Control for air handler

Abstract

The present invention provides for a control for activating and deactivating heating, cooling and fan recirculate modes having an interval timer switchable between a timer on (TON) state and a timer off (TOFF) state, both the TON and TOFF state durations are variable according to comparisons between room temperature and a set point temperature of the control and the control activating the fan recirculate mode when the room temperature deviates from the set point temperature of the control. An interval spacer is provided to prevent back to back fan on states.

1 . An air conditioning system comprising:
 an air handler;   a circulating fan;   a control for activating and deactivating heating, cooling and fan recirculate modes, the control operatively coupled to the air handler and the fan for controlling the air handler and the fan, the control having an interval timer;   the interval timer switchable between a timer on (TON) state and a timer off (TOFF) state, both the TON and TOFF state durations are variable according to comparisons between room temperature and a set point temperature of the control; the control activating the fan recirculate mode when the following conditions are met:   a) the control is in fan recirculate mode;   b) heating and cooling of the air conditioning system are not active; and   c) the room temperature deviates from the set point temperature of the control.   
     
     
         2 . The air conditioning system of  claim 1 , further comprising an interval spacing mechanism, wherein:
 d) the room temperature is compared to the set point temperature in order to avoid back to back fan on states and to allow activation of the fan when the interval timer is in the TON state.   
     
     
         3 . The air conditioning system of  claim 2 , wherein the interval spacing comparison is made according to the following formula subsequent to a heating mode:
     T   s +0.3 ≧T   r   ≧T   s +0.1   
       where T s  is the set point temperature and T r  is the room temperature. 
     
     
         4 . The air conditioning system of  claim 2 , wherein the interval spacing comparison is made according to the following formula subsequent to a cooling mode:
     T   s −0.3 ≦T   r   ≦T   s −0.1
   
       where T s  is the set point temperature and T r  is the room temperature. 
     
     
         5 . The air conditioning system of  claim 2 , wherein the interval spacing comparison is made according to the following formula:
     ABS ( T   r   −T   s )<Value  C      
       where T s  is the set point temperature and T r  is the room temperature. 
     
     
         6 . The air conditioning system of  claim 2 , wherein the interval spacing comparison is made according to the following formula:
   CALLON/(CALLON+CALLOFF)< A %.   
     
     
         7 . The air conditioning system of  claim 2 , wherein the interval spacing comparison is made according to the following formula:
   CALLON/(CALLON+CALLOFF)< B %.   
     
     
         8 . The air conditioning system of  claim 2 , wherein the interval spacing comparison is made according to the following formula:
   LASTOFF>Value C.   
     
     
         9 . The air conditioning system of  claim 2 , wherein the interval timer is activated upon power-up of the control and following expiration of the TON state, the TOFF state is activated until expiration and the interval timer operates in a continuous loop with TON and TOFF states sequentially running one after the other and the interval timer being independent of the interval spacing mechanism. 
     
     
         10 . The air conditioning system of  claim 1 , wherein the interval timer TON duration is equal to a first value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a first scaling factor. 
     
     
         11 . . The air conditioning system of  claim 10 , wherein the first value is 10 minutes and the first scaling factor is 0.1. 
     
     
         12 . The air conditioning system of  claim 10 , wherein the interval timer TOFF duration is equal to a second value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a second scaling factor. 
     
     
         13 . The air conditioning system of  claim 12 , wherein the second value is 20 minutes and the second scaling factor is 0.2. 
     
     
         14 . The air conditioning system of the  claim 1 , wherein the control is a thermostat. 
     
     
         15 . The air conditioning system of  claim 14 , wherein the thermostat includes one of a mechanical fan switch for setting the fan to recirculate mode and a touchscreen input for setting the fan to recirculate mode. 
     
     
         16 . A method for activating a fan recirculate mode of an air conditioning system comprising the steps of:
 providing a control having an interval timer, the control operatively coupled to an air handler and a fan for activating and deactivating heating, cooling and fan recirculate modes;   powering the control in order to set the interval timer to a timer on (TON) state;   varying the duration of the TON state by the interval timer to a first value by comparing room temperature with a set point temperature of the control;   setting the interval timer to a timer off (TOFF) state;   varying the duration of the TOFF state of the interval timer to a second value by comparing the room temperature and the set point temperature of the control;   setting the control to fan recirculate mode;   monitoring the control to confirm no heating or cooling of the air conditioning system is active; and   activating the fan recirculate mode when the room temperature deviates from the set point temperature of the control.   
     
     
         17 . The fan activation method of  claim 16 , wherein the fan recirculate mode is activated when the interval timer is in TON state only after an interval spacing mechanism is executed by comparing the room temperature to the set point temperature of the control. 
     
     
         18 . The fan activation method of  claim 17 , wherein the interval spacing mechanism value is not preselectable. 
     
     
         19 . The fan activation method of  claim 17 , wherein the interval spacing mechanism operates according to the following formula subsequent to a heating mode:
     T   s +0.3 ≧T   r   ≧T   s +0.1   where T s  is the set point temperature and T r  is the room temperature.   
     
     
         20 . The fan activation method of  claim 17 , wherein the interval spacing mechanism operates according to the following formula subsequent to a cooling mode:
     T   s −0.3 ≦T   r   ≦T   s −0.1
   where T s  is the set point temperature and T r  is the room temperature.   
     
     
         21 . The fan activation method of  claim 16 , further comprising the step of setting the TON duration that is equal to a first value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a first scaling factor. 
     
     
         22 . The fan activation method of  claim 21 , wherein the first value is 10 minutes and the first scaling factor is 0.1. 
     
