Condensing Unit Hermetic Compressor - Stalling and Tripping??

[French Fox]

Hi Everyone,
Just looking at an Ice Cream Van with a small 1ph hermetic condensing unit (on R409A).
The customer tells me a capacitor exploded and he replaced it, but fridge not cold.

When I turn the unit on it starts ok and works for maybe a minute. Back Pressure falls Head pressure rises, all looks great, but then the compressor starts 'rumbling, and stalling' and after 10 - 15 secs, trips on the internal thermal overload.

The capacitor looks fine, is the same rating 80mf. The relay is wired correctly. But the compressor is too hot for the work done when it cuts out. I've tested the windings (cold) ad they check out more or less ok, they pretty much add up.

Any ideas???

Cheers guys.
FrenchFox.

[chemi-cool]

When I turn the unit on it starts ok and works for maybe a minute. Back Pressure falls Head pressure rises,

That's a good sign that you have a restriction somewhere in the unit. Have a good check up to find it.

[Magoo]

Check motor current, to make sure the relay is dropping out start winding after startup.

[French Fox]

Good advice thanks.

[mikeref]

80 uf is the start capacitor. There is a run capacitor to check as well.

[install monkey]

condenser coil, clean? fan working- wont be a weak klaxon, clip the running current, pot may be siezing