thermo king ts 500 help rerquired

[stormycgc]

hello there im a carrier engineer having troubles on a tk ts500
it cools no problem to about -8 then goes into null
i have reclaimed gas vac and recharged the systym with correct weight of r404a check the air switch and the presures when running are 27 psi and 220 psi on the high side
the sight glass if full and i have a 6 degrees across the coil in cooling
any one have any other ideas ???
cheers

[cadwaladr]

what is its history, any alarms/codes showing

[SKOOBY]

If it is maintaining six degrees diff
over coil
Check body insulation door seals etc

[abbsnowman]

Whats the ambiant? I say 8 degrees should be min. delta.
I have found that the TK's like a condenser bath once in awhile but at 220 head, that actualy sounds low?? Is the 3 way bleeding? Maybe the quench?? Hmmm... please keep us posted.

[bellg]

Whats the ambiant? I say 8 degrees should be min. delta.
I have found that the TK's like a condenser bath once in awhile but at 220 head, that actualy sounds low?? Is the 3 way bleeding? Maybe the quench?? Hmmm... please keep us posted.
When you say 'null' do you mean do you mean the fridge is going out on 'stat?

[The Fox]

do you mean the unit is shutting down at -8 or are you losing the deltaT at that temp. please be more specific.

[Andy Longhurst]

In the past i have had problems with the scroll compressor at lower temperatures