Thanks everyone for your helpful suggestions. DX VAV without economizer certainly is a nightmare, and something I'll not want to repeat again. I've learned more about the DX controls lately that should help the situation out. The condensing unit is two-stage (2 compressors) with hot gas bypass...
Thanks ChasBean1 for your reply. I need to clarify a few things: 1)There is reheat at the VAV boxes; 2) the discharge air is maintained between 50 and 60 depending on OAT; 3) the cold blow problem was mininmized when we added the DAT reset.
The main problem, now, is related to capacity as you...
It's been my experience that when a constant speed pump is running the variable speed pumps have to operate near full speed to match the system pressure created by the constant speed pump. We have run chilled water systems designed with more than one operating pump by operating the pmps in...
I have a VAV air-handler with a DX cooling coil (two-circuits, intertwined) with a two-stage condensing unit (operates on its own pressure controls). The unit also has hot gas bypass (mechanical type) to allow compressor operation at low loads. Due to 'cold blow' complaints when the boxes are at...