Water heater maintenance

[Chateau_Nomad]

I haven't de-scaled our Dometic "6-gallon" water heater since buying the motorhome new in fall of 2019. We've had fairly light use up until now, and 80% of the water put into the FWT has been from home... save for 6 weeks in Colorado last year.

So I figured it's time. I magically had a pre-made configuration of 1/2" CPVC pipe left from a who knows what project.

It's basically a gravity fill setup threaded into the 1/2" NPT tank drain... where the plastic drain plug goes.

After making SURE the 120v breaker was off, I drained the tank, then opened the low point drains, which aids in getting nearly all water out. Then closed ALL valves in the back of the tank (bypass valves) so nothing could exit the tank.

I installed my gizmo pipe thing, and opened the overflow. I then S.L.O.W.L.Y poured undiluted white vinegar in using a funnel. Note to self... my 6 gallon tank only holds 4 gallons of vinegar...

This will soak overnight. Then drain and thoroughly flush with my handy-dandy tank flush wand I 3-D printed... but Camco has a nice one.

Note... the quarter turn valve is unnecessary. It just happened to be on the pipe.

[ghnl]

I have the Camco version. Seems to work well to flush out the tank.

[16ACE27]

Does a glass-lined water heater really need descaling?

[ghnl]

Not sure about the de-scaling but there was lots of crud when I flushed our water heater's tank. We bought the rig used so it likely had not been done regularly. I flush it out as part of my winterizing procedure.

[Chateau_Nomad]

Originally Posted by 16ACE27

Does a glass-lined water heater really need descaling?

Do any RV water heaters have glass lining? Mine is either aluminum or galvanized steel. I flushed it pretty well before the vinegar and a fair amount of calcium particles came out. We'll see what the vinegar does.

[16ACE27]

Originally Posted by Chateau_Nomad

Do any RV water heaters have glass lining? Mine is either aluminum or galvanized steel. I flushed it pretty well before the vinegar and a fair amount of calcium particles came out. We'll see what the vinegar does.

I believe the Suburban water heaters do.

[Chateau_Nomad]

Update:
Soaked the tank overnight.
Drained vinegar what I could catch) into a bucket.
VERY little amount of deposits came out. However after several sessions of flush/drain I got enough deposits to maybe fill a thimble.

In my case the vinegar was likely overkill. Moving forward I think a thorough flush with water only would suffice.

Of course your results may vary depending on your water source.