I've got a Whirlpool WHER25 RO system. Recently I added a hot water dispenser to our kitchen sink as well and would like to route the RO product to it instead of running it off of unfiltered water. The hot water dispenser requires 30psi to operate properly. My RO product water is 42psi when the tank is full, but the pressure drops rapidly into the 20s when the tap is turned on. Currently the stock system looks like this:
To ensure I get the necessary pressure to the hot water dispenser, I'd like to install a permeate pump to bring up the tank pressure close to the 68psi going into the system. I've found out that's difficult with a WHER25 since it is a manifold system and I can't add tees willy nilly anywhere I'd like. I'd also still like to be able to use the post-filter as intended - when the product water is dispensed and not before going into the tank. This limits my options since most people with manifold systems relocate the tank to after the post filter.
I think I've come up with a solution using another automatic shutoff valve in a different place in the system. Does this look like it will work or am I going to end up breaking something? Not sure if I'm correct, but I think this should only allow water out of the tank when there's a significant drop in pressure on the product out line, like when the tap is opened or the hot water tank is filling.
Additionally, does anyone know where to get an automatic shutoff valve with 3/8" push fit or JACO connections for both the high and low side or am I going to be stuck with a bunch of reducers? The only one I can find is the Payne PWS-792Q, but I can't find a distributor offering it. If I am stuck with reducers will they ultimately end up limiting my pressure or throughput?