Danger of Hot Water Heaters Feeding Tempering Valves

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FishScreener

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I need to change some buildings from Single Family Residence, to Bunkhouse Space for Seasonal Employees.

The water heaters are 50-gallon units, and work fine for a family. They run out of water when 8 to 10 seasonal employees come back from a 10-day hitch in the wilderness and all want showers.

Houses with full unfinished basement no issue, just add another water heater, or get a 100-gallon light commercial. On the single stories with mechanical rooms, there isn’t space to upsize the water heater or add another. So, we are discussing adding a tempering valve and setting the thermostats to the maximum.

This means we have a tank with 180-F water, which will cause immediately deep tissue scalds. Which raises alarm bells with the both me and our Safety Officer.

Anyone know of signing, labeling, or plumbing mods to make it less of a hazard?
 

FishScreener

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You need tankless…..
No we don’t. Insufficient power to run them, and Power Co says they don’t have the capacity to upgrade the services to the building. Plus, no local service, and nearly impossible to fully winterize without damage. The Bosch ones I had on the Forest had more repair costs over the first three seasons, than the cost of new units. And the repair parts were long lead items, (three to seven weeks).

When they broke the fourth time, and the repair parts were flat out not available, we went back to tank style heaters. The Maintenance Techs know how to service them, and parts are readily available locally.
 

Twowaxhack

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No we don’t. Insufficient power to run them, and Power Co says they don’t have the capacity to upgrade the services to the building. Plus, no local service, and nearly impossible to fully winterize without damage. The Bosch ones I had on the Forest had more repair costs over the first three seasons, than the cost of new units. And the repair parts were long lead items, (three to seven weeks).

When they broke the fourth time, and the repair parts were flat out not available, we went back to tank style heaters. The Maintenance Techs know how to service them, and parts are readily available locally.
So you don’t have any propane or natural gas ?

So I guess you’re using electric ?

But yeah, you need gas tankless…..you just don’t have the capability. Electric tankless are not something I use or really recommend.
 

Twowaxhack

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I suggest installing your thermostatic mixing valve and install thermostatic/ pressure balanced shower valves if you don’t already have them.

That’s the safest way to do what you want to do.

Keep in mind that you can’t run basic electric tanks that hot. If you try it I assure you that the high limits will be nuisance tripping.

Also when you heat water over 140 you get a lot of mineral precipitation. So your water heater isn’t going to last as long.

The hotter the water the worse it gets. Plan on maintenance.

I have a new old stock Symmons thermostatic mixing valve. It’s the high dollar one they sell.

You want to buy it ? I’ll make a deal on it for you.
 
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Twowaxhack

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It’s in the original box. Has all the paperwork. It comes with extra sleeve orings and a casing gasket.

Looks like it was made in 2006.
 

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Geofd

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That's asymmons master mixing valve, if you gonna use that along with individual shower valves, you would need symmons calculate it for you,we had that style valve but it would over shoot because it could not react in time they will be able to tell you flow rates temp capacities call them and have them help you out before you start piping,make a list of fixtures,heating source,storage capacities,
 

Twowaxhack

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That's asymmons master mixing valve, if you gonna use that along with individual shower valves, you would need symmons calculate it for you,we had that style valve but it would over shoot because it could not react in time they will be able to tell you flow rates temp capacities call them and have them help you out before you start piping,make a list of fixtures,heating source,storage capacities,
They won’t work correctly if subjected to quick changing pressure variations at the Symmons mixing valve.

The 5-200 likes .5 gpm min and 5gpm max. without pressure variations.

A thermostatic shower valve which is pressure balanced will add a safety factor to the user.
 

wpns

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My experience with mixing valves to extend the useful output of a tank is that they work fine when they are running at more than their minimum flow, but just pass the maximum temperature water when used at low flow rates. So taking a shower is fine, but washing your hands may get you the scalding water you are trying to avoid, and the inconsistency is worse than knowing the paradigm that "the hot water is _really_ hot". Your Milage Will Vary, but something to be aware of.
 

Twowaxhack

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I personally would refuse a job like we’re talking about. 👍

One day someone will end up burned. But that’s just one man’s opinion. ✌️
 

Twowaxhack

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With a cold water temp of 35-40 degrees that’s a big factor.



These are meant to be installed on the hot side and only operate when the outlet temp drops below the set point. Setting between 80-140

I’d love to play around with one and install it on the cold water line to a shower faucet faucet set to 80 degrees. Or install it on the cold side feeding the heater and let it run every time you use the hot water. Just to play 🫶


You can call Rheem and they will help you with special situations.
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