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Revolution condensate piping

I somehow managed to miss this thread and felt a need to respond to it at Rob's request. The Revolution condensate drain connection needs to be piped either into an approved drain connection or into a condensate pump which will in turn be piped into an approved drain connection. Depending on the ambient temperature of where the boiler is installed and the amount of vent piping, some make more condensate in the flue than others. The aquastat needs to be set to 210°F on the Revolution boiler in order. This has to due with the internal variable speed blending and the ability of the boiler to handle return water temperatures as low as 55°F. Do not change the aquastat setting or it will interfere with the Variable Speed Injection system.

Having the pump pumping against the expansion tank is not a real good idea; particularly if the pump is a larger model which I suspect it may be to overcome the head of the diverter tee system. Larger pumps develop much higher discharge pressures and in this case most of the pressure above and beyond static fill pressure will be lost to the tank diaphram absorbing it. At the same time pressure on the suction side of the pump will drop below static fill pressure and the system will be more prone to becoming air bound.

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.


  • CC.Rob
    CC.Rob Member Posts: 128
    Revolution condensate piping, or not (?!)

    Checking on a friend's house while he's out of town. Old house (1830), had a diverter tee hotwater system installed, probably in the 1950s(?). CI baseboards. Two years ago, he had a Burnham Revolution RV4NSL-L2 installed. Out with the asbestos-clad oil-sucking monster.

    So I'm looking at how the boiler is piped, and notice that there's no condensate line coming out. Open the front. There's the two condensate lines coming down into the white PVC trap/tee. There's a ~4" diameter rusty area on the base tray under the non-plumbed tee. Stick my finger in the tee: condensate! Check the aquastat setting: 210F.

    Am I correct that the reason there has not been more condensate trashing the bottom of the boiler and/or draining onto the basement floor is that this thing is basically set to never condense? Yet it must happen periodically since there's rusting on the base tray plus condensate in the trap.

    Also, the pump is on the supply per the I&O manual, but it's pumping into the PONPC. And the feed valve is plumbed into the main return to the boiler rather than at the PONPC connection.

    The solution to the lack of condensate piping is pretty obvious, especially because I think there's a floor drain available. Even if not, simple buffer and pump setup should take care of it. The pump/PONPC/feed issue has apparently not produced any problems (e.g., overpressurizing system).

    So is this just a truly poor install, or are there larger issues here that might involve safety or other?

    Thanks for comments.

    Should add that the initial reasoning behind the Revolution was greater combustion efficiency. Although it's presently being utilized in bang-bang mode (outdoor reset coming soon), the long-term goal is going radiant in at least half of the house.
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