abacus_phonograph:
2- Airflow is not linear, and in your dampers I would expect to see a fairly narrow airflow control window. There are bery large gaps at the sides. Even on very tight fitting ones, you would notice if measuring flow, that you might be down to 15% of design flow at 30% damper opening, for example.
I think this is backwards, at about 10% open, one will get about 30% of the flow.
air flow is based on resistance or pressure drop. home dampers are full duct size. if you want tight control. make the dampers about 1/10th the duct area. of course no one does that, but just saying these things are no engineered, just fabricated.
EXCELENT suggestion. SLOOOOOW moving.
look at the heating cycle.
space gets cold.
thermostat responds
thermostat calls for heat
heater energizes.
heater starts to send fuel
fuel starts to warm heat exchanger
heat exchanger reaches temperature
heat exchange temperature sensor energizes fan/pump
fan/pump begins to send heat out of heat exchanger
ducts begin to warm, residual cold air in the ducts is sent to the space
[take a note of steps that occur before the space actually sees any heat]
air in space begins to circulate
ducts warm, discharge air begins to increase in temperature
heater is still sending fuel, heat exchanger is still creating heat
warm air begins to increase room temperature
[ commercial thermostats will have anticipation cycle and send off signal before room is warm ]
temperature sensor will see increase in room air temperature
control will call for heater to stop fuel flow
[take a note of when typical control would try to end the call for heat ]
heat exchanger temperature control [independent control] will continue to call for fan to cool heat exchanger
hot air into space will continue to flow.
space will continue to increase in temperature
heat exchanger control will sense temperature below setting and turn off fan.
consider that most heating cycles are less than 15 minutes
call for heat, heater gets hot, space warms, heat stops sending heat
consider that humans do not mind temperature swings of 1-2 degrees. our duty cycle is quite long !
tips.
slow control of dampers. the reason one room is warm or cold compared to another is typically going to be a long duration event such as the sun warming a room. the TV is on, the stove/oven is on, there are many people in the space, etc.
if you want to move out of the stone age that we live in, consider occupancy sensors.
reduce heat in un-occupied spaces and heat when they become occupied.
also, minimal air circulation between cycles to eliminate pockets of hot or cold air.