Options for water heater/side arm piping?

Drewgrizz

Ok guys question for ya?  I am installing a system in a house right now using a Lochinvar boiler with a primary/secondary setup with a ecm pump to a manifold off the primary circuit running out to 9 Myson radiators homeruned back to another manifold.  I am going to run a 220v water heater with a sidearm on it so I can use the extra heat from the oversized boiler in the cold months to save alittle money and help the boiler not the short cycle.  My question is how should I hook the sidearm up to the boiler?  I was thinking about connecting it to one of the ports on the manifold so its getting hot water when the house is calling for heat (the simplest method), but that means it would only heat the water when the house is calling for heat and I don't know if that would adversly affect anything?  I could run a T off the primary ciruit with its own pump, but that would be using a giant boiler to heat my DHW and the ecm pump would probally kick on when it sensed the boiler working?  I dont want this system to get to complicated, I am using 1 thermostat to control the boiler and ecm pump to keep up the the heat demand and TRV's on all the radiators.