Help some painters clean their brushes

January 18, 2010 6:34 PM

How do I change the heating element on a small 20 gallon electric water heater if I can't find the drain?

We have a small 20 gallon electric water heater in our painting studio that doesn't work. I tested the cable running to the heater and it has power, which is on it own breaker, and there doesn't seem to be a switch that could be turning off the unit, you can follow the cable right from the water heater to the box.

I bought a cheap continuity tester from Home Depot and it seems the thermostat is OK but the element might be shot. Since it's only ~10 for a 1500W element we'd like to give it try to replacing it, but I can't find a drain on the thing. The feed and return are soldered on, there's the pressure valve but that's near the top of the tank and the element is near the bottom, so I'm guessing that even if I shut the water off to the heater there'd still be a good amount of water in the tank. Some places online said to "just change the element quickly" but that sounds like crazy talk to me because I've never done this before and the heater is soldered into a nest of pipes in a corner, I can just barely access the panel.

Is there something I'm missing? I really looked all around the tank and couldn't find a drain. Can there be a drain on the bottom of the tank? It is resting on a small 2x4 and plywood platform.

posted by JulianDay to home & garden (10 answers total)

Is there a brand on the tank? Any clue as to how old it is?

Also, you noted that it's soldered into the corner ... is it possible that the drain valve is on the back side of the tank? I'm guessing you've felt all the way around the tank already, but I thought I'd ask.
posted by Alt F4 at 6:47 PM on January 18, 2010

I did get all around it and didn't see anything. I did see a brand today but it I can't remember it now, wasn't a big one, it was a three letter acronym like BCR... There was a model number (M2OU5S) but Google gave no results when I looked that up a few days ago.
posted by JulianDay at 6:59 PM on January 18, 2010

Your tank might not have one.

It's pretty easy to change an electric element without draining the tank if you work efficiently. The tank acts like one of those water cooler jugs as long as you shut all the taps off.

1. Have the new element, a few towels, and a folded up hand towel handy.
2. Turn the power to the tank off.
3. Turn off the cold supply tap, you'll probably have to shut off the whole house.
4. Shut off the hot water tap at the tank if it has one.
5. Spread the towels around to soak up spilled water.
6. Unbolt or unscrew the old element using the folded up hand towel to block the hole when you pull the element out. Keep pressure on the towel to stop the water from glugging out.
7. Once you have the new one ready to go in take the hand towel away and slide the new one in.
8. Bolt/fasten as required.
9. Dry the outside of the tank.
10. Turn the supply taps back on. Check for leaks at the element.
11. Run "hot" water in your sink until no air comes out.
12. Only now turn the electricity back on.

posted by Mitheral at 8:18 PM on January 18, 2010

Totally off topic, but I find that using fabric softener works so much better than anything else for cleaning brushes. Pour 4 oz or so into a half gallon or so water and swish it around for a bit. (painter like houses, not like Rembrandt, so YMMV)
posted by KenManiac at 9:38 PM on January 18, 2010

Turn off the water at the street, open a hot tap, slip a hose over a cold tap and initiate a siphon to empty the hot tank backwards via the siphon on the cold tap..
posted by hortense at 11:36 PM on January 18, 2010

open a hot tap to vent the siphon.
posted by hortense at 11:38 PM on January 18, 2010

I was going to suggest what Mitheral wrote. First time I did it I almost crapped with anxiety. It's painless but MAKE SURE all water in and out of the tank is turned off.
posted by From Bklyn at 1:24 AM on January 19, 2010

Thanks everyone. I probably won't get to this for a few days but as always I appreciate the responses. There is a valve just for the hot water heater so at least we don't have to shut off the cold water to the entire floor of the building.
posted by JulianDay at 7:02 AM on January 19, 2010

Seconding the "just turn off all valves and taps, go for it" notion. I am a landlord, we do these at work pretty regularly. Doesn't make much of a mess if you work quickly.
posted by which_chick at 9:03 AM on January 19, 2010

Mitheral's procedure looks good to me, but please add the following step between 3 and 4:

3a)Turn on the hot water at the tap in your sink to relieve the pressure in the tank and hot water lines. When the water stops (or slows to a trickle) you can turn off the hot water tap.

If you don't do this, there's a chance the 60+ psi could shoot the element into your face.
posted by dalesd at 10:11 AM on January 19, 2010 [1 favorite]