Install Instructions

4
Heat Exchanger
When the application is configured for heat exchanger, the auxiliary relay is used to operate a pump that provides flow from
the heat exchanger to the storage tank. A heat exchanger may be included to isolate the fluid in the storage tank from the
fluid in the collector. In this application configuration, the auxiliary relay operates in parallel with the collector pump.
When configured for heat exchanger and delta T operation is required, the control turns on the auxiliary relay and operates
the collector pump accordingly.
Collector Sink (single tank operation)
When the application is configured for collector sink with a single storage tank, the auxiliary relay is used to operate a
device such as a mixing valve actuator that can divert flow from the collector to an auxiliary heat sink in the event the
storage tank reaches the tank limit temperature and the collector reaches the collector maximum temperature. The heat
sink acts as a mechanism to absorb heat, thereby preventing the collector from being compromised.
If the storage tank reaches the tank limit temperature during collector maximum operation the control then adjusts the
collector pump to full speed and turns on the auxiliary relay operating the diverting valve to direct flow from the collector
to an auxiliary heat sink. The auxiliary relay then remains on along with the collector pump at full speed until either the
collector temperature falls to 220°F, the storage tank temperature falls to 190°F, or a limit input is received. However, a
limit input will only cease operation between the collector and the auxiliary heat sink. Operation can still occur between the
collector and storage tank regardless of the limit input.
Collector Sink (double tank operation)
When the application is configured for collector sink with two storage tanks, the control uses the collector maximum feature
to provide collector sink operation with each tank being independent from one another. The control uses the collector pump
to provide collector maximum operation to the primary storage tank while the collector pump and auxiliary relay are used to
provide collector maximum operation to the second storage tank. The 00-VT provides priority for the primary storage tank
over the second storage tank. Note: an additional tank sensor is required (Taco part number 9300-2044).
If the control is operating between the collector and a storage tank and the storage tank rises to the maximum tank setpoint
temperature, and delta T operation is required for the other storage tank, the control switches to provide operation to the
other storage tank. If then that other storage tank reaches the tank maximum setpoint temperature, the control operates
to provide collector maximum operation. Once that storage tank reaches the tank limit temperature, the control switches
to provide collector maximum operation for the storage tank which first required operation. If the control is operating to
provide collector maximum operation for a storage tank, the collector pump and, if applicable, auxiliary relay remain on
until either the collector temperature falls to 220°F, the operating storage tank temperature falls to 190°F or a limit input
is received. If the control is operating to provide collector maximum operation for the non-priority storage tank, operation
terminates for the non-priority storage tank and switches to the priority storage tank if the primary storage tank requires
operation.
If the control is operating between the collector and a storage tank and the storage tank rises to the maximum tank setpoint
temperature, and delta T operation is not required for the other storage tank, the control operates to provide collector
maximum operation for the storage tank first requiring operation.
Tank Supplement
When the application is configured for tank supplement, the auxiliary relay is used to operate a device that supplements
the storage tank. This device includes a heat source such as an instantaneous water heater, boiler, heat pump or other
alternate heat source. The control operates the supplemental heat source to maintain the storage tank at 130°F. The
operation of the collector is independent of the operation of supplemental heat source.
When configured for tank supplement operation and the storage tank temperature drops to 130°F, the control turns on
the auxiliary relay. The auxiliary relay then remains on until either the storage tank temperature rises to 135°F or until
a limit input is received.
Booster Pump
When the application is configured for booster pump, the auxiliary relay is used to operate a high head pump in a drainback
application. In a drainback system, a booster pump is typically used to provide the necessary lift to meet the head
requirements on startup.
When configured for booster pump and delta T operation is required, the control adjusts the collector pump to full speed
and turns on the booster pump for 3 minutes. After the 3 minute period elapses, the control turns off the booster pump and
adjusts the collector pump to maintain the target temperature difference.
Holiday Feature
The control includes a holiday feature that allows for the primary storage tank to expel heat out the collector in the event the storage
tank is not being utilized such as vacation. In the event the storage tank is not being used it will be less capable of storing excess heat
from the collector resulting in potential frequent cycles when the collector temperature increases. To reduce the potential for this type
of operation to occur, the control operates to expel the heat from the storage tank to the collector resulting in a temperature drop from
the storage tank. This will then allow for longer periods of operation when the collector temperature increases.