CRD Geothermal System Controls, Electrical & Auxiliary Components

Question 1

Which type of thermostat is most recommended for geothermal heat pump systems to prevent unnecessary auxiliary heat activation?

Accepted Answer

Two-stage thermostat with intelligent recovery

Answer

Single-stage manual thermostat

Answer

Standard programmable thermostat without staging

Answer

Outdoor temperature-only reset thermostat

Question 2

What is the primary function of a desuperheater in a residential geothermal heat pump system?

Accepted Answer

Pre-heat domestic hot water using waste heat from the refrigerant cycle

Answer

Remove excess heat from the compressor housing

Answer

Regulate entering water temperature in the ground loop

Answer

Reduce electrical consumption during utility peak demand periods

Question 3

In a geothermal heat pump system, what does an auxiliary heat 'lockout' control primarily accomplish?

Accepted Answer

Prevents backup resistance heat from activating when the heat pump can adequately handle the load

Answer

Prevents the heat pump from running when outdoor temperatures exceed 65°F

Answer

Locks out the ground loop pump when loop temperatures are too high

Answer

Prevents the system from operating during utility demand response events

Question 4

What is the purpose of a flow center in a geothermal ground loop system?

Accepted Answer

To house the circulating pumps and provide a service/purging point for the ground loop

Answer

To control refrigerant flow rate inside the heat pump

Answer

To distribute conditioned air evenly through the duct system

Answer

To monitor and log electrical power consumption of the system

Question 5

Which control strategy improves geothermal heat pump efficiency by varying compressor output to match the actual heating or cooling load?

Accepted Answer

Variable capacity or variable speed compressor control

Answer

Two-position on/off compressor control

Answer

Time-of-day scheduling with fixed capacity

Answer

Outdoor air reset of leaving water temperature

Question 6

What voltage supply is most commonly used for residential geothermal heat pump compressors in the United States?

Accepted Answer

208/230V single-phase

Answer

120V single-phase

Answer

277V single-phase

Answer

480V three-phase

Question 7

What is the primary benefit of adding a buffer tank (or hydraulic separator) to a hydronic geothermal heat pump system?

Accepted Answer

It adds thermal mass to prevent short cycling of the heat pump compressor

Answer

It stores excess ground loop antifreeze for seasonal use

Answer

It filters sediment and contaminants from the loop fluid

Answer

It balances electrical load across the three phases of service