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Discussion Starter #1


We have a situation at a Seafood Rest. wherein the hot water tempering valve loads up with white sediment on a regular basis. This is causing the tempering valve to sieze up and not deliver warm water to the rest room lavatories or kitchen hand sinks.

This is a typical large commercial kitchen with a water heating plant delivering 180'F water which is delivered to the commercial dishwasher and also to a tempering valve which mixes it with cold water to make 140'F water for the kitchen sinks and mop sinks. Some of the 140'F water is then further tempered through a second tempering valve to make 110'F warm water for hand washing.

There is a water softener which softens ONLY the water feeding the water heater and the tempering valves to mix with hot water. No soft cold water to anything in the building.

Both tempering valves have extensive sediment build up: However it appears to be only on the hot side.

There is no build up on faucets or the dishwasher.

The "sediment" is a white corrosion LIKE substance.......I say LIKE because it is not corrosion, the bronze valves or piping are not being eaten away, this white stuff is building up on the metalic parts of the devices.

Facts:
1. Softener feeds only the water heaters and the tempering valves.
2. We have checked and the water is soft, also the PH of the water is neutral.
3. On the 140' to 110' tempering valve the cold side is clean and NO build up / hot side siezed up with stuff
4. The "sediment" is building up on the smaller metalic parts. Springs, plungers, gears.....NOT the bronze housings or piping.
5. The water heaters are gas fired....one 100 gallon commercial with a 100 gallon storage tank & one 180' booster heater for the dishwasher.
6. It only takes 4 to 6 months to completely sieze up the entire valving system.

Any thoughts?

Until we resolve this we will be married to a few service calls per year to clean out these valves.. While service calls are good, I'm sure they will tire of the same recurring problem. Would like to have an answer for this client soon
 

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Sounds like scale being formed by calcium particles in the water that bond together when the water is heated. Try installing a sediment filter on the hot side before it goes into the tempering valve.
 

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٩(͡๏̯͡๏)۶&#
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You could also try using one of those electrolysis based de-mineralizers. They work like a water softener accept they use no chemicals and therefore add nothing to the water. They run a DC charge thru a titanium electrode(anode) and the calcium salts in the water become de-ionized after reacting with the anode. The calcium ions are still in the water but since they are no longer charged they will not precipitate out of solution and bond to solid surfaces in hot water systems.

You can get them from Integrity Sales & Marketing, Inc. They are in Mulberry Fl. (863) 425-3900.

I hope that helps.
 

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Professional Bullshioter
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What kind of valve was it?

I knoe Leonard has an extensive maintence plan for their valves. I believe it something crazy like disassembly and cleaning evry 30 or 60 days. I can't recall. They have problems with sediment build-up preventing valve function.
 

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Plumber Manhattan Beach
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828 Posts
We have a situation at a Seafood Rest. wherein the hot water tempering valve loads up with white sediment on a regular basis. This is causing the tempering valve to sieze up and not deliver warm water to the rest room lavatories or kitchen hand sinks.

This is a typical large commercial kitchen with a water heating plant delivering 180'F water which is delivered to the commercial dishwasher and also to a tempering valve which mixes it with cold water to make 140'F water for the kitchen sinks and mop sinks. Some of the 140'F water is then further tempered through a second tempering valve to make 110'F warm water for hand washing.

There is a water softener which softens ONLY the water feeding the water heater and the tempering valves to mix with hot water. No soft cold water to anything in the building.

Both tempering valves have extensive sediment build up: However it appears to be only on the hot side.

There is no build up on faucets or the dishwasher.

The "sediment" is a white corrosion LIKE substance.......I say LIKE because it is not corrosion, the bronze valves or piping are not being eaten away, this white stuff is building up on the metalic parts of the devices.

Facts:
1. Softener feeds only the water heaters and the tempering valves.
2. We have checked and the water is soft, also the PH of the water is neutral.
3. On the 140' to 110' tempering valve the cold side is clean and NO build up / hot side siezed up with stuff
4. The "sediment" is building up on the smaller metalic parts. Springs, plungers, gears.....NOT the bronze housings or piping.
5. The water heaters are gas fired....one 100 gallon commercial with a 100 gallon storage tank & one 180' booster heater for the dishwasher.
6. It only takes 4 to 6 months to completely sieze up the entire valving system.

Any thoughts?

Until we resolve this we will be married to a few service calls per year to clean out these valves.. While service calls are good, I'm sure they will tire of the same recurring problem. Would like to have an answer for this client soon



are you sure it isn't a dip tube? I have had dip tubes do this all the time.
 

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Most commercial water heaters don't have dip tubes, the cold inlet is on the bottom of the tank.
The one I did not long ago you had an option top of side inlet, we connected to top, so it had to have a dip tube in it.
 

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Plumber Manhattan Beach
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The one I did not long ago you had an option top of side inlet, we connected to top, so it had to have a dip tube in it.




