reset and mix or injection

tim smith1

Calling all, got a 1 million btu boiler, power burner, dual fuel. Trying to decide on the benefits of full reset down to 100 degrees let say or minimum temp, appx 140 with boiler only reset. On top of it all, if full reset, 3 or 4 way mix or injection. Injection a little hard on this size. Come one come all. Input a good thing.

Ken Wickre_3

tekmar Injection Mixing

With the larger 1/6hp wet-rotor pumps from Grundfos, you can inject a significant amount of hot water into a low temp system. For example, a UP 43-75F could deliver 38GPM @ 5' head. Look at your system requirements, - i.e. design boiler temp, design system temp, temperature drop - and calculate your injection rate. Most likely you could use injection. If so, a tekmar 361, for example, will give you full reset on the system side, boiler load reset on the boiler side (the boiler supply temperature is raised only enough to provide the required system temperature), and minimum boiler temperature (boiler load reset temperature will be somewhere between minimum boiler and design boiler temps). And if you prefer a mixing valve, I would look at the floating action control equivalent of the 361, the tekmar 360, and utilize a 4-way mixing valve with operator.