Lochinvar KB-399 anp pumping away

Riverrat35

My qestion is , how do you apply pumping away for this boiler.my install is exactly like page 36 of this attachment of lochinvar Io manual.system is old one pipe steam.3 story house.replacing old hydronic system with kb399.i have pumping away book by dan.i cant figure out how to plumb the expansion tank to satisfy the lochinvar manual and the pumping away concept.

Steve Ebels_3

As with most M/C boilers they need a primary/secondary type setup for the near boiler piping. Most manual specify that the primary/boiler loop circ must be flowing toward the boiler. This is correct because it's an advantage to keep boilers with small volume heat exchangers under pretty good pressure to avoid flashing. Many of the manufacturers have incorporated pressure switches that will drop the burner when pressure falls below 10 PSIG.

The pumping away theology calls for the cir to be flowing away from the point of no pressure change. Otherwise known as the point where the expansion tank connects to the piping.

The two are not incompatible. Simply pipe the primary loop as the manufacturer describes. Your secondary loop will interface via the typical closely spaced tees. Then simply place your expansion tank downstream of the tees and the system circ after that. Presto! You are now satisfying both requirements. It works like a charm.

A recent example of the advantage of pumping away fell into my lap a couple months ago. While looking at a rather large boiler system in a state correctional facility, I noticed the old fashioned piping arrangement near the boiler. Six ancient B&G 1/2hp circs were located right on the return lines and flowing directly into the boiler. The tapping for the expansion tank was right on the boiler and the exp tank was connected there. While walking through the facility the maint guy I was talking to pointed to the hydronic fan coils on the ceiling of the gym and used a few choice words to describe the stress caused by having to constantly bleed air out of them. I went over the pumping away concept with him and showed him what had to be changed in the boiler room to create a pumping away scenario. They took the advice and swapped things around. Long story short, after moving the circs around to pump away the system basically self purged and the fan coils 20' in the air have not locked up since.

HERE'S TO PUMPING AWAY!!!!!

Riverrat35

one pipe to hydronic lol

yall must be laghing your butts off right now, its 2 pipe

Paul Rohrs_4

When I can....

I will drop a tee down for the expansion tank prior to my closely spaced tee's. Hope this helps.


Regards,

PR

Riverrat35

that's it

thank you . what i wanted to do.pumpin away. needed some moral support