Vinegar, a Bucket and a Frankenstein Movie

The email landed in early November. Time to flush the water heater.

I already knew. That task had been sitting on my calendar for weeks, staring at me.

This time I wanted to check it off for real. Not pencil whip it.

I’m at 63% task completion for the year. Not a perfect score. Pretty good for an old procrastinator though.

And this task matters more than most. A tankless heater pushes water through tiny little tubes. Hard water leaves minerals behind in those tubes. Skip the flush long enough and they gum up like a coffee maker nobody ever cleaned.

Except this coffee maker costs a few thousand dollars.

So today was the day.

First, tell your calendar what you actually have

This is the part I’m most excited about.

A while back I added my water heater’s make and model to my HomeShape calendar. Navien NPE-240A. Tankless.

That matters. Flushing a tankless unit is a totally different job from draining an old tank. Different valves. Different tools. Different everything.

So when I opened the flush task and tapped “How to,” I didn’t get tank instructions. I got steps for a tankless heater. Like mine.

The flush task on my calendar, written for a tankless unit.

Then I dug out the card that came with my flush kit. Same job. Same order. A couple of small differences, which I’ll get to.

The kit’s own card. Lined up with the calendar almost step for step.

The gear

A few years ago our old tank heater leaked all over the basement. When the Navien went in, I bought a flush kit on Amazon. One like these.

It’s a small submersible pump and two braided hoses. One blue, one red. That’s it.

Here’s the whole list:

• A tankless flush kit (pump + 2 hoses). Shop flush kits
• 2 to 3 gallons of plain white vinegar. I had two spare gallons sitting around.
• A 5-gallon bucket
• Channel-lock pliers. You’ll see why.
• A new inlet filter, if your setup has one
• Towels. Trust me.

Vinegar, bucket, pump, hoses. The whole kit.

The real job: clearing the closet

Our water heater lives in a tiny utility closet off the laundry room. It shares that space with the laundry supplies, a shelf of who-knows-what, and the dog’s dinner station.

The before shot. The heater is in there somewhere.

The dog station is a whole thing. A rubber mat. A no-splash water bowl. An elevated dish stand, because he’s a tall boy. He also sleeps at the other end of the room.

But I digress.

Honestly, moving all that stuff was the biggest part of the job. Once it was cleared, I could finally get to the valves underneath.

Hot valve with the red handle on the left. Cold with the blue handle on the right. Each has a little capped service port.

Hooking it up

Power first. I shut the unit down and unplugged it from the wall. Don’t skip this one.

Then I closed the main hot and cold valves. Or tried to. They hadn’t moved in almost three years and they did not want to start now.

Channel-locks gave me the leverage I needed. Slow and steady. You’re turning a valve, not wrestling it.

Next:

• Caps off both service ports
• Blue hose from the pump to the cold side
• Red hose from the hot side back into the bucket
• Open both service ports

Blue hose on the cold service port. Red goes on the hot side.

That black ring is the whole difference between a clean job and a wet floor.

The hose trick nobody tells you

Two gallons of straight vinegar into the bucket. Pump in. Plug in. Go.

Right away I noticed something. The pump pushes hard enough that the return hose wants to jump out of the bucket.

One unsupervised flop and you’ve got hot vinegar all over the floor.

The fix was simple. I coiled all the extra hose down into the bucket with the pump. The weight holds everything in place.

Extra hose coiled in the bucket. It stays put.

Then I went to lunch (and almost forgot)

The kit says let it circulate for 45 minutes to an hour. So I went upstairs, made a spot of lunch and flipped on the TV.

An old Frankenstein movie was on.

I got sucked in.

A while later it hit me. Oh right. I’m in the middle of a job.

Luckily the pump was still humming along and the hour was about up. No harm done. Frankenstein would have to wait.

Rinse it out

Pump off. Pump out of the bucket. Vinegar down the drain.

While everything was apart, I realized it was the perfect time to swap the inlet filter. I knew I had a spare somewhere.

It took me 30 minutes to find it. Bottom drawer of the dryer stand. Of course it was.

New filter in. Then I moved the red hose over to the floor drain, which was luckily right there.

I opened the cold valve gently. Not full blast. Just enough to push clean water through the heater and out the hose.

Rinse water heading for the floor drain. A bucket works too, just empty it as you go.

I let it run about 5 minutes to push the vinegar out. Then I closed the service ports, pulled the hoses and put the caps back on.

One more rinse

Before opening the hot side back up, I ran to the bathroom next door and turned on the hot tap.

That way any leftover vinegar comes out the closest faucet and goes down the closest drain. Not the kitchen sink. Not the shower upstairs.

Lots of gurgling and bubbling through the heater while that ran. That’s just air working its way out. Normal.

Then:

• Power back on
• Check every fitting for leaks
• Mop up a few small drips
• Put the closet back together

Dog station restored. Dog satisfied.

Calendar vs. kit card

The two sets of steps agreed on the big stuff. They split on a few details:

• Vinegar: The calendar said a 50/50 mix with water. The kit card said straight vinegar. I went straight.
• Circulate: The calendar said 30 to 45 minutes. The kit card said 45 to 60. Frankenstein said about an hour.
• Rinse: The calendar said 15 minutes. The kit card said about 5. I did 5, plus the faucet rinse.

When in doubt, your heater’s manual wins. Navien recommends a flush once a year, and more often if you have hard water.

Here in the Salt Lake valley, that’s us.

The sticker

One last thing. The old service sticker on the side of the heater.

Last flush: 1-24.

January 2024. So much for annually.

So I peeled it off. I don’t need a sticker anymore. The next flush is already on my calendar. So is the next filter.

Sticker gone. Filter swapped. Both live on the calendar now.

HomeShape ROI Table

Spousal Stress Index is not peer-reviewed but is considered highly accurate.

Andrew
HomeShape