Blast Chiller high suction pressure

[properdouble]

Hi
My friend went to replace evaporator coil on Williams Blast Chiller WBC20.He has changed coil and TEV both parts from williams and charged according to label 2kg of R404a .unit run down to -2 and cu out.He left site and 6 days later they rang saying it is not running.He went there today to find 200 psi high side and 100 psi suction pressure which was the case when he left it originally.Suction coming back cold and heat on the condenser but unit not running properly very slow like for a blast chiller. he carried out pump down test and said it is pulling to zero and then just below.Now he is booking compressor for replacement and i just wonder if it will sort problem or is there something else that need looking at ,completely lost on that one. when we phone williams they said it should be 1.4 kg as label is wrong lol so he decanet it today and put 1.2 still same pressures and results.
Many thanks.

[monkey spanners]

I would expect a recip (L'unite?) compressor to pull down and hold at least 15"hg, maybe even 20", so it does sound like bad valves etc.

[install monkey]

had a recip on a freezer- only getting to -10 , suspected pot weak- pumped down only to 10 inch vac- replaced pot,-21 and capable of pulling a 17 inch vac as monkey says

[properdouble]

brilliant lets hope that it will run ok when he goes change compressor.
Thanks.

[mbc]

in all systems vacuum is very important especial in small systems .
also in low temp it is better you put one extra low pressure control that control your solenoid valve ( if you have high pressure in suction pipe in starting time it close the solenoid valve until it comes down in large system) or you can use crankcase pressure regulator to protect your compressor and high pressure in condenser during stating time.