SHI System Maintenance & Troubleshooting 2

Question 1

A solar thermal system shows a significant drop in flow rate over time. Which component is most likely causing this restriction?

Accepted Answer

Scale buildup in heat exchanger

Answer

Mineral scale deposits inside the heat exchanger restrict flow over time, especially in hard-water areas.

Question 2

When inspecting a solar collector during a maintenance visit, you notice the glazing has turned yellowish and opaque. What is the most appropriate corrective action?

Accepted Answer

Replace the glazing material

Answer

Yellowed, opaque glazing indicates UV degradation and loss of transmittance, requiring replacement to restore system efficiency.

Question 3

A differential temperature controller is cycling the pump on and off every few seconds. Which condition is the most likely cause?

Accepted Answer

The on/off differential is set too narrow

Answer

A very narrow differential between on and off set points causes rapid cycling; widening the differential stabilizes pump operation.

Question 4

During a pressure test of a closed-loop solar system, pressure drops steadily over 30 minutes with no visible leaks. Where should you check next?

Accepted Answer

Expansion tank bladder or diaphragm

Answer

A failed expansion tank bladder or diaphragm allows fluid to fill the tank completely, causing pressure loss without an external leak.

Question 5

What is the purpose of performing a glycol concentration check during annual maintenance of a drainback-type solar system?

Accepted Answer

Some drainback systems use dilute glycol; concentration affects freeze protection

Answer

While many drainback systems use water only, some use dilute glycol solutions, and annual concentration checks ensure adequate freeze protection.

(SHI) Solar Heating Installer Certification Practice Test

(SHI) Solar Heating Installer Certification Practice Test

SHI System Maintenance & Troubleshooting 2