Boiler Piping Layout

jdb2919

Hello, I am installing a wood pellet boiler (MBTEK Phoenix 30) that will connect to a hydronic heat exchange in my forced air plenum. The pump is a combo unit with condensate protection built in. This will be a closed loop system that is not plumbed to a city water feed line. I will fill the boiler through a valve via connected hose and top off manually when the water level becomes low, then disconnect the hose. I am wondering if the attached diagram has the necessary components and correct placements. I would greatly appreciate any feedback!

hot_rod

That will work

one small change would be to put the purger/ expansion tank closer to the boiler, right in that horizontal line before it branches down to the pump/mixing valve

a buffer tank may be in your future unless you are able to control the fire to the heat load accurately 

It could also be an over heat tank 

jdb2919

Thank you for the great suggestions and appreciate your help! I think I follow you on moving the expansion tank closer and that makes sense.

I added a drain valve as the boiler apparently includes an optional drain line. Do I have adequate shutoff and bleed valves to purge air out of the hydronic loop when I am filling the system?

hot_rod

isolation on all sides of the pump module might be a good investment  Some of those blocks have isolation built in.

use ball or gate valves for the boiler drain, or any purge valves really. The Webstone purge ball valve is handy. It allows you to purge both directions

probably an auto air vent at the coil also, with isolation