFM?
(1, ,089) ÷ 2 = CFM

25. Field Notes
The homeowner’s callback stated the new zone system was noisy in the bedroom and they could not sleep. The Technician measured the system airflow and found it was higher than design. The OEM chart was checked and the fan speed was lowered. The bedroom zone damper was then opened and reset for the design airflow. The homeowner was satisfied with the lower sound levels in the bedrooms.