Hot water preheat - question on config and low temp issue

rjc2000

Looking for some advice on figuring out an issue with the domestic hot water, using a Tranquility 30 geothermal for preheat. Will try to make a long story short. after having replacement AO Smith tanks fail, replaced both tanks with a Rheem 50 Elec and a Rheem 50 gal storage tank. Phase 1 of replacment did not inlcude connection to storage tank, just a direct pipe to electric tank. Water temp was much higher than with AOSMith tanks, attirbuted it to better new tanks…enjoyed the nice hot water, probably around 124 deg. Then a fewe weeks later , had storage tank connected as image shows. We normally leave recirc closed/off, its purpose was for a sink that is not always used. After the storage tank was connected, water temp at faucets was much lower, in the 115 range..pressure may be lower too, especially in shower, but also due to low temp, we do not need to mix in any cold water at shower faucet so that could be the lower pressure. If i bypass the preheat tank and turn off geo preheat function, water temp increases back to the 124 range. Trying to figure out why ??? Tranquility unit is set to preheat to 125. Top Rheem is set to MED which is supposed to be 120, Bottom Rheem is set to 120. I did just notice the sticker on the tank about non-simultaneous operation, which i also attached. I feel like the preheated water is too hot keeping the electric from actually heating water higher, like when cold/well water enters directly, but i don't understand why the water at the facuet is then colder.

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