Hot Water Mixing Valve

C

Coolbreeze767

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Joined
Sep 3, 2004
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15136
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100
Had an opportunity to help out someone setup an inverter on an RV this weekend and noticed a strange looking valve on the hot water heater, 10 Gallon. Asked him what it was for and he said he could run his hot water heater at 180 degrees and the valve mixed cold water with the hot thus giving him 120 degree water and alot more than just with the standard tank set at 140. Never seen one on a boat to help extend hot water supply but it looked good. Thoughts????????
 
Sure you could do it that way but doesn't your fawcetts do the same thing? Mixing hot with cold water to achieve a desired tempurature.
 
My understanding is it allows you to raise the temp on your hot water heater without the possibility of scalding someone. It makes a smaller hot water tank supply more hot water..
 
I found 'em on Google varying in price from $29 to $99... for the same valve.

As my hot water is solar, I'm gonna look into it.
 
Bill, let me know what you find - the units I've had exposure to, all cost in the $350-$400 range for a single faucet or shower control.
 
Vic,
I have found a Watts 3/4 that mounts on the tank for $40.oo plus shipping. Says it makes a 10 gallon water heater seem like a 16.
 
quote:
Originally posted by Vic Willman

Bill, let me know what you find - the units I've had exposure to, all cost in the $350-$400 range for a single faucet or shower control.

Click to expand...


Point of entry are expensive. The ones at the tank feed the entire house (boat) and are relatively cheap. For a home or a large yacht, they are probably not a good thing; dishwashers, clotheswashers etc... but for a boat like mine, it's worth looking into. That coolant aux heat has bit me more than once.
 
depending on whether this is real fancy otherwise it sounds like a toilet mixing valve. allows you to get warm water in the tank to reduce sweating on the tank. available all over, one mfg: "AMERICAN VALVE Anit-Sweat Tank Valve" $26
 
Vic here's the site; it's called a "tempering valve" but I think it's what you're looking for: LINK
 
My last boat came from the factory with a mixing valve on the HWH. It did make bypassing the HWH for winterizing a little tricky. The mixing valve can be seen in the pic below, along with a bypass kit I made to winterzie.....

100_3460.jpg
 
Dominic, how well does it work? I see the installation doesn't follow the recommendation from Watts that it have an 8"-12" "trapped" area (drop from the output of the water heater). In your opinion, is it worthwhile; or is it just a "gimmick"?
 
Vic....I no longer have that boat. However, when I did have the boat, I always left it in the full HOT position. That may just be because I don't really use my HWH that often. I only used it on trips when I would transient. Hot water conservation was never an issue or something I needed to be concerned with.

Sorry I can't help any further.
 
A mixing valve can also be called a thermostatic valve. they are widely avaialble (thermostatic valve) thru any plumbing supplier for tub & shower valves. you set the temp and it will determine how much cold water to mix at that point to keep the temp constant. both will significantly increase the amount of hot water your tank can produce by letting you use a higher tank temp. the mixing valve set at the heater has the advantage of delievering water cool enough to avoid scalding to the whole system. the thermostatic valve set at the shower allows you to deliever much higher water temps to devices like washing machines and dishwashers. both approaches have their advantages.
 
In addition to increasing my own knowledge, I'm asking for information to try and determine whether or not it would be worthwhile for Raritan to offer the tempering valve as an option.

Watts claims that theirs is not to be used to prevent scalding, so I was trying to determine just what advantages it would offer. If it will indeed increase the amount of hot water available, by allowing the thermostat to be set higher, and then mixing some cold water in with the hot water, to maintain a constant temperature, it could be a definite advantage to the end user.

However, the information available to me from Watts sort of makes a more complicated installation, and I am wondering if the end result is worth the added difficulty in installing it.

I guess that, like most things, there are a number of pros and cons to be considered.
 
Vic:

I think it would be a great addition. If not, the capacity for a DIY kit would be great as well. As I said, I have been bitten more than once by aux heat on both boats I have owned with hot water. Three if you count the USS Boone where the water to the officers showers ran right beside the exhaust stack for the main (jet turbine) engines.
 
mixing the hot/cold water at the tank would provide more hot water at a remote shower/tub than mixing the water at the destination as most hot water lines on boats are not insulated so the temp loss on the water lines would make that solution less efficient. i believe to offer an anti scald valve it must also be pressure balanced and i dont think you can do that if you are only treating the hot water leaving the water heater.
 
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