How to replace water heater drain valve without draining

In brief, Yes It is possible to replace the drain valve without draining the tank. But you need to be careful about power or gas supply, temperature of the water inside the tank and the flood hazards.

Safest way to replace water heater drain valve without draining the tank

If you wonder if it is possible to replace the water heater drain valve without draining the water heater then the answer is Yes. But you have to be very careful about electricity or gas supply, temperature of the water inside the heater tank and the possibility to flood the floor from water in the heater. So, this is how you can safely replace the water heater drain valve without draining the tank.

Steps 01

Disconnect the water heater from power source. If you have electric water heater, cut of the electricity supply or put the gas water into pilot mode if your water heater is gas.

Step 02

Let the water inside the heater to cool off to a safer temperature. It takes up to 1 or 2 days to come down the temperature of the water inside heater tank to normal level. You can use the hot water faucets, have a bath or wash cloths while waiting for water to cool down.

Step 03

Shut off the cold-water supply to water heater by shutting off the valve.

Step 04

Keep shut all hot water outlets including faucets and showers. If all hot water outlets shut off and cold-water supply is also cut off, then it could create an air lock situation preventing or limiting the water flow when your remove the drain valve. But this is not a guaranteed condition because there could be some opened valves or air inflow from defective fitting joints, cracks in pipes which cause losing the vacuum.

Steps 05

Arrange a method to collect the water that is possible to come out from the drain valve opening of tank when you remove the drain valve to replace it. Easiest and simplest method to collect water spilling from water heater is to use a large pan that can be place below drain outlet level.

Step 06

Get ready with tools, equipment and materials needed to complete the replacing drain valve. Double check and verify that all are okay before proceeding to work. Following items will be required to have with you,

  1. Suitable pipe wrench
  2. Plumbers tape / Teflon tape or joint compound
  3. New drain valve
  4. Garden hose (Better to have a connector that can quickly fix to the new drain valve outlet)

Step 07

  1. Now you remove the old and clogged drain valve and replace it with the new drain valve. You need to be very careful at this step as you are going to remove the drain valve from a tank filled with water. It is wise to have a partner with you so that he or she can help you manage possible water discharge.
  2. After that you are going to replace the old drain valve with new drain valve very quickly. This could be a temporary fix so you do not have to apply any plumbers tape or jointing compound.
  3. If you successfully did the replacement, connect the garden hose to the drain valve outlet.
  4. Place the other end of the garden hose at a suitable discharge point. Open up few hot water faucets and then open the drain valve. See if it is drain out the water from heater tank with a sufficient amount of flow. If it is a very minimal flow, you could try opening the t&p valve also (of course it is safe to operate).

Even after replacing the drain valve, still experience clogged drain, you might have lots of sediments in your tanks they are blocking the drain valve. In that case best thing is to do a heater tank flushing.

What can go wrong if I remove the water heater drain valve without draining

If you try to remove the water heater drain valve without emptying the tank, worst thing would be flooding your floor with 140 degrees Fahrenheit hot water inside the tank. This is could be much hazardous situation if you have electrical sockets/ damaged wires at floor level near the water heater. Therefore, you need to very careful about two important things before removing the water heater drain valve.

  1. Let water inside the water heater tank to cool down to normal temperature that is safe to touch.
  2. Arrange proper method to collect possible sudden water discharge through the drain valve opening after you remove the drain valve having water inside it.

In addition to that always be ready with all required tools, equipment and materials with you before starting the work. And keep another person with you if you need help. Better your children keep away from this operation. Once I heard a story from a DYI plumber in Columbus about what he did to a blocked drain valve. Here it is,

“On my prior water heater, I tried to drain it and it was clogged. Not a drop would come out. "Curiosity killed the cat..." I wondered what was keeping the water from coming out... I decided to stick a long, small screwdriver in the faucet to see if I could feel it. Anyway... I broke through what was stopping it up... :) Water came shooting out of the valve! Good thing I was in an unfinished basement. I got it shut off, but what a mess! Lesson learned.”

Best drain valve to install if you are replacing the old one

While most water heaters come with plastic valves, you should consider upgrading to a brass ball valve. These valves are stronger and more durable, while plastic drain valves are prone to breaking and clog relatively easily.

The built-in drain should be at least ¾ inch in diameter. It is the standard specification. However, if your drain valve getting clogged every now and then, it might be better you install a ball valve.

You cannot buy a ready-made larger diameter drain valve and fix directly into the water heater because of the outlet hole size. Therefore, you need to assemble a custom made one using a ball valve, a brass nipple and a adaptor to connect the garden hose.

How to keep your drain valves clean and unclogged

After replacing your drain keep it regularly maintained to avoid possible clogging. If you had just replaced the drain valve due to sediment clogging problem, most probably you may have flushed out the tank to remove the sediment collected bottom of the tank.

About one week after replacing the drain valve, drain out your water heater and check the performance. If it drains out with usually good flow, that is a good sign. Check few water samples visually to see if there are any particles. If is so clear just like the water coming out from cold water mains, you don have anything to worry, you can fully drain the water tank once 2-3 times a year. Otherwise, you may have to flush out your water regularly, usually once a month.

Recommended Reading

  1. Water Heater Leaking from the Top? Discover Causes and Solutions for Quick Fixes
  2. Replacing Your Water Heater Expansion Tank: A Step-by-Step Guide
  3. Why does my t&p valve leak
  4. Can Water Heater Expansion Tank Cause a Low Water Pressure
  5. How to replace water heater drain valve without draining
  6. Installing power vent on existing heater - Possible but not recommended
  7. Preventing Water Heater Explosions - Causes, Signs, and Prevention Measures
  8. Choosing the Right Size Water Heater for Your Home - A Calculator Included
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  10. The Ultimate Guide to Atmospheric Gas Water Heaters: Understanding, Maintenance, and Benefits