Water Heater Replacement Question

[Gunfixr]

I think this will be the first thread i've started here, lol.
Going to be replacing the existing electric water heater. I've helped friends by doing this, so it isn't my first rodeo, but I have something a bit different here.
Current heater is 13yr old whirlpool. It is in a sort of "closet" off the utility room. There is a crawlspace underneath. It is not in a pan, but directly on the floor. The electric line comes up out of the floor, and there is a newer line that comes off the heater, and in midair, they are spliced together with wire nuts and tape. Two white pex lines come up through the floor and connect straight to the input and outputs of the heater, via what appears to be something like a compression fitting, a nut that is just tightened down. The t/P valve has a pex line that goes down the side and through the floor.

I plan to change the wiring setup by mounting a Junction box on the wall next to the heater, running the feeder line into it, and running a line from the heater into the Junction box for the connection. It will have a lid mounted.

I plan to add a pan underneath the new heater.

The new heater is the same size as the old, I already have purchased it. I have purchased the new unit in accordance with the circuit (20 amp, with awg 12, new unit is 4500kw elements).

So, my questions:

Is running pex directly to the heater's in and out hookups acceptable? I was under the impression that some sort of insulator section was required (i've always worked on units involving copper or steel piping).

When installing the pan, can I use a t-fitting off the pan, and end the t/P valve line into the top of it, using one line through the floor, or would it be better to end the t/P valve line inside the pan?

 

[nadogail]

Using PEX only should be OK, Because the PEX is, I believe, a non conductor and so a separate Dielectric union would be redundant.

Your local building department can address the issue of relief valve plumbing.

 

[u2slow]

4500W works out to 18.75A. In most cases its only permissible to load a 20A circuit to 80% (16A).

You may require a larger circuit... depends on your Code and local ammendments.

 

[Jim greengo]

I normally use 10/2 for water heaters,a disconnect would be a good idea also if it's in a closet.
Dont forget a shut off on cold water side,I prefer copper but use what you like.

 

[drivesitfar]

I just installed a gas hot water heater last year and since I have copper I thought I needed a dielectric union, but the GCV failed and I had to replace the heater 6 months later. when I removed the 6 month old dielectric unions they were as bad as i've seen any in galvanized pipes I've replaced.

my issue was the Rheem tank I bought had a dielectric union already installed on the ******* that looked like they were stainless or galvanized pipe (it had a plastic liner) so when i re installed the new tank I currently have I eliminated the unions.

so you might want to find out if you have yours already installed if that's one of your questions and i'm here to learn how PEX differs cause i'm sure one day they will quit making copper pipe and i'll have to buy and use PEX.

good luck!!

 

[Krfjkm]

Just installed one myself— check to see if you need an anti siphon valve/ vacuum breaker and an expansion tank. I also used the water heater lines sold at Home Depot.


Sent from my iPhone using The Garage Journal mobile app

 

[Gunfixr]

The cold line has a shutoff valve, I forgot to mention that.

On the electrical disconnect, I thought about that. The closet has the furnace on the left, and the heater on the right. A door is in front of the furnace. There is removable panel in front of the heater, and the washing machine is in front of the panel. The electric line comes up out of the floor in the far right corner. I'd have to put the disconnect on the left side to reach it. The house main breaker box is on the other side of room, 8-10 ft away.

I'm in VA, i've yet to see an expansion tank on a water heater anywhere, city or well. We are on a well and septic.

I'll look at the electric line. The feeder piece is different than the tie-in piece, which is newer. I couldn't read the older piece, and wasn't moving all that stuff just to make this post. The shorter tie-in piece is 12 GA. Hopefully, the feeder is 10, and I will definitely tie it in with 10.

 

[Gunfixr]

So, i'm finally getting around to doing this, life, you know how it is.
Pulling the old one, it's unhooked electrically (yes, I turned off the breaker and verified first), water lines loose, waiting on it to drain.
The house line is also 12ga, consistent with the 20a breaker. After this thread, one day when I heard it running, I touched the line, it was warm. Now, pulling the unit, I can see and read the label, it has 4500kw elements, provided they are factory size.
All my online research says 30a for 4500kw, 20a will suffice for 3500kw.
Because of the breaker, and my suspicion that I might find the house line to be 12ga, I had purchased a unit with 3500kw elements.
Glad I did that.
The old one has been there 13yrs, a wonder there was no issues........

