Installing a hybrid water heater

October 24, 2018 3:16 PM

My Rheem Warrior Glass water heater is giving me water that get colder faster. In anticipation, I bought a A.O Smith 50-gallon hybrid water heater about a month ago. I've watched a lot of YouTube videos and see there are four basic connections on both; hot water out, cold water in, power and pressure valve/drain pipe. The new water heater recommends an expansion tank even though the old one doesn't have one.

The old water heater is connected to the plumbing with flexible compression fittings. Must I change them? The drain pipe is pvc connected to the pressure valve with a different fitting, but not soldered. Can I put the same pvc pipe and fitting on the new compression valve. This looks very simple; turn off power, drain tank, disconnect fittings, remove; move into position, connect fittings, fill tank, turn on power. The installation manual and YouTube both seem to say as much. I've read reviews of installations and they can take hours and cost thousands of dollars. Am I making this too simple?

posted by CollectiveMind to Home & Garden (2 answers total)

I replaced our water heater about 2 weeks ago (previously!).

In theory, yes, it is a straightforward process of pulling out the old tank and swapping in the new one.

In practice:

• Old pipes may be stuck
• There will likely be leaks from the open pipes even after draining the old tank
• You might have a weird constant low flow of water coming out of one of the pipes, even with the valves shut off
• You might not get the pipe connections quite right, meaning you have to either drain the tank several times or just undo the pipe and wait for it to stop spraying
• The new tank will probably be a slightly different height than the old one, meaning you'll need to add new pipes to allow for a proper connection. (Your flexible compression fittings might save the day here.)
• The hardware store will close before you're finished for the day

Having gone through it once I suppose I'd do it again, but I'd block out a full weekend and probably call plumbers first to double check what they'd charge if I can wait a week or two. I can also imagine a newish install being pretty easy to replace when compared to my 20-year-old tank in a 90-year-old house.


I've read reviews of installations and they can take hours and cost thousands of dollars.
When I called around halfway through the job to see what it would cost to have a professional rescue me, everyone ballparked 2-3 hours for a full removal/replacement, and off the top of my head normal rates were a bit under $200/hr.
posted by Nonsteroidal Anti-Inflammatory Drug at 3:38 PM on October 24, 2018

Flexible compression fittings are cheap. Ruined floors are not cheap. The rubber gaskets on the ends of the flexible hoses go bad. I don't think you need to ask how I know this.
And yes to everything said above. Replacing plumbing in older houses seldom goes according to plan. Personal Motto of Plumbing - "It's only ONE MORE trip to the store!"

It looks like your existing water heater is electric. Most of them have two heating elements. Sometimes one of the elements will fracture from repeated hot-cold cycles and stop working. (Again, I don't think you have to ask how I know this.)
This leads of course to less hot water. Changing an element is a 15 minute job tops. If your handy, you could diagnose this with a multimeter by checking resistance (ohms) on the elements. Very high or infinite ohms? No worky. broken.

If not handy, it might be worth your while to have someone knowledgeable come by and have a look. Could save you a bunch of money and heartache.
posted by rudd135 at 6:04 PM on October 24, 2018 [1 favorite]