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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 PREVENTERS BACKUP HEAT for HEAT PUMPS BLEVE EXPLOSIONS BOILERS, HEATING CARBON MONOXIDE - CO CHECK VALVES CHEMICAL CONTAMINANTS in WATER CHIMNEY INSPECTION 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 PRESSURE EXPANSION RATE HOT WATER PRESSURE LOSS 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? Larger Diameter Water Supply Piping Water pipe clog diagnosis Water pipe clog repair guide HYDROGEN SULFIDE GAS INDIRECT FIRED WATER HEATERS MANUALS & PARTS GUIDES - HVAC MIXING / ANTI-SCALD VALVES NO HEAT - NO HOT WATER: HEATER DIAGNOSIS NOISE / SOUND DIAGNOSIS & CURE NOISE CONTROL for HEATING SYSTEMS NOISE, PLUMBING CHECKLIST NOISES, WATER HEATER ODORS & SMELLS DIAGNOSIS & CURE ODORS GASES SMELLS, DIAGNOSIS & CURE ODORS IN WATER OIL FIRED WATER HEATERS PIPING IN buildings, Clogs Leaks Types PLASTIC HEATER VENT RADIANT HEAT RANGE BOILERS RELIEF VALVES - TP Valves on Boilers RELIEF VALVES - Water Heaters RELIEF VALVES - Water Tanks SAFETY, HEATING INSPECTION SCALE REMOVAL, WATER HEATERS SEWER GAS ODORS SOLAR ENERGY SYSTEMS SOLAR HOT WATER HEATERS SOOT on OIL FIRED HEATING EQUIPMENT SPILL SWITCHES - Flue Gas Detection TANKLESS COILS AQUASTAT CONTROL Functions Clogged Pipes / Tankless Coil De-Scale MIXING / ANTI-SCALD VALVES Tankless Coil Conversions Tankless Coil Leaks Tankless Coil Hot Water Increase TANKLESS WATER HEATERS Electric Shower Heaters Guide to Tankless Water Heaters Operation & Characteristics Problems & Defects Hot Water Delivery Speedup Installation Requirements & Costs Should I Convert to a Tankless Heater? Calculate Water Heater Requirements Capacities of Tankless Water Heaters Life Expectancy & Applications Temperature Pressure Relief Valves - Water Heaters THERMOSTATS, HEATING / COOLING THERMOSTATS, WATER HEATER AQUASTAT CONTROL Functions Electric Water Heater Thermostats TIMERS for ELECTRIC WATER HEATERS VALVES, PLUMBING WATER CONTAMINANT LEVELS WATER HAMMER NOISE DIAGNOSE & CURE WATER HEATERS WATER HEATER ALTERNATIVES WATER HEATER ANODES, DIP TUBES WATER HEATER AIR INLET WATER HEATER DEBRIS FLUSH WATER HEATER DRAIN PROCEDURE WATER HEATER FLUSH PROCEDURE WATER HEATER NOISES WATER HEATER PROPERTIES Electric, Gas, Oil Water Heater Efficiency Water Heater Life Expectancy Comparisons Water Heater Operating Cost Comparisons Water Heater Purchase & Maintenance Costs Water Heater Water Quantity Comparisons Water Heater Recovery Speed Comparisons Water Heater Safety Comparisons WATER HEATER SCALE - De-Liming Procedure WATER HEATER SCALE PREVENTION WATER HEATER SAFETY WATER HEATERS for HOME HEATING USE? WATER ODORS, CAUSE CURE WATER PIPES, Clogs Leaks Types WATER PRESSURE & FLOW MEASUREMENT WATER PRESSURE VARIATION CAUSES WATER PRESSURE TOO HIGH: DANGERS Definition of Static Water Pressure Definition of Dynamic Water Pressure Measure Municipal Water Pressure Measure Pump & Well Water Pressure WATER FLOW RATE MEASUREMENT HOT WATER PRESSURE EXPANSION RATE WATER PRESSURE GAUGE ACCURACY WATER PRESSURE LOSS DIAGNOSIS & REPAIR WATER PRESSURE REDUCER / REGULATOR WATER PRESSURE REPAIR GUIDE - WELLS WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS WATER PUMPS & WELLS WATER PURIFIERS WATER QUALITY TESTS, CONTAMINANTS, TREATMENT WATER QUANTITY IMPROVEMENT WATER SOFTENERS & CONDITIONERS WINTERIZE A BUILDING More Information |
This article explains the hot water heating capacity of tankless water heaters, also called instant water heaters or "on demand" water heaters. The quantity hot water is delivered can be expressed in gallons per minute of hot water at a particular temperature rise over the incoming water temperature. We also discuss the question of what "endless hot water" really means. Page top sketch of a point of use tankless water heater courtesy of Carson Dunlop. Also see tankless water heater Problems & Defects where we describe the Tankless Water Heater Cold Water Sandwich Effect. Readers should also see ALTERNATIVE HOT WATER SOURCES to distinguish among these types of hot water producing systems. The original text of this article was provided courtesy of Carson Dunlop - that text has been edited and may not entirely reflect CD's views. Our OPINION is that readers looking for plenty of hot water heated efficiently should also consider the heater we describe at Indirect-fired Water Heaters. © Copyright 2010 InspectAPedia.com & Carson Dunlop Associates, 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. Typical Tankless Water Heater CapacitiesA typical small point of use electric tankless water heater may be able to increase incoming water temperature by about
A larger electric tankless water heater may be able to increase incoming water temperature by about
Some tankless water heaters are rated at 9.8 GPM but be sure to check the temperature rise that the heater can provide at that flow rate (35 deg.F.). We haven't seen a tankless water heater providing more than 5 gpm flow rate at high temperature rise (over 65 degF) rating. If your building needs higher hot water flow rates you may need to use a conventional hot water tank or a gang of tankless water heaters. If you're trying to provide 100° water, a 35 deg.F. temperature rise assumes an inlet water temperature of 65°F - not something you can count on in cold climates. In our OPINION, even 100° temperature rise may not be high enough if the system is being used with a mixing valve or on long piping runs that we described earlier. Does a Tankless Water Heater Provide Endless Hot Water?Well yes, no, and sort-of. Limitations on Hot Water Production Rate of Tankless Water HeatersEach model of tankless water heater is rated to provide a specific water temperature rise, for a given water flow rate. Typically a tankless water heater can provide 2 – 5 gallons (7.6 – 15.2 liters) of hot water per minute. For example, a heater may be capable of increasing the temperature of incoming water 60 deg. F. at 3 gallons per minute flow rate. The temperature rise that a tankless water heater can provide and the water flow rate that it can support depend on the heater's BTU output capacity which in turn is a function of the fuel used (gas-fired or electric) and the efficiency and the size of the heater. Questions & Answers regarding this article. Ask a Question or Search InspectAPediaHTML Comment Box is loading comments...
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