adding mixing valve and expansion tank to conventional electric water heater

[Mitchell-DIY-Guy]

Use two 40 electrics or two 50 electrics in series.

Each heater would need 30 amp double pole breaker with 10ga two conductor with ground wire.

This is the most sensible plan. Least costly, readily available, easy replacement when necessary. Listen to the expert.

 

[RustyShackleford]

Use two 40 electrics or two 50 electrics in series.

Each heater would need 30 amp double pole breaker with 10ga two conductor with ground wire.

Or a little 50-amp subpanel (since 2 * (4500watts / 240v) *125% = 47 amps). OTOH, two 10/2 cables is probably less expense and hassle than one 6/2 one; main panel is pretty crowded though.

Seems like series or parallel (for the two water heaters) would both work; why do you prefer series ?

But for now, I'm just going to do the tempering valve with the water heater turned up no higher than 140 degrees, and see if I get complaints about running out of hot water.

 

[Twowaxhack]

Or a little 50-amp subpanel (since 2 * (4500watts / 240v) *125% = 47 amps). OTOH, two 10/2 cables is probably less expense and hassle than one 6/2 one; main panel is pretty crowded though.

Seems like series or parallel (for the two water heaters) would both work; why do you prefer series ?

But for now, I'm just going to do the tempering valve with the water heater turned up no higher than 140 degrees, and see if I get complaints about running out of hot water.

Series is easy for DIY people to properly pipe. You can pipe it in parallel if you’d like. If you decide to pipe in parallel, I suggest using two new heaters exactly the same.
In series it would be easier to use your old heater along with a new one.

I’d use two 30 amp circuits, 10-2 with ground. How you accomplish that is up to you.
I don’t know that you have 240v and some heaters come with 5500 watt elements or they can be installed aftermarket.

I can wire up multiple heaters off one 30 amp circuit but we won’t get into that……..

 

[CT18]

Ok, well seems to be very low mineral content in this water, so hopefully not too bad a problem.

What does the valve do when the calcium builds up ? Pass pure-hot thru, or what ?

Cash Acme tempering valve best I ever installed. Be careful with the one you pictured, it looks like pro press connectors.

 

[RustyShackleford]

Cash Acme tempering valve best I ever installed. Be careful with the one you pictured, it looks like pro press connectors.

No, it's push-to-connect (Sharkbite). But it all comes in pieces, so you can also connect to FNPT. Maybe other options too, with the right tailpiece (I think that's the term).

 

[RustyShackleford]

Use two 40 electrics or two 50 electrics in series.

Each heater would need 30 amp double pole breaker with 10ga two conductor with ground wire.

Another plan might be to run the one 50gal unit in "simultaneous" mode. Would also require another 30amp circuit (or upgrading the existing one to 50amps).

 

[Twowaxhack]

Another plan might be to run the one 50gal unit in "simultaneous" mode. Would also require another 30amp circuit

That would give you faster recovery. It wouldn’t help your standby volume.

2-50 gal heaters would give you a lot of hot water ready to go on demand for back to back showers.

 

[RustyShackleford]

Just came across another wrinkle in this mixing valve decision ... Heard via a local plumber he would not recommend a mixing valve here, saying the town water system uses chloramine in their treatment process and this chemical will ruin the internal workings.

Looked into it a little, and Caleffi claims that their mixing valves have "o-ring seals made from durable peroxide-cured EPDM" which "resist wear from common water treatment additives such as chlorine and chloramines".

So I wonder if some of the failures people talk about are due to this issue. And if Caleffi is the only manufacturer to address it, or if they're just the only one to talk about it. Thoughts ?

 

[Geofd]

No I'm sure mixing valve co think about water quality, we have a couple different mixing valves in our buildings some all brass some with a mix of brass and o-rings
We clean ours with vinegar, water quality and the protection of mechanical equipment is the owners responsibility filter systems, water softeners, and preventive maintenance j

 

[RustyShackleford]

No I'm sure mixing valve co think about water quality, we have a couple different mixing valves in our buildings some all brass some with a mix of brass and o-rings
We clean ours with vinegar, water quality and the protection of mechanical equipment is the owners responsibility filter systems, water softeners, and preventive maintenance j

Ok, well maybe this plumber is wrong ? I guess I'd try to call Residio and ask if their o-rings are "peroxide cured". Looking into it a bit more, it looks like the alternative is "sulfur cured", which presumably isn't as good.