 

[drivesitfar]

what is the question or just posting to tell us what you found? I'd say your 12 gauge wire was a bit on the skinny side and it still might be depending on how long the run is even with the lower KW heater. good luck and hope the new one with less KW does the job.

 

[metlmunchr]

The old one has been there 13yrs, a wonder there was no issues........

I gave up on trying to even guess how long a water heater might last.

The original one in my house lasted from 1974 to 2000. The replacement is still chugging right along after 20+ years.

I sweated in the connections on one for a neighbor across the street a couple years ago, and he mentioned that was his third one in 25 years.

My dad built his house in 61. Heater replaced once between that time and 2000. Gas company ran a line up his street in 2000 and he replaced the still working heater with a gas one then to get the year around rate on gas use. That one is now 20+ and still good.

BUT, my sister and BIL live a block from Dad, on the same city water line. Been there 35 years, and they've never had a heater last more than 7 years.

 

[Gunfixr]

It wasn't a question, more of a heads up.
But, there was a problem. While I supposedly bought one with 3500kw elements, and was told I did, when I rolled it into the kitchen and looked at the sticker, lo and behold, it said 4500kw elements.
So, I ran a quick 30a circuit. 10awg romex, 30a breaker. It's not perfect, part is through the room, without conduit, but at least it won't burn up. It's up at the ceiling, almost 9ft, so nothing should happen to it.

 

[nadogail]

I have become very fond of the Flex Hoses with Sharkbyte connections for the water heaters I replace at my rental properties. Been using Shark Bytes for 20 years with no problems.

 

[Jeepster04]

If you can easily replace the wiring, it sounds like its in need of replacement anyway since you have a splice just taped up in midair. Thats a no no...

Im a fan of having an expansion **** on the water heater.

 

[larry4406]

If you can easily replace the wiring, it sounds like its in need of replacement anyway since you have a splice just taped up in midair. Thats a no no...

Im a fan of having an expansion **** on the water heater.

Op is on a well so his house has a bladder expansion tank already so no need for another.

Lastly - the expansion tank requirement really depends on your type of water service. Well - not needed as the well system normally includes a bladder expansion tank. Municipal service with backflow as part of water meter - needed. Old style municipal service without a back flow - check with your AHJ as these types normally let the the expanded house water system "push" against the main.

New construction in 2 counties recently - one in MD with backflows (WSSC) thus expansion tank required. Fairfax County - no backflows and no expansion tank.

 

[finn]

Not sure about no expansion tank needed just because you have a well / bladder tank system in your house.

I don’t have a (redundant) evpansion tank in my house, but there is a shutoff valve in the supply system at the inlet to the water heater. In the unlikely event that valve was shut off and there was a tank thermostat malfunction, the release valve is all that’s protecting from over pressure.

Unlikely, for sure, but in the interest of streamlining the codes, I can see why the code writers would make an expansion tank mandatory with any water heater installation, either well or city water supply.

Like I said, I am on a well and don’t have the redundancy, but I don’t loose sleep over it either.

 

[Gunfixr]

If you can easily replace the wiring, it sounds like its in need of replacement anyway since you have a splice just taped up in midair. Thats a no no...

Im a fan of having an expansion **** on the water heater.

Since I ended up running a new circuit, I deleted the midair connection. One piece of wire directly from the breaker to the heater connection.

 

[Jeepster04]

Since I ended up running a new circuit, I deleted the midair connection. One piece of wire directly from the breaker to the heater connection.

Good deal, I missed your post where you said you ran a new wire.

About the watts, did you check to see if it was a dual wattage element? Sometimes they have a tab you can snap off to get the full 4500 watts, otherwise its a lower wattage (3500 I guess).

I would still want a bladder on my water heater, even if if I was on a well or my house didn't have a check valve. Just make sure the bladder tank on the water heater is above the pressure that the pump shuts off at. For example, my house has around 60psi, I keep 80psi in my bladder tank.