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Mobile ViewWATER HEATERS AGE of WATER HEATERS AIRBOUND HEAT SYSTEM REPAIRS ALTERNATIVE HOT WATER SOURCES Electric Shower Heaters High Efficiency Water Heaters Indirect-fired Water Heaters Instantaneous Water Heaters Multiple water heaters in parallel Multiple water heaters in series Range Boiler Water Heaters Side Arm Coil Water Heaters Solar Water Heaters Tankless Coil for Hot Water Tankless Water Heaters ANODES & DIP TUBES on WATER HEATERS ANTI SCALD VALVES APPLIANCE EFFICIENCY RATINGS AQUASTAT CONTROL Functions BACKDRAFTING HEATING EQUIPMENT BACKFLOW PREVENTER VALVE, HEATING SYS BACKFLOW PREVENTER, HEATER WATER FEEDER BACKUP HEAT for HEAT PUMPS BLEVE EXPLOSIONS BOILERS, HEATING CARBON MONOXIDE - CO CHECK VALVES, WATER SUPPLY CHEMICAL CONTAMINANTS in WATER CHIMNEY INSPECTION DIAGNOSIS REPAIR CLOGGED DRAIN DIAGNOSIS & REPAIR CLOGGED SUPPLY PIPING CROSS CONNECTIONS, PLUMBING DEBRIS in WATER SUPPLY, Water Heater DRAIN a WATER HEATER TANK ELECTRIC WATER HEATERS Electric, Gas, Oil Water Heater Efficiency Electric Shower Heaters Electric Water Heater Checklist Electric Water Heater Controls List Electric Water Heater Element Replacement Electric Water Heater Element Tests Electric Water Heater High Temp Cutoff Test Electric Water Heater Repair Guide Electric Water Heater Reset Switch Electric Water Heater Thermostats Electric Water Heater No Hot Water Electric Water Heater Parts Identification Electric Water Heater Reset & Temp Set Hot Water Temperature & Pressure Valve Timers for Electric Water Heaters Water Heater Anode & Dip Tube Check ENERGY SAVINGS in buildings FLOODED HEATING EQUIPMENT REPAIR FLOODED WATER HEATER REPAIR FREEZE-PROOF A BUILDING FROST HEAVES, FOUNDATION, SLAB GALVANIC SCALE & METAL CORROSION GAS BURNER Flame & Noise Defects GAS FIRED WATER HEATERS DRAFT HOODS - gas fired Gas BTUH & Cubic Feet Gas Conversion LP Natural Gas GAS PIPING, VALVES, CONTROLS SOOT on OIL FIRED HEATING EQUIPMENT SPILL SWITCHES - Flue Gas Detection GAS PIPING, VALVES, CONTROLS HEAT TAPES, Heat, Insulation prevent Freeze-Up HEATING COST FUEL & BTU Cost Table HEATING COST SAVINGS METHODS HEATING SYSTEMS HOT WATER SUPPLY HOT WATER IMPROVEMENTS HOT WATER DELIVERY SPEED UP HOT WATER EFFICIENCY IMPROVEMENT HOT WATER PRESSURE EXPANSION RATE HOT WATER PRESSURE LOSS HOT WATER PROBLEM DIAGNOSIS HOT WATER QUANTITY IMPROVEMENT Alternative Hot Water Sources & Methods Anti-Scald Valves & Hot Water Quantity CLOGGED PIPING & Hot Water Flow Extra Tanks to Increase Hot Water Insulate Hot Water Piping Insulate Hot Water Tank? 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This article describes in complete detail the steps in the procedure to remove scale or lime from a hot water heater tank - hot water heater de-scaling or de-liming procedural steps. InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.
The articles at this website will answer most questions about diagnosing and curing noisy domestic water heaters and about the procedure to remove mineral deposits, lime, water scale, silicates, sulfates, aluminates, or silt and sand from a water heater tank. If your hot water source is from a tankless coil, or if you suspect that the clogging problem in your building is in the piping itself, see CLOGGED PIPING & Hot Water Flow. Readers should also see Water Heater Scale Prevention. We suggest you also review WATER HEATER SAFETY. Also see WATER HEATER NOISES and WATER HEATER SAFETY. © Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website. How to Remove Lime or Scale from a Hot Water HeaterLime or scale in plumbing systems is caused by hard water as well as silicates, sulfates, and similar materials form water scale that coats the bottom of a hot water tank or the surface of the electrodes in an electric water heater, interfering with proper water heater operation, causing water heater noises, reduction in hot water quantity, increased water heater operating costs, and a shorter water heater life. Silt and soil debris can also collect in a water heater tank where it can cause similar problems even if the water supply is not hard.
