Weil Mclain CGI 6 and Tekmar 360

swain

Hi All. New to the wall here. Have learned a bunch reading the various threads.
Now to the story. We bought this house recently and it has a Weil Mclain CGI 6 (Only a year old) and a 4 way mixing valve. The system was put in the house in 94 and not much as been changed except they replaced a Weil Mclain cg6spn boiler with the CGI. Right now the 4 way valve is controlled manually. Im looking to put the Tekmar 360 with the tekmar 741 actuator on it to increase the efficiency and protect the boiler from cold water return. The system has 2 pumps. One after the 4 way mixing valve and one on the return to the boiler. The boiler heats 2 fan coils, the basement infloor radiant(No mixing Valve..Another story) and an indirect tank. The fan coils and indirect are setup with zone valves and the radiant uses a watts manifold. Also to note the Indirect is piped in before the mixing valve.

Question is I just want the tekmar to control the mixing valve not the boiler. I know one sensor goes on the mix pipe after the system pump. Do I put the return sensor after the boiler pump leading into the boiler? Also the system pump runs 24/7 and the boiler pump only runs when the boiler fires up. Will this lead to issues with the tekmar control?

Thanks for any help