Repair Techniques Flashcards

When replacing a gas valve on a commercial range, what must be verified after installation before returning the unit to service?

Answer: Leak test all connections with approved soap solution and verify proper outlet pressure

After replacing a gas valve, all connections must be leak-tested and outlet pressure verified to ensure safe, correct operation.

A commercial convection oven's blower motor runs but the fan blade does not spin. What is the most likely cause?

Answer: Sheared motor shaft key or set screw

If the motor runs but the blade does not spin, a sheared key or loose set screw has disconnected the blade from the shaft.

Which technique is used to identify a cracked heat exchanger in a commercial gas fryer?

Answer: Pressurize the heat exchanger with nitrogen and check for bubbles in the oil

Pressurizing the heat exchanger with nitrogen and submerging or coating with soap solution reveals cracks through bubble formation.

When soldering refrigerant tubing on a commercial ice machine, which gas should be flowed through the tubing to prevent internal oxidation?

Answer: Dry nitrogen

Flowing dry nitrogen through refrigerant tubing during soldering prevents copper oxide scale formation inside the lines.

A steam kettle is producing insufficient steam pressure. After confirming adequate water supply, what is the next diagnostic step?

Answer: Check and clean the steam generator scale buildup and inspect the safety valve

Scale buildup in the steam generator reduces heat transfer efficiency, and a faulty safety valve can bleed off pressure before it builds properly.

What is the correct procedure for re-torquing cylinder head bolts on a commercial food equipment compressor after initial repair?

Answer: Torque cold in a star pattern to spec, then recheck after first thermal cycle

Cylinder head bolts should be torqued cold in a star pattern per spec, then re-torqued after the first heat cycle to compensate for material relaxation.

A technician finds a commercial dishwasher wash arm delivering uneven spray. After clearing visible debris, the problem persists. What should be checked next?

Answer: Wash arm bearing or pivot wear causing misalignment

Worn wash arm bearings or pivot seats allow the arm to wobble or sit off-center, causing uneven spray even when ports are clear.