Thermostatic + recirc: how to fix?

[ted1209]

Hi there. I have a recirc system with a thermostatic mixing valve. The tmv puts out the desired 120 degree water when the hot supply is 125 and the cold supply is 115 (due to the recirc return). When the cold supply goes to 50 (due to hw draw) the tmv output drops to 105 or so. The result is I get hot water for a bit, but then it drops off. The tmv is set to its max hot setting.

I found this link on the forum: https://www.hpacmag.com/features/recirculating-domestic-hot-water-system/ Mine was setup “the incorrect way”, but I’m not sure adding the two valves will fix my issue as my problem starts when cold water returns to the cold supply of the tmv.

I also note that my tmv, a CashAcme Heat Guard 110D, suggests an operating range of 39 to 80 degrees for the cold supply, so maybe this is the issue, that the return into the cold supply is putting the tmv out of range?

Any thoughts are greatly appreciated.

 

[Breplum]

Recirc return should be piped into the WH directly, like at the WH tank drain, down low.