But lime or water scale are more difficult to remove from a water heater: manually scraping the tank bottom through the drain opening or use of a de-limer chemical will be needed. Below we describe these procedures. Readers should also see our discussion of mineral clogging of water piping, water heaters, and tankless coils, organized at HOT WATER IMPROVEMENTS. Other gas fired water heater noises are discussed at Gas Flame & Noise Defects. Why do we need to remove lime or scale from a water heater?At WATER HEATER NOISES we explain how scale in a water heater can reduce the quantity of hot water, reduce water heater life, and cause water heater noises. We explain why it is important to remove the scale from a hot water heater. Step 1: Flush the Hot Water Tank to Remove Silt & DebrisThe first step in curing water heater noises or poor hot water quantity is to turn off and flush out the water heater. See Water Heater Flush Procedure for the full article on the detailed procedure for draining and flushing out water heaters to remove scale, dirt, or debris - a first step in cleaning a water heater to increase hot water quantity, temperature, and water heater life, and to stop water heater noises. Safety Warnings: don't tackle this water heater cleanout project on a Sunday night when you can't call a plumber or buy a replacement part. Water heaters, their heating source (oil or gas burner or electricity or solar hot water), and particularly their relief valves include critical safety components. Do not modify or remove relief valves, chimney connections, draft hoods, etc. as you may create dangerous conditions. Turn off all electrical and or gas power to the water heater and let it cool. Additional tips on draining a water heater tank can be found at ELECTRIC WATER HEATERS Step 2 - Remove Scale Deposits from a Water Heater Tank - Scraping the Bottom of the Hot Water Tank
Safety Warning: never turn on a water heater's heat source before the hot water tank has been re-filled. Otherwise you may damage the heater or create a dangerous condition. Be sure the water heater pressure and temperature relief valve is properly installed and is the proper type. See RELIEF VALVES - TP VALVES. How to Use Scale Removers to Clean a Hot Water Tank or to Clean Scale from the Electric Water Heater Electrodes: Chemical MethodsCurrently there are products such as UN-Lime® (a professional non-muriatic food-grade phosphoric acid based chemical de-limer intended for removing scale from water heaters, recommended by A.O. Smith, available in 1 gal. or 5 gal. containers) or possibly other acid-based products that can dissolve mineral or lime deposits in a hot water tank.
We suggest suggest dislodging as much water heater tank bottom crud as possible, but also taking a gentle approach so as to avoid even the slightest possibility of damage to the tank. If you elect to use a deliming chemical in your hot water tank be sure to follow the manufacturer's instructions, including these general steps:
Delimer disposal note: if the delimer is draining into a sump pit be sure to run enough water to cycle the sump pump several times to flush that component out as well - leaving acid and debris from the hot water cleanout in the sump pump could damage it. Don't Over-Do Acid or Scale Removing ChemicalsIn Krappe's 1940 experiments muriatic acid (HCL) and hexametaphosphate solution were discussed for non-mechanical efforts to reduce or dissolve scale in piping, tankless coils, side-arm heaters, water heaters. The author reported that when the zinc coating is removed by acid (older galvanized steel water heating equipment and tanks), rusty water problems were likely. For this reason, in the 1940's mechanical scale removal was preferred. Modern water heater tanks may be glass lined and less vulnerable to these problems. Muriatic acid is much less harmful to copper-nickel or copper-silicone surfaces than it is to iron and steel, provided it is not left in metal contact longer than necessary to remove the scale. The message: don't over-do it: more and longer is not necessarily "better". How to Remove Lime and Mineral Scale from A Tankless CoilKrappe described using an acid-resistant pump and tubing connected to fittings to circulate an acid-wash through scale-clogged copper piping back in 1940. Plumbers still use this method today. The apparatus must be designed to let the scale particles and gases escape. Plumbers may simply use an acid-proof pony pump and fittings to cycle the acid wash using a plastic bucket as the receiving sump. Watch out: this is a dangerous procedure risking acid burns or other hazards. Don't try this procedure if you are not trained and equipped to do so. See Lime Out / Lime Out Extra, lime remover MSDS, a Summit Brands product. But we have been informed by some plumbers that using acids to clean a tankless coil leave the coil internal surfaces etched and that the result can be faster scale formation than previously. A detailed procedure for cleaning lime and scale clogged tankless coils, also suitable for some other piping and coil type water heaters is found at Clogged Tankless Coil & Hot Water Flow. How to Remove Lime and Mineral Scale from an Electric Water Heater's Heating Electrodes
On some electric water heater models (Rheem for example) the top heating unit is called the "Booster" and operates only during periods of high demand for hot water. Wiring and controls on the water heater may on some models ensure that only one of the heating elements operates at a time. Our photo (left) shows a small electric water heater with two heating electrodes - one is located behind each of the dark access panels on the front of the heater.
This water heater maintenance article series continues at Step 3: Water Heater Scale Prevention. Questions & Answers regarding this articleQuestions & answers about scale and lime formation in water heaters. Ask a Question or Search InspectAPediaHTML Comment Box is loading comments...
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