Recently had a new A/C system installed by a local contractor. The air handler is a 2 yr old Amana unit and the new A/C system consists of a York Affinity 4 ton R-410a with an Aspen coil. The techs seemed to have a hard time fitting the coil into the box under the furnace and hacked away a bunch of sheetmetal to get the refrigerant and drain lines in. They sealed up all the gaps as best they could with a aluminum backed insulated tape. The system worked okay for a few days but the tape seems unable to hold back the pressure and leaks a lot of air when it runs. Now the system barely works at all there is a thin oily film all over the tape near one of the coil fittings. I'm having the company back out soon to fix it.
Is taping up large gaps in the coil box acceptable pratice, if not what should I insist be done?
Are the air leaks a problem?
Does the oily film indicate a coolant leak?
Thanks in advance,