Im an ac/ refrigeration engineer by trade.
I persume he knows its a blockage because you have a high discharge pressure and low suction pressure? If its just a high discharge pressure this could be because the fans arent running, they should be on low at all times when ac is on, and depending on ambient will cycle between high and low fan speed.
With out going too technical, but theres a capillary tube in the system between the high and low side, this is know as the expansion device and is basically a very small bore tube, this can easilly get blocked but is rare unless your ac system has been open (rads off due to crash etc). Or the capillary can get blocked by moisture, which can be due to bad practice or again due to the system being open, but the moisture can be removed by a good evacuation.
Im not directing this at the place that did your work, but a lot of garages that offer ac
repairs arent that specialised in the industry, they just plug it in to the machine and can sometimes misdiagnose it.
A simple check yourself is turn ac on and see if fans run on low speed, allow it to run for 5 to 10 mins and see if the high speed fans run on and off, if they run on high speed all the time it could be a blockage or over charged( too much refrigerant put in). If the fans dont run at all that could explain a high pressure
problem as the fans cant remove the heat, more heat = more pressure.
Keep me updated or pm me for more info, im on my iphone atm so its annoying writing too much, but could reply on laptop in future. Jack
