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.
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.
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