No gas: water and freeze-ups. Episode forty-seven of the Gas Service Animated series.

Gas is supposed to be dry, but it never quite is — and where water gets into a gas line, it either pools and throttles the flow, or, when it's cold enough, freezes solid and stops it. Water in the gas line is a real no-gas cause, and it has a season.

Water gets in more ways than you'd think. Ground-water seeps through a crack or a leak. A main washes out or floods and pushes water down the services. The water table's high. Even a brand-new line holds water left over from its pressure test if it wasn't dried out. And once water's in a main, it spreads far and clears slowly — you'll see low pressure across a whole stretch of customers, still there after the leak's fixed.

Inside the picture, water obeys gravity. It collects in the low spots and sags of the piping and physically throttles the gas before it ever freezes — a chronically weak flame at an appliance fed through a dip. And it settles into the very place the code puts to catch it: the drip and the sediment trap. When that low point fills, the house loses gas — and in winter, that's exactly where it freezes.

Then the cold turns a nuisance into a shutdown. The moisture that's always in the gas condenses, and below thirty-two degrees it turns to ice and blocks the line. The regulator makes it worse: gas cools as it expands across it, six to eight degrees per hundred pounds of drop, so on a cold high-demand morning ice forms right on the diaphragm and the regulator freezes off. One frozen point can take a whole building down.

And the winter vent. Snow and freezing rain that melts and refreezes will cap a regulator's vent, and a meter set buried in a drift or under a roofline's ice dam freezes and blinds. That's a no-gas or erratic-pressure call on the coldest morning of the year — and in the worst case, a sealed vent is a safety problem, not just a comfort one.

Under the ground, there's frost heave. When wet soil freezes it expands and shifts, and that movement is the single biggest cold-weather cause of gas distribution trouble — it loosens joints on shallow, threaded, and older pipe. So a hard freeze can show up as a new leak and a loss of service at the same time, out in the yard where nobody's touched anything.

So how do you clear it? For a water-blocked or frozen low point, you blow it down — open the drip or blow-off at the low point and let the water and gas discharge until it runs dry gas, done with proper purging, ventilation, and ignition control. You thaw and dry a frozen point. But the real fix is the source: if water keeps coming back, there's a leak or an infiltration to find. This is where a no-gas call is often utility and emergency work — thawing services, injecting anti-freeze, chasing a wet main is their job.

A February call. House lost heat overnight, coldest night of the winter. Meter's live, but the regulator vent is glazed with ice and the drip at the low point is heavy with water. Thaw the vent, blow the drip down to dry gas — and then flag that recurring water, because next cold snap it's back unless the source is found.

Water and freeze in one breath. Water gets in through leaks, floods, and un-dried new pipe; it pools in low spots and drips and throttles flow, and in the cold it freezes and stops it. Regulators freeze off; vents ice over; frost heave breaks joints. Blow the low point down to dry gas, and find the source. Next: the appliance that won't fire.