pulley design

Tempstar 2-Stage Heat Pump T4H7

My unit is back up and running. Leak was located on the flare nut, as suspected, and all work was covered under his warranty. I now have 70psi on ...

HVAC two stage heat pump with variable condenser motor

More stuff in the junk pile! You don't see condensers with variable fan motors every day :)

HVAC Heat Pump Package Unit Restriction

Stage one of a two stage package heat pump, with a restriction, possible failed check valve.

U10050 Transparent Stirling Engine

in three different modes: as a heat engine, heat pump and refrigerating machine. The displacement cylinder and displacement piston are made of ...

Controlling Dual Fuel without an Outdoor Temperature Sensor

White Rodgers Heat Pump 90 Series thermostats  use a temperature control algorithm to determine the optimum time to activate the second stage or auxiliary heat.  The thermostat constantly monitors 1st stage performance and produces a time delay based on the result.  The time element of the delay (0-30 minutes) varies depending on the performance of the first stage.  As an example, in Heating, assume for the last 2 hours the thermostat is set on 70 В° of setpoint, the thermostat will delay second stage for a longer time if the room temperature quickly changes.  Once the second stage comes on, it will come on sooner the next time there is a difference between the setpoint and the room temperature.  The thermostat is constantly monitoring the performance of the system and the systems ability to keep the area within about 1 degree of setpoint so even raising the temperature in heating or lowering it in cooling will not always force the thermostat to bring the second stage on quickly.  The net effect of the staging program is when the first stage is capable of making temperature the second stage will delay longer.  When the thermostat calculates that first stage cannot make temperature in a reasonable time, the second stage will come on sooner.  This is a built in function that automatically optimizes the use of additional stages of heat or cool.  A thermostat on a Dual Fuel system uses a staging algorithm like the one described above and also turns off the compressor(s) when the furnace is energized.

White Rodgers Heat Pump 90 Series thermostats  use a temperature control algorithm to determine the optimum time to activate the second stage or auxiliary heat.  The thermostat constantly monitors 1st stage performance and produces a time delay based on the result.  The time element of the delay (0-30 minutes) varies depending on the performance of the first stage.  As an example, in...

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