# Water Heater Mix Valve



## plumbing (Dec 3, 2011)

I have never installed one of these but i would use a socket i have a tool for street main shut off that looks similar. and to get one out you would cut the access out.


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## oh'mike (Sep 18, 2009)

I've never heard of a mixing valve on a water heater----so lets see what that really is---

There are some qualified old pros here-some one will recognize that valve---

Could you take an over all picture of the heater set up?


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## raylo32 (Nov 25, 2006)

I have never seen one either but if you go to Watts or Taco sites they promote these mixing valves as a way to "extend" hot water capacity by allowing you to raise the temp to scalding levels and then it gets mixed down with cold to a safe level to go to the faucets, showers, etc. Since the water in the heater is so hot it takes less water out of the heater to supply a given volume of water at the desired temp. They also say this allows you to safely keep the water heater above 130 which is supposedly the death temp for Legionella bacteria. I know... I have never actually seen one of these in real life, but it does make sense in a way...


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## ben's plumbing (Oct 6, 2011)

thats a scaldguard mixing valve..... is that installed on the out let side of heater.....and does it affect all faucets....


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## VIPlumber (Aug 2, 2010)

> While I've got your ear... This heater and the AC are in the attic above the 2nd story. 20 yrs down the road (hopefully that long) when they go bad, how does one get them out and a new one in? There's a ladder access which is a good size but it's not going to fit an 80gal heater or AC unit up there. Take apart the roof? Take off some siding?:confused1:


Might not be a bad idea to prepare in advance for the day that it needs replacement. Measure up the bigger of the two units and then widen the attic access. Expect to pay a few extra bucks cause the installers are gonna have a hell of a time with the removal and re-install.


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## raylo32 (Nov 25, 2006)

Before recently replacing my water heater I looked into these valves a bit and the other thing I learned is that they come with various maximum high tempertures. For instance, Honeywell (and probably also others) makes one that allows a max of 120 degrees presumably to totally eliminate the chance of scalding. They make other models that will allow setting up a lot higher... but the then the installer has to measure temps from a near faucet and set the valve to the desired temp. And in some communal settings you might worry about tampering and not want valve to be able to go higher than 120... Not the case in a home tho, I would think.

So if you have one of the 120 degree models and a long run of piping to your faucets and showers you may never have truly hot water. Try to determine the valve brand and model. I think the rating of most of them can possibly be identified by the color of the adjuster once you know the brand.

Oof, replacing a water heater in the attic would be a real feat. What were they thinking installing up there? Is space below that tight? Or is this something done in some areas of the country and not others? I've never seen a house built like that.


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## djrussell (Jun 23, 2009)

Thanks for the replies. 

After a looking a little closer and some googling, it appears to be a Cash Acme Heatguard 110D.

It's exactly like the first one on this page. http://www.mmcontrol.com/thermostatic_mixing_valves.php

The Cash Acme site shows an updated version I suppose.
http://www.cashacme.com/prod_thermostatics_HG110D.php

And from the spec sheet



> Unique, purpose designed adjuster tool:





> _Minimizes unauthorized tampering with valve setting._


Would have been nice if someone left that tool for me. The house is built in 09. We're the second owners. I'm still going to try a socket. If that doesn't work, I'll give C.A. a call.

I'll try to reply to all the questions...



plumbing said:


> and to get one out you would cut the access out.


crap 



oh'mike said:


> Could you take an over all picture of the heater set up?


I'll pop up there to snap a pic in the next day or two. 



raylo32 said:


> I have never seen one either but if you go to Watts or Taco sites they promote these mixing valves as a way to "extend" hot water capacity by allowing you to raise the temp to scalding levels and then it gets mixed down with cold to a safe level to go to the faucets, showers, etc. Since the water in the heater is so hot it takes less water out of the heater to supply a given volume of water at the desired temp. They also say this allows you to safely keep the water heater above 130 which is supposedly the death temp for Legionella bacteria. I know... I have never actually seen one of these in real life, but it does make sense in a way...


That all sounds about right. Take a look at the links above.



ben's plumbing said:


> thats a scaldguard mixing valve..... is that installed on the out let side of heater.....and does it affect all faucets....


Yes, it's on the outlet of the water heater. There's one unaffected line that goes to the laundry room for the washing machine. The rest of the hot water for the house goes through this valve.



VIPlumber said:


> Might not be a bad idea to prepare in advance for the day that it needs replacement. Measure up the bigger of the two units and then widen the attic access. Expect to pay a few extra bucks cause the installers are gonna have a hell of a time with the removal and re-install.


