need some help with dryer problem

[paul441]

Hello,

Got this problem with a dryer,fitted new comp on it and thought it was fine,but after few hours being on-line for the air compressor the pressure drops by half when compressed air goes through dryer and its ok when bypass dryer,anyway my dryer has a normal dp of 3 degrees my lp pipe cold and hp hot ,fan comes in etc .but i have noticed when unit off and put gauges on lp shoots round to retard and when switch dryer on and comp kicks in my lp goes to about 6 bar and hp to 15 bar.I soldered joints on could i have blocked it doing to much.i need to go back to this job monday can anyone give me some advice as what i need to do . also had call from customer who said top of comp freezing
cheers

[chemi-cool]

Make, model and refrigerant please.

[paul441]

Its an highross dryer and it r407c 2.3kg, cheers

[Brian_UK]

Did you weigh in the refrigerant charge after evacuation?

[paul441]

Hi Brian
Yes charge weighed in 2.3kg r407c
cheers

[chemi-cool]

Have you changed the drier on the liquid line?
What sort of compressor doe's it have?

[AUScooler:-)]

So what is restricting the pneumatic air supply?

[chemi-cool]

Ice stops the air from passing through.
The reason is in the refrigeration system. From some reason evaporator pressure drops and the water freezes.
It can be in the metering device [cap tube or TXV], liquid line drier, too much charge or set point of the hot gas pressure.

Have them checked carefully and see if the water outlet SV functions well.

[glenn1340]

Has it got a hot gas valve? if it has it might need a tweek to increase the low pressure slightly. Unlike a TEV you`ll not upset any delicate settings by adjusting it, in fact you should see the suction pressure rise as you slowly turn the adjuster in and fall as you screw it out.

[paul441]

Thanks for your advice i will try that,
cheers