Hi Guys.

We manufacture stainless restaurant equipment.
We built in 2 ice cream wells into a remote buffet table.
These wells are 50" x 11" x 15" deep with 3/8" copper tubes wrapped around and spot welded tightly to them several times around to approximately 90' worth on each.
The walk in cooler guys took the contract to hook them up. Complaint is that they won't come down to temp. They are using 448a gas. 2 HP compressor seems more than adequate.
They tried in parallel and then went to series hook up and same issue.

We have made these identical wells for approx 22 other locations over the last 25 years, where they probably used 404a.

Is the new gas just not good enough? Do we need to use 1/2" tubes around the wells? More length, but same size tubes?

Any ideas appreciated.