Boiler Leaking Water

A leaking boiler in a cellar full of old wiring and wood joists isn't something to watch overnight, so call and describe where the water is coming from.

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When this becomes an emergency

Water is pooling on the floor beneath the boiler or running toward the drain.
The pressure or temperature gauge has been climbing past where it normally sits.
The pressure relief valve is dripping steadily instead of just venting occasionally.
Rust streaks are showing up on the old cast iron where none were before.

What a pro does

A leak rarely means the boiler itself has failed. In the triple-deckers and capes common around here, the usual suspects are a worn pressure relief valve, a failing circulator pump seal, or a corroded fitting on decades-old cast iron, and a tech traces the water back to its actual source before touching anything else. High pressure that keeps forcing the relief valve open usually isn't the valve's fault; it traces back to a waterlogged expansion tank instead. Cutting power and shutting the boiler feed valve is the safe move until someone gets eyes on it.

Frequently asked questions

Does a dripping relief valve mean the boiler is about to fail?

Not on its own. A relief valve dripping under high pressure is doing exactly what it's built to do, though the root cause, often a waterlogged expansion tank, still needs attention.

Is it normal for an old cast iron boiler to leak a little?

No amount of leaking on cast iron is truly normal. Even a slow weep at a fitting will eventually rust through the section it's sitting on.

Should the boiler be shut off if it's actively leaking?

Cutting power and the feed valve is reasonable if the leak is active and near electrical components, since standing water and old wiring in a cellar are a bad mix.

Does this only happen in winter?

It's more common in winter simply because the system runs harder and longer, but a bad seal or valve can let go at any time of year.

Boiler Leaking Water?

Get connected with a local pro now.

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