Thank you, most commercial water heaters here are piped from the top. There are those that are piped fromt he side, but I mean't one with a dip tube on it.
 

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The one I did not long ago you had an option top of side inlet, we connected to top, so it had to have a dip tube in it.
Thank you, most commercial water heaters here are piped from the top. There are those that are piped fromt he side, but I mean't one with a dip tube on it.

I stand corrected, I have never seen that, perhaps it's a west coast thing. Here if you want a top inlet commercial heater you have to order it, and wait for it to be built.
 

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Chase Plumber
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Sounds like scale being formed by calcium particles in the water that bond together when the water is heated. Try installing a sediment filter on the hot side before it goes into the tempering valve.
I agree with KTS on this.

I had the same trouble at a local jail.

ACORN Recessed Box with Powers 420 and check stops were completely dobbed just about it.

Green scale build-up was the culprit.
 

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Professional Bullshioter
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Speaking of side inlet Wh's. I learned an important lesson as a young journeyman. Put the valves and unions above the top of WH's that are piped tight together in a row.

That way they can be easily removed when the service plumber follows behind.

Don't forget to do the same thing on the gas and pvc intake and exhaust.


We had to change one I had piped a couple years earlier. I had to cut everything to get it out. As well as having to shut the building down to unscrew the gas drop.
 

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WILLPLUMB4$
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584 Posts
We have a situation at a Seafood Rest. wherein the hot water tempering valve loads up with white sediment on a regular basis. This is causing the tempering valve to sieze up and not deliver warm water to the rest room lavatories or kitchen hand sinks.

This is a typical large commercial kitchen with a water heating plant delivering 180'F water which is delivered to the commercial dishwasher and also to a tempering valve which mixes it with cold water to make 140'F water for the kitchen sinks and mop sinks. Some of the 140'F water is then further tempered through a second tempering valve to make 110'F warm water for hand washing.

There is a water softener which softens ONLY the water feeding the water heater and the tempering valves to mix with hot water. No soft cold water to anything in the building.

Both tempering valves have extensive sediment build up: However it appears to be only on the hot side.

There is no build up on faucets or the dishwasher.

The "sediment" is a white corrosion LIKE substance.......I say LIKE because it is not corrosion, the bronze valves or piping are not being eaten away, this white stuff is building up on the metalic parts of the devices.

Facts:
1. Softener feeds only the water heaters and the tempering valves.
2. We have checked and the water is soft, also the PH of the water is neutral.
3. On the 140' to 110' tempering valve the cold side is clean and NO build up / hot side siezed up with stuff
4. The "sediment" is building up on the smaller metalic parts. Springs, plungers, gears.....NOT the bronze housings or piping.
5. The water heaters are gas fired....one 100 gallon commercial with a 100 gallon storage tank & one 180' booster heater for the dishwasher.
6. It only takes 4 to 6 months to completely sieze up the entire valving system.

Any thoughts?

Until we resolve this we will be married to a few service calls per year to clean out these valves.. While service calls are good, I'm sure they will tire of the same recurring problem. Would like to have an answer for this client soon
Why not a repipe?
"T" in and pipe the soft water, currently only feeding the WH to the cold side of the mixing valve..If you add one drop of hard water to soft water you now have hard water. you could also install isolation valves & boiler drains at all 3 pts on the mixing valve, and then using either one of those tankless flush kits or your own home made version to flush out the valve w/ out dissassembly.
 

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Discussion Starter #15
Sounds like scale being formed by calcium particles in the water that bond together when the water is heated. Try installing a sediment filter on the hot side before it goes into the tempering valve.
Good idea... Feed water is 180'F, concerned about comprimising filter housing or element.
 

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WILLPLUMB4$
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Good idea... Feed water is 180'F, concerned about comprimising filter housing or element.
The hotter the water the faster you will draw out the minerals. Is all the water going through the mixing valve being treated? A filter will not do anything for mineral build up, the scale shield may help, but seems to me you already have everything you need on the job right now except pipe. Remeber to K.I.S.S. it, the more you add, the more there is to service/ repair/ replace.
 

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I stand corrected, I have never seen that, perhaps it's a west coast thing. Here if you want a top inlet commercial heater you have to order it, and wait for it to be built.
We have top and dual side down here, You have to buy 4 nipples and 4 caps for whatever side you dont use....
 

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Louisiana Master Plumber
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23 Posts
I Had The Same Problem With A Lenard Valve In A Hospital.
The Build Up Was On The Bi Metal Coil Keeping It From Moving.
I Washed It Out And Reinstalled It, Worked Like New. I Also Had A Water Softener On The 180 Line. The Only Build Up Was In The Bi Metal. I Think The They Should Use A Better Bi Metal. As Was Posted Earlier, Cleaning Every Six Month Will Do The Job.
 
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