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 Mobile ViewPLUMBING SYSTEM INSPECT DIAGNOSE REPAIR AGE of PLUMBING MATERIALS & FIXTURES AIR DISCHARGE at FAUCETS, FIXTURES AIR INLET VALVE, WATER TANK AIR VOLUME CONTROLS, WATER TANK ANTI-SCALD VALVES BACKDRAFTING HEATING EQUIPMENT BATH & KITCHEN DESIGN GUIDE BLEVE EXPLOSIONS BLOCKED DRAIN REPAIR METHODS BOILERS, HEATING BUILDING SAFETY HAZARDS GUIDE CHECK VALVES, WATER SUPPLY CLOGGED DRAIN DIAGNOSIS & REPAIR CLOGGED SUPPLY PIPING CROSS CONNECTIONS, PLUMBING DEBRIS in WATER SUPPLY, Water Heater DRAIN a WATER HEATER TANK FILTERS, WATER Water Heater Anode & Dip Tube Check FLOODED HEATING EQUIPMENT REPAIR FLOODED SEPTIC SYSTEMS, REPAIR FLOODED WATER HEATER REPAIR FLUSHOMETER VALVES for TOILETS URINALS GALVANIC SCALE & METAL CORROSION GAS BURNER Flame & Noise Defects GAS FIRED WATER HEATERS GAS PIPING, VALVES, CONTROLS GALVANIC SCALE & METAL CORROSION HARD WATER - SOFTENERS HEAT TAPES, Heat, Insulation prevent Freeze-Up HOT WATER HEATERS KITCHEN & BATH DESIGN GUIDE LEAD POISONING HAZARDS GUIDE MANUALS & PARTS GUIDES - HVAC METHANE GAS SOURCES MIXING / ANTI-SCALD VALVES MUNICIPAL WATER PRESSURE IMPROVEMENTS MOLD INFORMATION CENTER NOISE CONTROL for PLUMBING NOISE, WATER HEATER NOISES, WATER PUMP ODORS & SMELLS DIAGNOSIS & CURE OIL FIRED WATER HEATERS OIL & GAS PIPING OIL TANKS OUTHOUSES & LATRINES PIPING IN buildings, Clogs Leaks Types PLUMBING FIXTURES, KITCHEN, BATH Plumbing Materials & Fixtures, Age, Types PUMPS & WELLS RANGE BOILERS RELIEF VALVES - TP Valves on Boilers RELIEF VALVES - Water Heaters RELIEF VALVES - Water Tanks SEPTIC SYSTEM INSPECT DIAGNOSE REPAIR SEWER GAS ODORS SHUTOFF VALVE LOCATION, USE SOLAR ENERGY SYSTEMS SULPHUR & SEWER GAS SMELL SOURCES SUMP PUMPS GUIDE SUPPLY PIPING SWEATING (CONDENSATION) on PIPES, TANKS TANK TYPES: WATER, OIL, EXPANSION, ALL 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 Temperature Pressure Relief Valves - Water Heaters TIMERS for ELECTRIC WATER HEATERS TOILET REPAIR GUIDE TRAPS on PLUMBING FIXTURES VALVES, PLUMBING WATER FILTERS WATER HAMMER NOISE DIAGNOSE & CURE WATER HEATERS AGE of WATER HEATERS 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 BLEVE EXPLOSIONS DEBRIS in WATER SUPPLY, Water Heater DRAIN a WATER HEATER TANK ELECTRIC WATER HEATERS WATER HEATER SAFETY WATER HEATERS for HOME HEATING USE? GAS FIRED WATER HEATERS SPILL SWITCHES - Flue Gas Detection HOT WATER IMPROVEMENTS HOT WATER DELIVERY SPEED UP HOT WATER EFFICIENCY IMPROVEMENT HOT WATER PRESSURE EXPANSION RATE HOT WATER PRESSURE LOSS HOT WATER QUANTITY IMPROVEMENT INDIRECT FIRED WATER HEATERS KITCHEN & BATH DESIGN GUIDE MIXING / ANTI-SCALD VALVES NO HEAT - NO HOT WATER: HEATER DIAGNOSIS NOISES COMING FROM WATER HEATER ODORS GASES SMELLS, DIAGNOSIS & CURE ODORS IN WATER OIL FIRED WATER HEATERS MIXING / ANTI-SCALD VALVES NO HEAT - NO HOT WATER: HEATER DIAGNOSIS NOISE / SOUND DIAGNOSIS & CURE NOISE CONTROL for HEATING SYSTEMS NOISE CONTROL for PLUMBING NOISE, PLUMBING DRAIN DIAGNOSIS NOISE, PLUMBING DRAIN REPAIR NOISE, PLUMBING CHECKLIST NOISE, WATER HEATER NOISES, WATER PUMP ODORS GASES SMELLS, DIAGNOSIS & CURE ODORS IN WATER OIL FIRED WATER HEATERS PLASTIC HEATER VENT RANGE BOILERS RELIEF VALVES - TP Valves on Boilers RELIEF VALVES - Water Heaters RELIEF VALVES - Water Tanks SAFETY, HEATING INSPECTION SCALE REMOVAL, WATER HEATERS SEWER