EPA 609 MVAC System Components & Operation 2

Question 1

What does a typical MVAC manifold gauge set measure?

Accepted Answer

Both high-side and low-side pressures simultaneously

Answer

Only high-side pressure

Answer

Only low-side pressure

Answer

Refrigerant purity and moisture content

Question 2

What is a typical low-side pressure reading for a properly charged R-134a MVAC system at idle?

Accepted Answer

25–45 psi

Answer

0–5 psi

Answer

100–150 psi

Answer

200–250 psi

Question 3

What is a typical high-side pressure reading for a properly charged R-134a MVAC system?

Accepted Answer

150–250 psi

Answer

25–45 psi

Answer

50–100 psi

Answer

400–500 psi

Question 4

What causes abnormally HIGH low-side pressure and HIGH high-side pressure in an MVAC system?

Accepted Answer

Overcharge or condenser cooling failure

Answer

Refrigerant undercharge

Answer

Restriction in the high-side liquid line

Answer

Compressor clutch slipping

Question 5

Which service port connects to the LOW side of an MVAC system?

Accepted Answer

The larger port (typically near the compressor inlet/accumulator)

Answer

The smaller port on the high side near the compressor outlet

Answer

Either port — they are interchangeable

Answer

The port on the condenser outlet

Question 6

A sight glass showing bubbles in an R-134a system indicates:

Accepted Answer

The system may be low on refrigerant

Answer

The system is fully charged and operating normally

Answer

The system is overcharged

Answer

The compressor is failing