System not cooling well

[bagger]

I need help figuring out a system that is not performing very well, nor has it ever from what I am told. I have two systems installed in a small house that has been converted into a restaurant. A 5 ton that is used to cool the dining area that works fine. The problem system is a 2.5 ton straight cool with a fixed orifice and no electric heat that is used to spot cool the kitchen. Both the supplies and returns are located in the kitchen and are the correct sizes. Neither of the coils are heavily soiled and the Freon charge is very close: delta-T – 85/75 degrees; ID wet – 76 degrees; OD dry - 91 degrees; suction line had 83 psig at 78 degrees; liquid line had 303 psig at 127 degrees.
To me, it seems because of the high heat load, the system might need a larger piston (if so, about how much larger) and/or add some cooler return air from the dining room into the kitchen. What would you suggest?

[beenthere]

Sorry, this is not a DIY site. So we are not allowed to give out advise of this nature.

Since answering your question in the open Residential Forums would be posting instruction for DIYers that may read this post later.

If your in the trade, get your post count up to 15, and apply for Pro Membership.
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But. You might want to think about how clean those coils aren't.
2.5 tons isn't much for a kitchen. It may never be able to really cool the kitchen.

[bagger]

Thanks for your assumption. But this is my trade, it has been for about 5 years. As far as needing 15 posts before I can apply to be a Pro member, well it just not going to happen. I probably do not have 15 post total in my life. I may get on a few forums to read from time to time but I don’t post on them.

[beenthere]

Sorry to hear that.
We have a large group of experienced techs to cover most areas of the trade.
You should reconsider.

[AACHP]

Been my experience that a commercial kitchen -- even a small one will eat up 4-5 tons very quickly. Sounds like you are undersized and larger piston won't help.

[Zugzwang]

I agree with AACHP. Have you done a heat load calculation?