New Hybrid Water Heater Install

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MTy

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I was able to snag a 65 Gallon Rheem Hybrid heater for $400 off. It is being delivered in a couple of days. I taught myself to sweat copper when doing my master bath reno but because I've never installed a water heater I want to make sure I am doing things right and there isn't something I am overlooking.

1. Below is my plan for running the lines to the heater. My cold and hot come out of the attic floor and connect into the top of the current heater. I plan to use a mixing valve so I can set my heater temp at 140 and temper to 120.

I have decided not to add an expansion tank at this time, despite it being in my drawing. It is not required by code for open systems, as in my case and it is another failure point. I will install a shutoff ball valve on the cold side and leave enough space so one can be installed in the future, if needed.

That being said are their any issues with my plan so far?

2. The instructions call for a minimum 6 inch heat trap. Based on my understanding from reading here on how heat traps work and are designed, could the fact that my pipes drop down from my attic at least 6 feet before any branches serve as a "built-in" heat trap?

or do I need to run the pipes up from the heater intake and then back down? Does having a mixing valve in the mix (no pun intended) change things?

3. Connections to the heater: I don't know what types of connections it comes with but based on what I have read here it would be preferred to use 6-8 inch brass nipples instead of dielectric nipples and connect threaded copper that I can then sweat my 3/4 copper to. Sound right? Local code requires rigid connections so no corrugated copper.

I'll be tying the condensate drain line into the drain line for my drain pan just before it daylights for now. Sometime in the spring I'll run it to my first floor washer standpipe when I open up the wall to replace the washer shutoffs.

Anything I am missing?

mty-01.jpg
 

Tuttles Revenge

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Looks good to me. I think the heat trap is a good idea in your setup to prevent heat from travelling up to the mixing valve.
 

wwhitney

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What's the dogleg on the cold line for? And is there really enough room below the cold water inlet on the tank for an expansion tank? I would think you'd want the provision for an expansion tank to point up?

If you move the mixing valve down near the cold water inlet, you have less piping overall, and I think that drop would suffice as a heat trap.

Cheers, Wayne
 

MTy

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The dog leg is the heat trap although I don't know if it needs to be horseshoe shaped or just drop. But if it should go before the mixer it will likely have to be like that.

Probably not enough room which is why I'd turn the expansion tank upside down if I was installing one. But for the reasons in the first post I'm going to leave room to install one in the future if it becomes needed. Good idea on the mixing valve.

The vibration isolation kit is a racket at 150. Any reason I can't buy square isolation pads and put them in the same location as the ones from the kit?
 

wwhitney

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Does a cold water inlet at the bottom of a tank need a heat trap? I would have thought only the hot water outlet needs one.

Cheers, Wayne
 

MTy

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Does a cold water inlet at the bottom of a tank need a heat trap? I would have thought only the hot water outlet needs one.

Cheers, Wayne

Dunno. Based on the installation instructions page 8 it's supposed to go on the cold line. https://www.manualshelf.com/manual/rheem/xe65t10hd50u1/instructions-assembly-english/page-8.html

My understanding of the heat trap was to prevent backwash of hot water into the cold supply, so the trap would need to be on the cold. https://www.waterheaterhub.com/water-heater-heat-traps/
 

wwhitney

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Hot water certainly rises. The question is whether in a closed system (no loop) the heat transfer rate downward through a vertical pipe is slower than it is laterally through a horizontal pipe. Apparently the Rheem manual advice is based on that idea, and so they show the heat trap on the cold side.

Cheers, Wayne
 

MTy

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Received and unboxed the water heater today. Boy this thing is going to be fun to get up to the attic. At least it's all stairs and no ceiling access. Got to grab a couple of friends and an appliance dolly.

Anywho, I was expecting a bit different for the cold and hot connections having never installed a heater before. Instead of holes it has two nipples. Hot is stainless and appears to have a plastic lining.

Cold is the same but also has a brass fitting connected to the nipple with the auto shutoff on it. What's the best way to connect these to my thread copper sweat fitting? Directly? Using a brass coupling and fitting first?

Do they make brass nipples with a female end?
 

wwhitney

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I would typically use a copper threaded fitting directly onto the threaded nipples from the water heater, but sweat all the connections within 6-12" of the threaded connection first, then make up the threaded connection. Just an amateur, not sure if there's a better approach.

Not sure why you'd want a brass nipple with a female end in this context. They exist for very short lengths in 1/2" and maybe 3/4", where a close nipple and a coupling would be too long. Anything longer and you just use a nipple and a coupling.