 

[Mitchell-DIY-Guy]

Don't know why these manufacturers try to save a few pennies. They should be using Viton instead of EPDM for O-rings. If the part was a $2.00 valve, yeah maybe EPDM. But a Caleffi mixing valve? They ought to know better.

 

[RustyShackleford]

Followup from plumber friend ...
It's not the o-rings that are the problem. The chloramine directly attacks the brass out of which the components are made. It deposits calcium, which messes up the device's innards. With mixing valves, takes about a year. Then, a secondary reaction under the deposit leaches out the zinc from the brass, leaving a water permeable copper matrix that's quite brittle and subject to catastrophic failure depending on where the dezincification takes place. I talked to engineering at Webstone, and they said that taking the lead out per code requirements for domestic water components probably exacerbated the problem.

 

[Twowaxhack]

Yeah, lead free brass sucks.

I don’t have a problem using leaded valves and fittings at my home, I don’t drink tap water. Honestly I don’t know anyone who does.

 

[Mitchell-DIY-Guy]

So let me get this straight. A well known manufacturer of brass plumbing parts blames either the use of Chloramines (used for eons which help ensure most domestically supplied water in the USA is potable out of the tap) -OR- the reduction of lead mandate in brass used for potable water fittings as a factor in failure cause of their products?

Sounds like instead of whining or complaining they need to send their engineers back to the drawing board.

This reminds me of some automotive companies whining and complaining about how 10% ethanol causes all kinds of fuel system problems. Meanwhile at another manufacturer and even at another product team at the complainer, they have perfectly functioning FlexFuel vehicles that happily drink E85, 85% ethanol…without system failures.

Some manufacturers need to stop trying to assign blame and instead design for their present environment.

 

[Twowaxhack]

So let me get this straight. A well known manufacturer of brass plumbing parts blames either the use of Chloramines (used for eons which help ensure most domestically supplied water in the USA is potable out of the tap) -OR- the reduction of lead mandate in brass used for potable water fittings as a factor in failure cause of their products?

Sounds like instead of whining or complaining they need to send their engineers back to the drawing board.

This reminds me of some automotive companies whining and complaining about how 10% ethanol causes all kinds of fuel system problems. Meanwhile at another manufacturer and even at another product team at the complainer, they have perfectly functioning FlexFuel vehicles that happily drink E85, 85% ethanol…without system failures.

Some manufacturers need to stop trying to assign blame and instead design for their present environment.

Water quality and treatment varies all over the US.

It’s up to the customer and their plumber to decide upon what materials are used and a plan of action to protect those materials from local water conditions and other install conditions.

 

[Mitchell-DIY-Guy]

That may be true. But if you make a part that is not going to play in Peoria, but will work in Paducah, time to rethink your efficiency and engineering. The way that water is sanitized is not new. The chloramines have been used since the 1930s. Time to wake up and smell the coffee.

As for water quality, the EPA sets standards that must be met for municipal water systems. So design your parts to work with those standards including sanitizing compounds. If you cannot do that time to think about what business you are in. Anyone can make crappy parts that fail.

Last time I checked most plumbers (and most homeowners) don't have degrees in metallurgy, so thinking the plumber and homeowner can do testing on brass components to see if they'll work in their application is nonsense.

For a manufacturer to blame failure because of chloramines in water is just passing the buck on their own poor standards.

 

[Twowaxhack]

That may be true. But if you make a part that is not going to play in Peoria, but will work in Paducah, time to rethink your efficiency and engineering. The way that water is sanitized is not new. The chloramines have been used since the 1930s. Time to wake up and smell the coffee.

As for water quality, the EPA sets standards that must be met for municipal water systems. So design your parts to work with those standards including sanitizing compounds. If you cannot do that time to think about what business you are in. Anyone can make crappy parts that fail.

Last time I checked most plumbers (and most homeowners) don't have degrees in metallurgy, so thinking the plumber and homeowner can do testing on brass components to see if they'll work in their application is nonsense.

For a manufacturer to blame failure because of chloramines in water is just passing the buck on their own poor standards.

That’s the way you’d like it to be, that’s not how it is.

It’s part of most plumbing codes to make sure the piping and fittings are compatible with the water.

The customer is also responsible because water conditions can change.

Sorry, it’s true. Read the fine print on any pipe/fitting warranty, water quality is addressed.