A customer has a commercial dishwasher which requires a minimum of 20 psig (hot) water pressure during the rinse cycle only. With no flow in the system, the city pressure is 55 psig measured at the dishwasher, but it drops to 12 psig when the rinse cycle begins. I'm estimating the rinse cycle will use about 10 gallons in the 40 seconds it operates.

Repiping his entire water system to eliminate the low pressure situation is not feasible, but it seems to me that the installation of a bladder tank at the inlet to his water heater would solve the problem. (Obviously, a check valve would be required at the bladder tank inlet to keep the water from flowing back into the piping system.) When the rinse cycle ends, the water pressure would return to 55 psig, at which time the bladder tank would refill, ready for use again.

Do you see any hidden surprises here? I'd be grateful for any thoughts!