I'll keep that in the back of my mind. It's for sure going to be the AC. Maybe I can visit the builder (they still have an office in the neighborhood) and see what they were thinking.



raylo32 said:


> So if you have one of the 120 degree models and a long run of piping to your faucets and showers you may never have truly hot water. Try to determine the valve brand and model.


I do believe it's a 120 degree model. All faucets will eventually get hot water. It takes nearly a full gallon of running to get it at the kitchen sink though. Hopefully this valve still has some adjustment room left in it.



raylo32 said:


> Oof, replacing a water heater in the attic would be a real feat. What were they thinking installing up there? Is space below that tight? Or is this something done in some areas of the country and not others? I've never seen a house built like that.


You got me. There's enough room to install it on the second floor. It's a 2500sqft house in GA (need to update my profile). My parents are in TX and their 2 water heaters are apparently in the attic also. When one goes bad, it just gets uninstalled and pushed to the side.


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## raylo32 (Nov 25, 2006)

You could try a mini vise-grip plier. That should be able to grab that adjuster and turn it w/o buggering it up. But if it is the 120 model it is probably already maxed out.


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## djrussell (Jun 23, 2009)

Here's a slightly better pic. I couldn't hold the camera far enough away to really get everything in view. This is looking down on top of the WH.

A 12mm socket fits nicely on the triangle piece. When I turned it, it started leaking though so I'm thinking that's not the right piece to adjust. I'll get a wrench on the bigger hex piece and see if that's it. I didn't have one with me though. Markings on it indicate as much and which direction to turn for hotter water. I'm not sure why a special tool would be needed.

Does anyone know why that "Apollo" valve is there? It looks like one of these. http://www.apollovalves.com/_products/16-503_504/TS_16-501_3_4.pdf It seems to go to the laundry room.

I measured the AC unit and WH. They'll both JUST BARELY fit through the access. 1/8's of an inch will matter here. Overhead space could be an issue though. I guess they could be lowered down with a pulley or come-along. I'm not looking forward to that day.


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## djrussell (Jun 23, 2009)

djrussell said:


> Does anyone know why that "Apollo" valve is there? It looks like one of these. http://www.apollovalves.com/_products/16-503_504/TS_16-501_3_4.pdf It seems to go to the laundry room.


Y'know, I'll bet that goes right past the laundry room and escapes out the side of the house. There are 2 or 3 hoses out there. I figured one was the TP relief but didn't know what the others were. So this will prevent overpressure to the tank.


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## djrussell (Jun 23, 2009)

For anyone still wondering, turning the hex shaped part on the mixing valve did the trick. I didn't have a socket the right size (it's pretty big) so used some channel locks. Not much force was required so they didn't mar anything. Lefty-Loosy makes it hotter, Right-Tighty makes it colder. 1.5 turns makes a noticeable difference at the faucet. I might even dial it back a little.

Yay hotter water!:thumbsup:


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## Phoebe Ann (Jan 14, 2013)

djrussell said:


> For anyone still wondering, turning the hex shaped part on the mixing valve did the trick. I didn't have a socket the right size (it's pretty big) so used some channel locks. Not much force was required so they didn't mar anything. Lefty-Loosy makes it hotter, Right-Tighty makes it colder. 1.5 turns makes a noticeable difference at the faucet. I might even dial it back a little.
> 
> Yay hotter water!:thumbsup:


What you've done is loosened the fitting holding the adjusting screw (the thing with the triangular head). The effect is the same -- pressure on the internal valve is released -- but if you loosen it enough, it will come out of the valve body and there'll be water everywhere. 1 1/2 turns may allow a small leak, since the O-ring is no longer compressed, so keep an eye on it.


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## asheshp (Nov 20, 2020)

djrussell said:


> For anyone still wondering, turning the hex shaped part on the mixing valve did the trick. I didn't have a socket the right size (it's pretty big) so used some channel locks. Not much force was required so they didn't mar anything. Lefty-Loosy makes it hotter, Right-Tighty makes it colder. 1.5 turns makes a noticeable difference at the faucet. I might even dial it back a little.
> 
> Yay hotter water!👍


I have similar problem, loosening triangle head gave me little leak. How did you fixed that leak? after loosening hex head by 1.5 turn, did problem solved for good?


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## Ghostmaker (Mar 2, 2013)

Ryan homes has been doing this lately.


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