AboutCraig HVAC Expert Expertise I have been in the HVAC field for the past 12+ years. I can help with most HVAC questions. I work on commerical buildings for the most part, and have yet to find anything I could not troubleshoot and repair, when repairable. I work on small 1 ton units to a 2500 ton chiller. Troubleshoot air flow, elect, and control problems. I attend regular classes to keep up with the latest and greatest.
Experience I have work in the HVAC trade for the past sixteen years. I work on commerical sites, hospitals, gov't buildings. I can troubleshoot just about anything in the HVAC business.
Education/Credentials 5 years union trade school, VFD training classes, Liebert factory training, some York and Trane factory training.
Question we have AC contractor for our retails store area around 7000sqmtr of 2storey building we get supply of chiller line from Mall and in side units of stores are maintained by our contractor, here during summer high time Mall maintenance play with us to save cost of energy neither they allow our contractor ro check GPM flow , so our management had decided to installed pressure gauge and temp. gauge to first nearest unit of Mall chiller line ,i would like to know how can i calculate through pressure gauge whats gpm is supplied by mall chiller line???
our units are 5 years old we have replace our units aluminium filter from double to filter to single line filter and also chemically cleaned evaporater line still during this summer every time we face low cooling. please help me out how to calculate gpm by pressure gauge.
Thanks
Answer You can not get gpm with the gauge alone. You have to know what the design flow at a give pressure drop. The manufacture will tell you that if the pressure drop = x then the gpm = y. There are devices that can be installed in the piping that will give you a gpm. The devices are set up for a give pipe size, and using velocity the gpm is then known. You could have a case where the system just can not handle the high heat demand, and not the mall trying to save money.
