What is this component

Tom Sherman

Greetings! I'm hoping someone can help me out identifying this component. It's on the feed side of a 13 year old steam boiler. Thanks in advance!

Jamie Hall

I'd say, off hand, that it is a whacking great pump attached to the side of a condensate return tank. If it's controlled by the boiler water level, it's a boiler feed pump. If it's controlled by a float in the tank, it's a condensate return pump.

Tom Sherman

Thanks Jamie,
It's on the supply side of the boiler. There is also an open-to-atmosphere pipe exiting the box and leading to a floor drain (This is the main question...not sure what this box is for). At first I thought it might be related to feeding a hot water zone off the return condensate, but its just downstream from the auto-fill valve. I haven't heard of a whacking great pump. Any chance you can elaborate? Much appreciated!

JUGHNE

Boiler feed pump:
The condensate return water from the steam system flows into this box. When the boiler needs water, a control on the boiler calls for the pump to run.
The red PEX to the right of the pump is a cold water supply connection. If the box gets too low then there is a float inside that operates just like a toilet tank fill valve.
You do not want to add more fresh water to the system after initial fill. The water should return to the tank/box from the system quick enough to not require fresh water.

How about more pictures showing the entire boiler piping from floor to ceiling?

Jamie Hall

The big tank -- box -- is a condensate return tank. The open to atmosphere pipe is the vent for the tank -- and it leads to a floor drain, as if the tank gets overfilled, you really don't want the water on the floor. The tank serves to collect the condensate returning from the radiators, and the pump serves to pump that condensate back into the boiler.

"Whacking great" is, I guess, an old-fashioned term for a device -- in this case, a pump -- which is probably rather bigger than it needs to be for the purpose.

JUGHNE

The pumps are usually bigger than needed, too much water too quick knocking down your steam production. They need to be throttled down to avoid this.
The larger tank is to your advantage if you have slow condensate return in the system.

Tom Sherman

Thanks Jughne! Makes sense! I haven't seen one of these before, though have seen plenty of steam boilers. This is 550,000 BTUs...big boiler. Might that be the reason I haven't run into one before?

JUGHNE

Looks like condensation on the flue pipe.

Is that a monitor camera on the tripod?

Tom Sherman

Yeah, condensing flue gas has definitely been an issue. It's a radon monitor on the tripod.
One more pic. Any thoughts on the corrosive staining on the floor around the base of the cabinet?

JUGHNE

Boiler could have a leak inside.
With power off you can over fill the boiler up to the header and see if any water leaks onto the floor after a half hour or more.

In the winter you might see white steam coming from the chimney outside....indicates steam leaking into the flue gases.

You can back fill thru the boiler drain with water from the water heater drain valve. Double female hose fitting needed....washer machine hose would work.

JUGHNE

This looks like it is or was a form of low pressure vapor 2 pipe system.
The big "Ham" to the left of the water heater is a form of boiler-return trap.
Originally this was most likely gravity return without any pumps.

Someone else here can tell you more.

What is the operating pressure of this system?

Tom Sherman

Thanks for the info. This was in a house I was inspecting. There was an additional return trap on the far side of the basement. The pressure gauge was not showing anything after operating for 1/2 hour, so the gauge may not work. Here's a pic of the other return trap

JUGHNE

You are a real estate home inspector?
If so you are a rarity, to ask questions about something you have never seen.
Most would probably just say it works and check it off as OK.

IIWM, I would notate/advise the perspective buyers to have the boiler checked by a steam pro for leakage prior to signing anything.

Where is this located?

If leaking it is potentially several $1000 to change out.

Tom Sherman

Thank you! That's how I learn and I've learned a bunch just hanging out here on HeatingHelp! Appreciate your advice!

Tom Sherman

Thank you again gentlemen, for your help and for sharing your knowledge! It's great to have a place to come when I run into these unusual situations! Much appreciated!

mattmia2

A few things look wonky about the piping as well, especially the header, It really should be inspected by an expert that can say if any piping has been misrouted over the years causing problems with bringing water up in to the piping with the steam (which might be how it got a condensate tank).

Steamhead

First time I've seen a Vapor system that has TWO Return Traps. I think those are Dunhams.

Where is this located?