I noticed every time we replaced a filter the water was slower coming out. It started squealing and I decided to try the filter bypass before suspecting anything else in the system. After putting the filter bypass in the flow increased 10 times. Ordered the head and tank assembly on Sunday and received the shipment on Tuesday. This particular model has the elevator frame assembly for a shelf so it was a pain to R&R the tank/head assembly but, with a lot of cranking it up and down we got'r done.
VERY POOR DESIGN: The manufacturer should never have designed the head assembly push pins, that engage the valve, with plastic tips that come to a point! They wear every time a filter is replaced so the head assembly is only good for about 6 filters!!! Looks to me like they could have used better material like metal or, even better, a ball bearing (similar to ones found in a writing pen) to roll on the filter's ramp... my 2 cents.