If Fan Switch on 4 zone controller is set to ON instead of Auto, then system fan will run continuously. Any time Comfort Zone is operating fan, it will be in active control of system.
NOTE: If Auto Fan Off For Heating option (rotary switch position T-9) is ON, and Fan Switch on the 4 zone controller is ON, Comfort Zone will operate fan full time.
Operating fan continuously will place Comfort Zone in a Float Mode any time no active heating or cooling is taking place. During Float Mode, Comfort Zone will position zone dampers based upon demand in each zone. Comfort Zone will check air temperature in duct work and allow air into zones if it will help zones reduce their individual demands. For example, if temperature of air in duct work is 65°F, cooling comfort setpoint for a zone is 72°F, and space temperature is 73°F, then Comfort Zone will open damper servicing that zone and allow cooler air into space.
Ventilation Mode is only in effect when temperature of supply air is between 65°F and 80°F. Ventilation Mode establishes minimum position of zone dampers and is intended to help air movement throughout zones and reduce chance of having areas which are stagnant or have high humidities with respect to rest of system. The changes to dampers are detailed in the next section "Control- ling the Zone Dampers."
CONTROLLING THE ZONE DAMPERS
The zone dampers have a total of 16 possible positions or increments which are numbered 0 (zero) through 15. Position number 0 is fully closed and position number 15 is fully open. While damper servicing reference zone remains fully open, all other zone dampers are positioned by selecting a position equal to demand of space in tenths of a degree. (See Table 2.)
Table 2ÐZone Damper Positions
Damper Position Versus Zone Demand
| DAMPER | DEMAND °F | DEMAND °C |
| POSITION |
| | |
| 0 | 0 | 0 |
| Fully Closed |
| | |
| 1 | 0.1 | 0.06 |
| 2 | 0.2 | 0.11 |
| 3 | 0.3 | 0.17 |
| 4 | 0.4 | 0.22 |
| 5 | 0.5 | 0.28 |
| 6 | 0.6 | 0.33 |
| 7 | 0.7 | 0.39 |
| 8 | 0.8 | 0.44 |
| 9 | 0.9 | 0.50 |
| 10 | 1.0 | 0.55 |
| 11 | 1.1 | 0.61 |
| 12 | 1.2 | 0.67 |
| 13 | 1.3 | 0.72 |
| 14 | 1.4 | 0.78 |
| 15 | 1.5 | 0.83 |
| Fully Opened |
| | |
For example, a zone which has a 1.0°F demand will have damper set to position number 10 while a zone which has a demand of 0.5°F will have damper set to position number 5. A demand of 0 (zero) will fully close zone damper. Any zone which has a demand greater than 1.5°F will remain fully open.
Notice that positions are based upon tenths of a degree Fahrenheit. If Comfort Zone has Celsius Temperature Display option (rotary position T-2) turned on, the damper control is still based upon Fahrenheit scale.
The damper positions in table are also used during a Float Mode. A zone with a demand of 0.5°F will be set to position number 5.
The actual control of zone dampers by Comfort Zone system can be modified using 3 configurable options. These are Maximum Damper Position, Minimum Damper Position, and Ventilation Mode.
These options apply to all zone dampers simultaneously. Any dampers servicing Zone 1 cannot be configured differently than those servicing Zone 2. The options are as follows:
1.The Maximum Damper Position (rotary position number S-4) sets maximum open damper position for all 4 zones. The allowable range for this option is damper positions number 8 through number 15 (fully open). The factory default is 15. The only time zone dampers will exceed this position is if system fan is off or zone dampers are being calibrated.
2.The Minimum Damper Position (rotary position number S-5) sets minimum open damper position for all 4 zones. The allowable range for this option is damper positions number 0 through number 7. The factory default is number 0 (fully closed). If Ventilation Mode (rotary position T-25) is turned OFF, then minimum damper position will be an absolute minimum regardless of operating mode. If Ventilation Mode is turned ON, then minimum damper position will be mini- mum position during a Ventilation Mode only and dampers will be allowed to fully close at any other time.
3.Ventilation Mode (rotary position T-25). If Ventilation Mode is turned ON, then any time air inside supply air duct work is between 65°F and 80°F, system will be in a "Ventilation Mode". During a Ventilation Mode all zone dampers will have a minimum position which is set by Minimum Damper Position (rotary position S-5). The zone dampers are not allowed to fully close as long as supply air temperature remains within the 65°F-80°F range. If supply air temperature falls outside the 65°F-80°F range, then zone dampers may fully close.
NOTE: If Ventilation Mode option (rotary position T-25) is turned ON, and Minimum Damper Position (rotary position S-5) is set to position 0, there is no difference between Float Mode and Ventilation Mode. In other words, Ventilation Mode option has no effect on system.
OPERATING THE HEATING AND COOLING EQUIPMENT
Before any heating or cooling equipment is started, Comfort Zone must first choose between heating or cooling. For most of the year there is little question as to the need for heat or cooling. But for portions of the year, particularly during mid-season, a building may have simultaneous needs for both heating and cooling.
The first step in selecting heating or cooling is the determination of a Reference Zone. If there is a single zone which has greatest demand, then it will become the Reference Zone and Comfort Zone will start equipment based upon needs of that zone. If 2 zones have same "greatest demand" but in different modes (1 needs heating and the other needs cooling), then Comfort Zone will select mode which has greatest number of zones which require same mode.
CONTROL STRATEGY FOR HEATING / COOLING STAGES
The Comfort Zone system will attempt to minimize use of additional stages of heating or cooling equipment. In an ideal case, building conditioning needs can be supplied by first stage cooling or first stage heating alone.
For most heat pump applications, there may be only 2 or 3 stages of heat depending upon type of emergency heater present. For a heat pump, secondary heat source will generally be an electric strip
