crawlspacewaterwater-heater
I'm installing a vapour barrier over the dirt floor in my crawlspace. There is a water heater already installed and I'm wondering if it's a good idea to tape the vapour barrier directly to the bottom of the water tank instead of eptying it, disconnecting it, sliding the plastic sheet underneath and putting everything back together. My only real concern is that the moisture under the vapour barrier will cause the base of the tank to rust.
Thanks.
No matter what, it won't explode. Maybe a little bit of splat. But no boom. Ok, really, more of a squishing sound, the sound of your feet splashing through the puddle created when it fails. :)
There may well be an anode, connected to the input line. Or at least there was one, probably corroded away now.
Assuming a little water on the floor won't hurt anything, I would buy an inexpensive alarm that senses the presence of water on the floor. Its just a pair of contacts that set off a battery powered alarm when water bridges the gap. When it goes off, buy a new heater.
If some water in that area will be a problem, then the heater should be in a low pan that will catch a leak. If not, then consider a preemptive replacement, as this heater probably has only a few more years in it anyway.
With brass connected to galvanised pipe you can get some galvanic corrosion. There is something called a dielectic union which I've never needed to use. That may help. You'll need to clean up the rust. That may require cutting out the rusted part or at least scraping it off.
Here's a picture that describes the dielectric union joint.
Best Answer
I wouldn't. You'd essentially be sealing the heater's fate of rust and decay. (See what I did there?)
First, you might find it less painful than you think to get the poly under the heater. A little levering or winching and it'll be off the ground the half inch you need. I'd put your main poly sheet down, then some thin plywood or something to protect it.
You might even take this opportunity to do the annual drain and flush you surely do, making the unit lighter while you lift it.
Otherwise, just cut around the heater. The moisture that gets through that small area probably won't be a big deal.