I have a dedicated 1/2" recirculation line back to the water heater tank via a tee at the drain valve. I've purchased a new pump (Grundfos UP 15-29) to replace original 15yo. There's a check valve located just upstream of this pump. However, I've seen drawings with the check valve downstream of the pump & upstream of the tee to drain line. Does it matter whether located u/s or d/s of pump? Also, would a "spring" type check valve be preferable vs flapper check valve? Within the recirc line, there's two zones, however, the zone furthest from heater takes over a minute for hot water to faucet. Thinking of installing a valve on the shorter line to throttle back for more uniform circulation to both zones. Is a ball valve OK or recommend other type of valve?
The pump you purchased is way oversized for the application.Instead of the "UP 15-29" pump you should have purchased a UP 10 or a UP 15-10, the smallest pumps they have. Make sure the pumps are made of bronze or stainless steel. Iron or steel pumps should not be used on domestic water. The UP 15-29 moves too much water and may "wipe the elbows" (wear out or wear through) due to the high flow rate. You only need a very low flow rate to insure almost instant hot water flow at the faucets. I have 3 zones for the 3 bathrooms in my home. A check valve at the take off tee for each dedicated return line is imperative to stop "back flow" from the other dedicated returns. I would not use spring checks and use only angle checks due to required head needed to lift the spring checks. I would also install a timer to run the pump only during the day when your household is awake. No need to run the pump when everyone is asleep. continuous running pumps are only used in hospitals and large commercial buildings due to their constant hot water use.