Bard Q24A1 Installationair conditioner Instructions Manual

Manual 2100-522BPage 34 of 38OPTIONAL CLIMATE CONTROLSSEQUENCE OF OPERATIONThe Climate Control Option A is an electronic, non-programmable manual or auto changeover thermostat.The thermostat may be manually set to heat or coolmode. The thermostat will maintain the temperature seton the thermostat in the mode in which it is set.The Climate Control Option D is an electronic,programmable thermostat. The thermostat can be set inthe heat, cool or automatic mode. When the thermostatis sent in the heat mode, it can heat only to maintain thetemperature set on the thermostat. When the thermostatis set in the cool mode, it can cool only to maintain thetemperature set on the thermostat. When the thermostatis set in the automatic mode, the thermostat can changeautomatically to the heat or cool modes to maintain thetemperature set on the thermostat.The Climate Control Option “H” is an electronic,programmable thermostat and a CO2 controller. Thethermostat can be set in the heat, cool or automaticmode. When the thermostat is set in the heat mode, itcan heat only to maintain the temperature set on thethermostat. When the thermostat is set in the coolmode, it can cool only to maintain the temperature seton the thermostat. When the thermostat is set in theautomatic mode, the thermostat can changeautomatically to the heat or cool modes to maintain thetemperature set on the thermostat.The CO2 controller will energize the vent option and theID blower when the room CO2 levels rise over set level.Default CO2 set point is 1000 ppm. See Figure 23.PRESSURE SERVICE PORTSHigh and low pressure service ports are installed on allunits so that the system operating pressures can beobserved. Pressure curves can be found later in themanual covering all models on both cooling and heatingcycles. It is imperative to match the correct pressurecurve to the unit by model number. Upper and lowerservice doors must be attached to obtain proper reading.SEQUENCE OF OPERATIONCooling – Circuit R-Y makes the thermostat pull in thecompressor contactor starting the compressor andoutdoor motor. The G (indoor motor) circuit isautomatically completed on any call for coolingoperation, or can be energized by manual fan switch onsubbase for constant air circulation.Heating – Circuit is completed for R-W1 on eachheating “on” cycle, energizing the electric heatcontactor. R-G also makes starting indoor blowermotor.Second stage heat – Energized circuit R-W2 and theelectric heat contactor for the second bank of heaters (ifequipped) is energized.High / Low Pressure control provides protection for thecompressor. In the advent system pressures go above600 PSI or below 15 PSI in cooling mode thecompressor will be stopped. This will activate the redlight located in the control panel. The lockout circuitwill hold compressor off line. When the systemproblem is corrected, the unit operation can be restoredby turning of the main power supply off and then backon, or reset the room thermostat. The low pressurecontrol has a bypass to eliminate nuisance lockout oncold start up. Factory set to 2 minutes.FIGURE 23CO2 CONTROLLER – FACTORY SET TO 1000PPM"SW1" SET TO ON "OUT" SET TO 20-100%"SW2" SET TO ONOFFONONOFF0-100%20-100%VOLTAGECURRENTSW2SW1OUT AN"AN" SET TO VOLTAGEMIS-2667