hi, and welcome,
what size chillers ? and what volume of brew do you need to chill? Usually a single chiller circa 125-150kw will suit most home/micro breweries.
smaller chillers may present too small a gap between the plates to ensure a clear passage for a cold break laden liquor resulting in blockages at worst or residual break and hop debris,trub resisting a backflush clean. Requiring lots of post kettle filtering.