Recirc pump question for home.

[Navyblake]

So I purchased a watts recirc pump with built in timer to go right onto the water heater. What my question is can I install this pump in a pre expiating recirc line if the supply going to the pump is 1/2”. The pump has 3/4” inlet and outlet so I’m worried about restricting flow. Let me know if any of you have any experience and or knowledge about this. I will include a couple of pictures

 

[MicEd69]

I assume the second picture is your existing pump. It already has a reduced suction and discharge, and this pump will be just fine as well. This is a centrifugal pump, and the flow it provides will vary based on the head the system requires. So, with smaller piping, the friction drop will be increased, and the resulting flow rate will be lower than if it were connected to 3/4" pipe. But the pump will still function just fine in circulating water to maintain hot water at each fixture. And the lower flow rate will also result in lower power consumption. I would insulate all the piping in the recirculating loop, however.

 

[breplum]

I wouldn't recommend that pump for your situation. The union kit alone is too much trouble for your piping and the flex connectors unnecessarily problematic.
It will work, though.
BTW, systems with recirc should utilize long sweep elbows to prevent erosion. I've replaces so many failed elbows.