     
         23 . The fan activation method of  claim 21 , further comprising the step of setting the TOFF duration that is equal to a second value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a second scaling factor. 
     
     
         24 . The fan activation method of  claim 22 , wherein the second value is 20 minutes and the second scaling factor is 0.2. 
     
     
         25 . The fan activation method of  claim 22 , wherein the TOFF state is not dependent from an end of a last operation of the fan. 
     
     
         26 . The fan activation method of  claim 22 , wherein the first and second value and first and second scaling factors are not user selectable. 
     
     
         27 . The fan activation method of  claim 16 , further comprising the steps of:
 activating the interval timer upon power-up of the control;   activating the TON state until expiration;   activating the TOFF state until expiration; and   operating the interval timer in a continuous loop with TON and TOFF states sequentially running one after the other and the interval timer being independent of the interval spacing mechanism.   
     
     
         28 . The fan activation method of  claim 16 , wherein the control simultaneously processes the comparing, monitoring and activating steps. 
     
     
         29 . The fan activation method of  claim 16 , wherein the control includes a microprocessor for simultaneously processing the comparing, monitoring and activating steps. 
     
     
         30 . The fan activation method of  claim 16 , wherein the TON duration is between 5 and 15 minutes. 
     
     
         31 . The fan activation method of  claim 16 , wherein the TON duration is approximately 50% TOFF. 
     
     
         32 . The fan activation method of  claim 16 , wherein the interval timer TON and TOFF durations are not preselectable by a user. 
     
     
         33 . The fan activation method of  claim 16 ; wherein a fan auto mode and fan on mode are provided and further comprising the steps of monitoring the control to confirm no auto fan mode or fan on mode are active. 
     
     
         34 . The fan activation method of  claim 16 , wherein the air handler is a HVAC system, including an air filter assembly and air ducts for circulating indoor and outdoor air. 
     
     
         35 . The fan activation method of  claim 16  further comprising the steps of:
 depressing a fan button of the control; 
 selecting the recirculate mode by scrolling through multiple fan modes; and 
 upon selection of the fan recirculate mode providing an indication of the mode selected. 
 
     
     
         36 . The fan activation method of  claim 35 , wherein the control includes a display having an LCD display having touch sensitive areas including a touch button for the fan button. 
     
     
         37 . The fan activation method of  claim 36 , wherein the icon is an alpha numeric presented in a fan mode display area. 
     
     
         38 . The fan activation method of  claim 36 , wherein the icon is a graphical representation of a fan presented on the display. 
     
     
         39 . The fan activation method of  claim 35 , wherein the fan button is a mechanical switch. 
     
     
         40 . The fan activation method of  claim 16 , were in the activation of the fan occurs when a microcontroller of the control energizes a fan terminal in order to power the fan. 
     
     
         41 . A control for activating and deactivating heating, cooling and fan recirculate modes comprising:
 an interval timer switchable between a timer on (TON) state and a timer off (TOFF) state, both the TON and TOFF state durations are variable according to comparisons between room temperature and a set point temperature of the control and the control activating the fan recirculate mode when the room temperature deviates from the set point temperature of the control.   
     
     
         42 . The control of  claim 41 , further comprising an interval spacing mechanism, wherein the room temperature is compared to the set point temperature in order to avoid back to back fan on states and to allow activation of the fan when the interval timer is in the TON state. 
     
     
         43 . The control of  claim 42 , wherein the interval timer is activated upon power-up of the control and following expiration of the TON state, the TOFF state is activated until expiration and the interval timer operates in a continuous loop with TON and TOFF states sequentially running one after the other and the interval timer being independent of the interval spacing mechanism. 
     
     
         44 . The control of  claim 41 , wherein the interval timer TON duration is equal to a first value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a first scaling factor. 
     
     
         45 . The control of  claim 41 , wherein the interval timer TOFF duration is equal to a second value plus the absolute value of the difference between the set point temperature and the room temperature multiplied by a second scaling factor. 
     
     
         46 . A control for activating and deactivating heating, cooling and fan recirculate modes comprising:
 an interval timer switchable between a timer on (TON) state and a timer off (TOFF) state;   an interval spacer to prevent back to back fan on states;   the interval timer setting TON and TOFF state durations that are variable and are set independently from the operation of the interval spacer; and   the control activating the fan recirculate mode when the room temperature deviates from the set point temperature of the control following operation of the interval spacer.   
     
     
         47 . The control of  claim 46 , wherein the interval spacer operates according to the following formula:
     ABS ( T   r   −T   s )<Value  A      where T s  is the set point temperature and T r  is the room temperature.   
     
     
         48 . The control of  claim 46 , wherein the interval spacer operates according to the following formula:
   CALLON/(CALLON+CALLOFF)< A %.   
     
     
         49 . The control of  claim 46 , wherein the interval spacer operates according to the following formula:
   CALLON/(CALLON+CALLOFF)< B %.   
     
     
         50 . The control of  claim 46 , wherein the interval spacer operates according to the following formula:
   LASTOFF>Value A.   
     
     
         51 . The control of  claim 46 , wherein the interval spacer operates by comparing the room temperature to the set point temperature of the control to allow activation of the fan when the interval timer is in the TON state. 
     
     
         52 . The control of  claim 51 , wherein the interval spacer operates according to the following formula subsequent to a heating mode:
     T   s +0.3 ≧T   r   ≧T   s +0.1   where T s  is the set point temperature and T r  is the room temperature.   
     
     
         53 . The control of  claim 51  wherein the interval spacer operates according to the following formula subsequent to a cooling mode:
     T   s −0.3 ≦T   r   ≦T   s −0.1
 
 where T s  is the set point temperature and T r  is the room temperature.