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Twin-SANCO2 Additional Setup Information

Required Unit Spacing and Orientation

Heat Pumps should be located such that the air exhausted from one heat pump is not pulled in by the other (see below).

Electrical Requirements:

Provide a subpanel within reach of the twin-HPWH units in accordance to NEC and local codes

Power Supply:240V-1Ph-60Hz
Main Breaker Size:30 A
Breaker Size for each SANCO2 unit15 A

Functional Description

This setup enables the twin heat pumps to function as if there was only one heat pump, but with twice the capacity of a normal HPWH unit.

  • The two heat pumps are plumbed in parallel.
  • A common 3⁄4” cold supply pipe will run from the pod to a tee with 1⁄2” connections to each heat pump.
  • On the hot return, each heat pump plumbs 1⁄2” lines to a combining tee with a 3⁄4” outlet routed to the hot port of the tank.
  • Additionally, the heat pumps are wired to always run at the same time.

The Harvest Thermal Pod directly controls one heat pump — the primary heat pump — while the second heat pump is controlled by a current sensing switch. This current sensing switch is located only on the power line of primary heat pump, and switches on (turning on SANCO2 - 2) after a minimum amount of current flows to primary heat pump

The thermistor connection to primary heat pump will be typical of a Harvest Thermal single heat pump system, and the secondary heat pump will have a simple resistor installed on its thermistor connection that matches the resistance of the thermistor measuring a “‘cold” tank temperature.