Installation Manual 5.1.2
42
12.0 System Sequence of Operation for Fully Variable V-star with Protostar Thermostat
The I/O flex 6126 controller with the Protostar touch screen thermostat or the ZS pro
thermostat will drive the v-star compressor fully variable from 40 HZ to 160 HZ.
The compressor speed will be referred to as percentage in this sequence. This
percentage is not the compressor total capacity percentage but the percentage the
system is being driven between minimuim (40 HZ) to Maximum (160 HZ).
For example 1% = 40 HZ, 50% = 100 HZ, and 100% = 160 HZ.
A communicating thermostat (Protostar touch or ZS pro) is required to constantly report
the space temperature back to the controller for accurate variable speed control.
A priority DHW (Domestic Hot Water) or priority AHW (Auxiliary Hot Water) call is
determined by placing a temperature sensor on the hot water tank. This temperature is
read into the control board to determine DHW and AHW demand.
HEATING MODE
a. Protostar T-stat sensing space temp lower than heating set point.
i. Reversing valve de-energized.
ii. ECM Fan on at calculated speed equal to 400 CFM per calculated ton of V-star compressor.
ECM fan will run for one minute at this speed then slowly modulate to maintain 100 degree
discharge air temperature.
iii. Ground loop pump on.
iv. DHW pump on if hot gas temperature is hotter than DHW tank and DHW tank temp is lower
than DHW priority max temp set point.
v. V-star compressor will ramp up as needed to keep space temp within a half of degree of
heating set point.
b. Heating with Aux heat or Emergency Heat.
See section 11.1.12 for an explanation of the blower speed and damper operation when aux heat or e-
heat are calling.
i. Aux heat – If any zone has reached its zone limit for 30 minutes or longer and that zone is 1.5
degree below set point then the auxiliary strip heat will be allowed to start and heat with the
compressor.
ii. Aux heat with a fault – If the V-star compressor shuts down due to a limit trip or freeze
condition the auxiliary heat will be allowed to come on immediately. The Auxiliary heat will
cycle as needed via heating set point.
iii. E-heat mode – if the thermostat is set to E-heat. The compressor will be locked off and the
strip heat will cycle on and off as needed to provide heat for the space. This should only be
used during component failure scenario.
HEATING MODE WITH PRIORITY DHW CALL
a. In the event of a heating call and the DHW tank temperature drops below the Priority start temp set
point, the system will modulate as normal for heating except the minimum the compressor will be
allowed to run increases to 50%. The blower will maintain a calculated speed to achieve 100ºF
discharge air temp. The blower speed will not exceed the Zone limit calculated speed per zone.
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