Gas Water Heater Repair & Installation in Canton, GA

A small puddle under the discharge pipe on the side of a gas water heater worries plenty of Canton homeowners, and with good reason. That pipe comes from the temperature and pressure relief valve, the device that keeps a tank from building dangerous pressure. Alpha Plumbing and Sewer treats a dripping relief valve as part of gas water heater repair, because the valve is usually reacting to something else in the plumbing.

What the relief valve does

Every tank-type water heater has a temperature and pressure relief valve, often called a T&P valve, threaded into the top or upper side of the tank. It opens if pressure or temperature inside climbs past its rating and releases water through a discharge pipe that runs down toward the floor or to another approved spot. On a gas heater, a control that fails to shut the burner off could overheat the water, and this valve is the backstop.

Why a relief valve drips or discharges

• Thermal expansion: water expands as it heats. If a check valve, backflow device or pressure-reducing valve keeps that extra volume from pushing back toward the street, pressure in the house rises every time the burner runs.
• High incoming pressure: without a working pressure-reducing valve, street pressure alone can creep toward the valve's setting.
• Overheating: a thermostat set very high, or a gas control that does not shut off properly.
• A worn valve: mineral deposits or age can keep the seat from closing fully after it has opened.

A valve that drips briefly after each heating cycle and then stops is often pointing at expansion. One that runs steadily, or releases hot water with force, needs attention right away.

What not to do

Never cap, plug or shorten the discharge pipe to stop a drip, and never swap the valve for a plug. A blocked relief valve removes the protection the tank depends on. If the valve is releasing very hot water or steam, turn the gas control to off, close the cold supply valve to the heater and call a plumber.

How we find the cause

We start with a gauge on a hose bib or the heater drain to read static pressure, then watch how it changes while the burner heats the tank. A steady climb during heating confirms thermal expansion. We check the thermostat setting and whether the burner shuts off at temperature, and we look at the relief valve's age and condition. The fix might be a new relief valve, a properly sized expansion tank on the cold supply, repair or replacement of the house pressure-reducing valve, or some combination.

The discharge pipe on a new installation

When we replace a gas tank, the new heater arrives with its own relief valve. The discharge pipe is run full size and downhill, with no valve in it and no cap on the end, to a place where a sudden release of hot water will not spray anyone or ruin finishes. Where the heater sits above living space or in a closet, a drain pan with its own drain can catch a release before it reaches the floor. We follow the manufacturer's installation instructions and the code the local office enforces. An electric water heater depends on the same kind of relief valve, and most tankless water heater installations include a pressure relief valve as well; our statewide water heater guide covers all three types.

Moving a heater or changing pipes in Canton

Canton's Building and Safety Services Department says replumbing a house, or adding any new supply or drain line, needs a permit first. That comes into play when a replacement moves the heater and fresh supply lines have to be run. For a straight swap in the same place, we confirm with the department what applies.

Questions about water heater relief valves in Canton

Should I test my relief valve?

Many manufacturers recommend lifting the test lever from time to time to make sure the valve opens and reseats. Set a bucket under the discharge pipe first, because the water will be hot. If the valve keeps dripping afterward, or will not open at all, it should be replaced. An untested valve on an older heater may not reseat, so plan the test for a time when a plumber can follow up.

Do I need an expansion tank?

If your home has a check valve, backflow preventer or pressure-reducing valve that stops water from flowing back toward the street, heated water has nowhere to expand, and an expansion tank is often the answer. A pressure reading during a heating cycle shows whether pressure climbs. The tank is sized to the water heater and the house pressure, and its air charge is set when it goes in.

Is a dripping relief valve dangerous?

The drip itself means the valve is doing its job, but it warns that pressure or temperature is reaching the limit, or that the valve is wearing out. It is not something to live with for months. A heater that keeps pushing its relief valve open is working under stress, and the cause should be found and corrected.

Stop the drip at its source

If the relief valve on your Canton water heater will not stop dripping, phone Alpha Plumbing and Sewer at (404) 409-4448; a pressure reading is usually where we begin.