refrigeration Quiz

[paul_h]

Lame test for the beginners.
An internal unit with "flare" connections is pre-charged with nitrogen during manufacture.
I said false, they said:
Not correct
I happen to know none of the aircons I support have nitrogen in the evap. The test is wrong if they mean pressurised, as none of them have any pressure in them. If they mean 1atm of pressure so you can't tell when opening them up, then they've worded it badly.

LP faults usually cause frosting of the evaporator.
I ticked false, they said:
Not correct
what if there's no refrigerant in the system, how will the evap frost up then? What if there's a LP cut out, how will the sytem run long enough to frost up then?
They should have said LP faults sometimes may result in frosting or the evap.

[frank]

LP faults usually cause frosting of the evaporator.
I ticked false, they said:
Not correct
what if there's no refrigerant in the system, how will the evap frost up then? What if there's a LP cut out, how will the sytem run long enough to frost up then?
They should have said LP faults sometimes may result in frosting or the evap.

An LP fault usually causes a trip. An undercharge or loss of gas usually causes frosting of the evap.

[TXiceman]

An LP fault usually causes a trip. An undercharge or loss of gas usually causes frosting of the evap.

In addition to low charge, you have to first look air air flow over the evaporator. Low air flow, due to plugged filter, dirty coil or fan not operating at speed, will all show a low suction pressure and possibly a frosted coil.

Try to charge a system with a dirty coil and see what you get...

Ken