CRD Geothermal System Controls, Electrical & Auxiliary Components 3

Question 1

What control function does a 'desuperheater priority' mode provide in an advanced geothermal heat pump controller?

Accepted Answer

It allows the heat pump to run specifically to satisfy domestic hot water demand when the storage tank temperature drops

Answer

It gives space heating priority over domestic hot water generation at all times

Answer

It prevents the desuperheater from operating during the cooling season

Answer

It forces the water heater element to fully heat the tank without any heat pump input

Question 2

When two or more geothermal heat pumps serve a single residence, which control strategy best equalizes wear and extends equipment life?

Accepted Answer

Lead-lag sequencing with automatic runtime hour balancing between units

Answer

Always run the same unit as the lead and use the second only as emergency backup

Answer

Run all units simultaneously at all times regardless of load

Answer

Alternate units on a fixed 24-hour time-of-day schedule

Question 3

Why should large nighttime temperature setbacks be used cautiously with geothermal heat pump systems?

Accepted Answer

A large setback recovery may activate auxiliary resistance heat, eliminating the efficiency advantage of the heat pump

Answer

They cause the ground loop to freeze during the recovery period

Answer

They void the manufacturer warranty on the compressor

Answer

They cause excessive refrigerant migration during the off period

Question 4

What control feature monitors entering water temperature (EWT) to the heat pump and protects the unit when loop temperatures fall outside safe operating limits?

Accepted Answer

Loop temperature protection or low-EWT lockout control

Answer

High-pressure refrigerant cutout switch

Answer

Freeze protection thermostat on the domestic hot water line

Answer

Outdoor ambient temperature reset sensor

Question 5

In a geothermal system with multiple conditioned zones, what device mechanically controls conditioned airflow to each individual zone?

Accepted Answer

Motorized zone dampers controlled by a zone control board

Answer

Variable speed ground loop pump with zone-matched flow rates

Answer

A separate heat pump compressor dedicated to each zone

Answer

Bypass valves in the ground loop that divert flow by zone

Question 6

What advantage does an electronic expansion valve (EEV) provide over a fixed orifice or thermostatic expansion valve (TXV) in a geothermal heat pump?

Accepted Answer

It precisely modulates refrigerant flow in real time based on system conditions, improving efficiency across a wider operating range

Answer

It eliminates the need for refrigerant in the system

Answer

It expands the entering ground loop fluid before it contacts the heat exchanger

Answer

It regulates electrical voltage supplied to the compressor motor

Question 7

Which monitoring system capability allows a geothermal contractor to diagnose operational faults and review performance data without an on-site visit?

Accepted Answer

Web-connected smart thermostat or building automation system with geothermal-compatible remote access

Answer

Pneumatic control system with local gauge readouts

Answer

Standard analog thermostat with a paper log attached for homeowner use

Answer

Manual weekly inspection logs completed by the homeowner