Bard Q-TEC Q24H1 Installation Instructions Manual

Bard Q-TEC Q24H1 Installation Instructions Manual Manual pdf 33 page image

Manual 2100-519CPage 33 of 42SEQUENCE OF OPERATIONCOOLING – Circuit R-Y makes at thermostat pulling incompressor 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 – A 24V solenoid coil on reversing valvecontrols heating cycle operation. Two thermostatoptions, one allowing “Auto” changeover from cycle tocycle and the other constantly energizing solenoid coilduring heating season, and thus eliminating pressureequalization noise except during defrost, are to be used.On “Auto” option a circuit is completed from R-W1 andR-Y on each heating “on” cycle, energizing reversingvalve solenoid and pulling in compressor contactorstarting compressor and outdoor motor. R-G also makestarting indoor blower motor. Heat pump heating cyclenow in operation. The second option has no “Auto”changeover position, but instead energizes the reversingvalve solenoid constantly whenever the system switch onsubbase is placed in “Heat” position, the “B” terminalbeing constantly energized from R. A Thermostatdemand for heat completes R-Y circuit, pulling incompressor contactor starting compressor and outdoormotor. R-G also make starting indoor blower motor.High / Low Pressure control provides protection for thecompressor. In the event system pressures go above 600PSI or below 15 PSI in either cooling or heating mode,the compressor will be stopped. This will activate thered light located in the control panel. The lockoutcircuit will 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.The bypass timer should be set to 120 seconds and thisis to assure there is no nuisance tripping of the low-pressure control during startup in heating mode undercold weather conditions. See Defrost Control Board -Figure 24.OPTIONAL 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 set 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."SW1" SET TO ON "OUT" SET TO 20-100%"SW2" SET TO ONOFFONONOFF0-100%20-100%VOLTAGECURRENTSW2SW1OUT AN"AN" SET TO VOLTAGEMIS-2667FIGURE 23CO2 CONTROLLER – FACTORY SET TO 1000PPM