Modular System starting problem

[Mayank]

I am working on design and testing of a modular refrigeration system. When I first start the unit with 90 psi standby system pressure and 105F ambient the suction pressure goes down to 1 psi and is not able to build pressure with low discharge pressures as 145 psi. Now if i switch off the unit and let it stand for 15-20 mins the standby pressure increase to around 120 psi. If i start the unit at this moment the suction pressures does not drop below 16 psi and stays constant their and the unit performs well in the second run. Need help in figuring out the root cause.............

[sedgy]

hi mahank, sorry not understanding you, maybee you have too much refrigerant in unit,
tell us what type of ref,?< are all fans running ?<

[icecube51]

give us more detailed info concerning the design so we can help u in youre surch.

Ice

[Mayank]

The system runs on R134a. It's basically for a visi cooler (with a glass door for commercial applications). The unit comprises of a Capillary tube as the metering device and has been charged with 380gms of refrigerant and has to function in an ambient of 105F. The problem is that when the unit is soaked in 105F for say 3-4 hours, the standby pressure is 90 psi. Now if now i run the unit at no load (i.e. no products in the cooler) the suction pressure goes to 1 psi and does not build up. Am using a HBP compressor where i have designed the system for a -7 evaporating temperature that is 18 psi suction pressure. But instead if i switch off the unit and let it stay for 15 mins the standby pressure goes up to 120 psi and then after starting the unit i get desired results i.e. suction pressure of around 18 psi. am not able to figure out why i am not getting similar results in the first run itself................