What am I looking at here?

AK_TK

Can anyone help identify what this is? All I have been told is that it is installed on a hydronic heating system here in Alaska.

EBEBRATT-Ed

Flow check valve. It prevents gravity flow of water when the boiler is used with a tankless or indirect water heater.

A flow check is a weighted check valve and only allows flow when the circulator is operating. It should have a lever or other means to open the flow check or keep it in the auto position. It is kept in the auto position normally. Open position is so you can get gravity flow if your pump fails

bburd

That is a flow control valve, a weighted check valve. It stops heat from rising out of a boiler by gravity flow into a hot water radiator system after the thermostat stops calling for heat and shuts off the circulator pump.

The normal setting is in the middle, marked “winter”. If the lever is set to  “open”, the valve will stay open and gravity flow will be allowed; this is useful if a circulator pump fails, some heat will still be provided. If it is set to “closed” heat will not circulate.

Steamhead

The lever on that one has been broken off. It used to point to where it says "Open", "Winter" and "Close".

EdTheHeaterMan

Steamhead said:

The lever on that one has been broken off. It used to point to where it says "Open", "Winter" and "Close".

If the system is operating properly, then the broken handle would be pointing to WINTER
Here is a short description of Flow Control Valves on page 8 of this
booklet https://www.xylem.com/siteassets/brand/bell-amp-gossett/resources/technical-brochure/fh-z100b-bg-zoning-made-easy-2.pdf

Flo-Control Valves Control Overheating,
Not the Flow!

Maybe “Flo-Control” was a bad name to give to this device back in the
old days when we were converting gravity hot-water systems to forced
circulation. The industry needed something that would stop the
hot water from rising up into the radiators when it wasn’t needed.
Hot water will do that, you know. It’s lighter than cold water.
But the name Flo-Control valve makes some guys think they can
balance a zoned system by turning the top levers on the valves.
That’s not what those levers are for.