Install Instructions

3
Manual Operation
The 00-VT includes a manual override feature that turns on all outputs including the collector pump at full speed for up to a 24 hour
period. The manual override feature is activated by creating an open circuit with both the source sensor and the tank sensor after both
sensors have been installed without an error condition. Once activated, the manual override remains in effect until either the source
sensor or tank sensor is connected without an error condition, or 24 hours elapses from the time the manual override is activated.
Mixing Operation
The 00-VT operates the collector pump to transfer heat between the collector and a storage tank based on a setpoint temperature
difference (delta T) and setpoint temperature diference differential. The setpoint temperature difference is fixed at 10°F and the
setpoint temperature difference differential is fixed at 5°F.
For delta T operation, the collector pump operates between the minimum variable speed output and full speed. Once the actual
temperature difference rises to at least 10°F, the collector pump turns on at full speed for 10 seconds. After 10 seconds, the collector
pump operates to maintain the 10°F setpoint target temperature difference. As the actual temperature difference increases, the
variable speed output is increased. As the actual temperature difference decreases, the variable speed output is decreased. Once
the actual temperature difference falls to the 5°F setpoint target temperature difference differential, the collector pump is turned off.
The 00-VT allows for operation with a single storage or two storage tanks. With a single storage tank, the control uses the collector
pump to provide delta T operation between the collector and the primary storage tank. The auxiliary relay can then be configured for
heat exchanger, collector sink, tank supplement or booster pump operation. With two storage tanks, the control uses the collector
pump and auxiliary relay together to provide delta T operation between the collector and the second storage tank. With two storage
tanks, the application configuration must be assigned to collector sink.
When configured for two storage tanks, operation for the primary storage tank is independent from the second storage tank. Delta T
operation occurs first for the storage which requires it. However, the primary storage tank has priority over the second storage tank.
In this case, if the control is providing delta T operation for the second storage tank and delta T operation is required for the primary
storage tank, the control will turn off the auxiliary relay and use only the collector pump to provide operation for the primary storage
tank. This could be typical of an application where the primary storage tank is the Domestic Hot Water (DHW) tank.
Minimum Variable Speed Output
The 00-VT includes a minimum variable speed output for the collector pump during delta T operation in which
the variable speed output is adjusted between 30% output and full output.
Tank Maximum Operation
The 00-VT includes a tank maximum feature that conditionally ceases operation if the storage tank reaches
the maximum tank setpoint temperature. If during delta T operation the tank temperature rises to the maximum
tank setpoint temperature, the control turns off the collector pump and, if applicable, the auxiliary relay. The
collector pump and, if applicable, auxiliary relay then remain off until the tank temperature falls to the maximum
tank setpoint temperature less the maximum tank setpoint temperature of 5°F. The maximum tank setpoint
temperature is set using the dial. Subsequent operation is dependent on the application configuration and the
other control features.
Tank Limit Operation
The 00-VT includes a tank limit feature that ceases operation if the storage tank reaches its upper limit during collector maximum
operation. This scenario could occur if operation first ceases during delta T operation when the storage tank reaches the maximum tank
setpoint temperature resulting in potential collector stagnation conditions. Collector Maximum operation would then occur in an attempt
to cool the collector while further heating the storage tank to its upper limit. If during collector maximum operation the tank temperature
rises to the tank limit temperature of 200°F, the control turns off the collector pump and, if applicable, the auxiliary relay. The collector
pump and, if applicable, auxiliary relay then remain off until the tank temperature falls to 190°F. The tank limit operation is not available
when the control is configured for drainback.
Collector Maximum Operation
The 00-VT includes a collector maximum feature that operates the collector pump, and if applicable, the auxiliary relay to transfer
heat from the collector to the storage tank in the event the collector becomes too hot due to stagnation conditions. This scenario
could occur if the tank maximum operation ceases delta operation causing the collector to stagnate and become too hot. If the tank
temperature is at least the tank maximum temperature and the collector temperature rises to collector maximum temperature of
230°F, the control turns on the collector pump and, if applicable, the auxiliary relay to further heat the storage tank. The collector
pump and, if applicable, auxiliary relay then remain on until either the collector temperature falls to 220°F or the tank temperature
rises to the tank limit temperature of 200°F. The collector maximum operation is not available when then control is configured for
drainback.
Collector Limit Operation
The 00-VT includes a collector limit feature that turns off all outputs if the collector temperature reaches its upper limit in an attempt to
protect the solar system components. In the event the collector pump and, if applicable, auxiliary relay are operating and the collector
temperature rises to the collector limit temperature of 250°F, the control turns off all outputs. All outputs then remain off until the
collector temperature falls to 240°F. The collector limit operation is not available when then control is configured for drainback.
Drainback (DIP Switch 3)
The 00-VT supports a drainback feature. In a drainback system, the control turns off the collector pump when operation
is no longer required. Once the collector pump turns off, the fluid in the collector and distribution piping drains back into
reservoir. Once operation is required, the fluid in the tank must be circulated through the collector and throughout the
distribution. In order to ensure that the fluid is properly circulated throughout the solar system with all the air purged out,
the collector pump operates at full speed for a 3 minute period when operation is required. After the 3 minute period, the
00-VT operates the collector pump based on the variable speed injection requirements.