Damp spot under boiler. What is leaking?

JH3550

I found this damp spot under the spigot on the bottom corner of my boiler. It looks like it is very slowly leaking. I'm wondering, What exactly is leaking and what do I need to have replaced?

Weill McLain steam boiler. One pipe steam. Boiler was installed in 2002, but I just moved into the house last year  

thank you!

DCContrarian

Looks to me like the boiler drain itself is leaking, in the second photo I think I see a bead of water and it looks like it's covered in mineral deposits.

I would replace it with a ball valve style boiler drain.

PRR

It's just the factory valve to drain or blow-down the mud out of the boiler. Has someone been blowing it down monthly? (LWCO too.) If not, you probably want an experienced tech to do it (including unjamming and re-washering/replacing) while you watch.
The drip is not a huge problem but if "mud" (iron oxide and other crud) builds up in the boiler the bottom sheet will melt, which is dangerous and expensive and bad.
There's a burner-service company sticker. I'd call them first.

Mad Dog_2

You lucked out...easy one. Mad Dog 

JH3550

PRR said:

Has someone been blowing it down monthly? (LWCO too.)

I blow down the LWCO once per week. I’ve never touched the drain valve. No idea if the previous owners did. 

thank you all for the advice!

DCContrarian

A quick fix is to put a cap over the drain, like this:
https://www.amazon.com/gp/product/B085ZR3J47

I put those caps on anything with hose thread as a matter of course, make it a two-step process for anyone to accidentally flood the house.

You do want to replace that valve eventually. Usually what happens is once they start leaking if you ever have to open it the leaking gets much worse when you close it.

nicholas bonham-carter

It looks like the threads of the valve body may be leaking, judging by the green sheen covering the outside of the valve. Replacing the valve with a full port ball valve may fix that for good.—NBC