Had a weird fridge compressor hum that turned out to be a loose service valve cap

Was on a call for a fridge not cooling in a rental unit last week, and the noise was driving me nuts. I checked the usual stuff, but it was just a quarter-turn loose cap on the suction service valve causing the vibration. Anyone else run into a simple fix like that making all that racket?

3 comments

3 Comments

erickelly4d ago

Remember that service valves are meant to be back-seated during normal operation. A loose cap can absolutely cause that buzzing, but if the valve stem itself is cracked open even a little, you're losing refrigerant charge. Always check the stem position first before just tightening the cap. I've seen guys chase a low charge for an hour when the suction service valve was just cracked off the back seat.

henryt184d ago

Honestly that's such a good point. I've made that exact mistake before, just cranking down the cap when I heard the noise. Took me way too long to realize the stem was barely open. Ngl it feels like a basic thing but it's so easy to skip when you're in a hurry. Always gotta check the valve position first, saves so much time.

felixlane4d ago

Yeah this hits close to home honestly. I did the exact same thing on a roof last summer, spent a good 20 minutes messing with the cap and wondering why the pressure was still dropping. Felt like a total idiot when I finally remembered to check the stem and saw it was cracked open maybe a quarter turn. It's one of those things that seems so obvious after you figure it out but in the moment you just assume it's something else. Makes you appreciate how easy it is to overlook the simple stuff when you're rushing or tired. Glad I'm not the only one who learned this the hard way.