Cheers, Wayne
 

MTy

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I'm probably overthinking this but was reading about dielectric unions and preventing galvanic corrosion. Had seen some suggestions here recommending long brass nipples instead of dielectric unions.

However, this article seems to indicate there would be little to no difference between the use of copper or brass in preventing corrosion. https://structx.com/Material_Properties_001.html

Simplest thing would definitely be to sweat all the needed fittings then just screw the copper unions on.
 

Dana

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Looking for trouble where none might exist...

Rheems only operate in environments between 37F and 145F. In winter the heat pump is going to pull heat from the attic air, lowering the temperature of the attic a degree or three (depending on the volume of the attic space. In summer it will also cool the attic a bit, but it won't be cooling very much when the attic air temps are above the storage temp.

Are you dead-sure your attic never drops below 40F in winter or rises above 145F in summer?
 

Jeff H Young

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Its a little expense but a brass union (or a coupling) then a 6 inch brass nipple then a copper female adapter is a common way. Some guys put a female adapter directly on the water heater nipple but I don't recommend that. The union is preferred and code says it should have one, supposed to have union on T&P relief as well but I don't see 1 in 20 that put a union there. supposedly you can change a water heater without making changes cutting the copper or soldering just unscrew connections in a perfect world
 

MTy

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Looking for trouble where none might exist...

Rheems only operate in environments between 37F and 145F. In winter the heat pump is going to pull heat from the attic air, lowering the temperature of the attic a degree or three (depending on the volume of the attic space. In summer it will also cool the attic a bit, but it won't be cooling very much when the attic air temps are above the storage temp.

Are you dead-sure your attic never drops below 40F in winter or rises above 145F in summer?

Dead sure on the 145. Been planning this since the summer and put a thermometer in the attic on a couple of days were it gets about as hot as it will in my area. 120 Max ambient. 130 surface ontop of the current heater.

It gets below 40 but not often enough or for long enough periods of time to negate the efficiency gains the rest of the time.

Last Q for now. How do you pros get the thing into drain pans? Code requires a 6 inches walled one. I think building a ramp or s series of platforms the thing can be rocked onto. I'll have help but not enough for a dead lift.
 

Reach4

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MTy

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Its a little expense but a brass union (or a coupling) then a 6 inch brass nipple then a copper female adapter is a common way. Some guys put a female adapter directly on the water heater nipple but I don't recommend that. The union is preferred and code says it should have one, supposed to have union on T&P relief as well but I don't see 1 in 20 that put a union there. supposedly you can change a water heater without making changes cutting the copper or soldering just unscrew connections in a perfect world

The water heater itself was expensive. I'm in this far, might as well do it right.


Thanks for the suggestion. Unfortunately that handle thing won't work because the water connections are on the side.

I'm thinking at this point the best way is to use the pallet it was delivered on as one platform build and screw a second one a bit higher than the pan into the attic floor then rock the heater onto those then into the pan.

Any reason I can't put 4-6 of these https://www.supplyhouse.com/DiversiTech-MP-6E-E-V-A-Anti-Vibration-Pad-6-x-6-x-7-8
Underneath the heater in lieu of the official vibration isolation kit? $160 for the kit is a bit ridiculous.
 

wwhitney

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How do you pros get the thing into drain pans? Code requires a 6 inches walled one.
I'm seeing only 1.5" of depth required:

https://up.codes/viewer/tennessee/ipc-2012/chapter/5/water-heaters#504.7

If you have enough muscle to tip it on an edge, you could slide a 2x4 (or thicker if necessary) under one side, then screw the 2x4 down. Then you could tip the other edge up and slip in another 2x4, a bit farther under. Then slide the pan edge under it and put a 2x4 inside the pan under the edge of the water heater. Then maybe twirl the water heater around into the pan?

Cheers, Wayne
 

MTy

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I'm seeing only 1.5" of depth required:

https://up.codes/viewer/tennessee/ipc-2012/chapter/5/water-heaters#504.7

If you have enough muscle to tip it on an edge, you could slide a 2x4 (or thicker if necessary) under one side, then screw the 2x4 down. Then you could tip the other edge up and slip in another 2x4, a bit farther under. Then slide the pan edge under it and put a 2x4 inside the pan under the edge of the water heater. Then maybe twirl the water heater around into the pan?

Cheers, Wayne

Local amendment requires 6 inch for attic instillations.

That's not a bad idea at all.
 

Reach4

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Code where I am requires a vacuum relief valve on a bottom fed water heater. You should check into that.
Vacuum relief on an attic-mounted WH makes sense to me.

MTy, will the WH travel to the attic upright, or will it be tilted up upon arrival?
 
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