BACKUP PREVENTION SEWER GAS ODORS SEWER LINE REPLACEMENT 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 TIMERS for ELECTRIC WATER HEATERS TRAPS on PLUMBING FIXTURES VALVES, PLUMBING VENT PIPING WATER CONTAMINANT LEVELS WATER FILTERS 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 EFFICIENCY WATER HEATER FLUSH PROCEDURE WATER HEATER NOISES WATER HEATER PROBLEM DIAGNOSIS 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 EFFICIENCY 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 LOSS DIAGNOSIS & REPAIR WATER PRESSURE PROBLEM DIAGNOSIS TABLE WATER PRESSURE REDUCER / REGULATOR WATER PRESSURE REPAIR GUIDE - WELLS WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS WATER PUMPS & WELLS WATER PUMP CONTROLS & SWITCHES WATER PUMP PROBLEM DIAGNOSTIC TABLE WATER PUMP REPAIR GUIDE WATER PUMP TYPES & LIFE EXPECTANCY WATER PURIFIERS WATER QUALITY TESTS, CONTAMINANTS, TREATMENT WATER QUANTITY IMPROVEMENT WATER SHUTOFF VALVE LOCATION, USE WATER SHUTOFF VALVE, WELL PUMP WATER SOFTENERS & CONDITIONERS DETECT HARD WATER DIAGNOSE WATER SOFTENER PROBLEMS DIAGNOSE WATER BACKUP / FLOODING MEASURE WATER HARDNESS HOW SOFTENERS WORK HEALTH RISKS & WATER SOFTENERS INSTALLATION of WATER CONDITIONERS SALT OR WATER INTO SEPTIC REDUCE IMPACT of SOFTENER on SEPTIC SOFTENER ADJUSTMENT & CONTROLS OTHER SOFTENER METHODS Winterize Water Softener & Treatment Equip Restoring Water Softener & Treatment Equip WATER SOURCE ALTERNATIVES WATER SUPPLY & DRAIN PIPING Water Tank & Pump Costs WATER TANK AIR, HOW TO ADD WATER TANK: USES, TROUBLESHOOTING WATER TANK TYPES: WATER, OIL, EXPANSION, ALL WATER TANK AIR, HOW TO ADD WATER TANK REPAIRS WATER TANK SAFETY WATER TESTS, CONTAMINANTS, TREATMENT WATER TREATMENT EQUIPMENT CHOICES WATER ODORS, CAUSE CURE WATER PURIFIERS WELLS CISTERNS & SPRINGS WINTERIZE A BUILDING More Information |
Here we explain just how to improve the hot water pressure, quantity, flow, and water temperature obtained from a tankless coil used for making domestic hot water. We review aquastat control settings as well as using a flow limiter or an anti-scald mixing valve to improve hot water supply. InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.© 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 Increase Hot Water Quantity & Flow When a Tankless Coil is Installed - how to avoid running out of hot waterIf your hot water pressure is declining because of a clogging tankless coil, be sure to see Clogged Pipes / Tankless Coil De-Scale for diagnosis and repair advice. Thanks to Carson Dunlop Associates, a Toronto Home Inspection Firm and Home Inspection Educator, for permission to use sketches shown in this article. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.
Setting the Aquastat Controls to Higher Temperature for More Hot Water (watch out for scalding)Adjust the aquastat controls. As we explain in detail at See AQUASTAT CONTROL Functions, you can set the Aquastat HI and LO for the boiler to higher temperatures to increase the heat stored in the boiler and thus the hot water quantity produced by the tankless coil. (But still you must keep the HI and LO at least 20F apart). Now if you also set a higher DIFF (move it to 25) you will run the boiler at higher temperatures and will in general store more heat in the boiler. This will cause the tankless coil to provide a more hot water before the boiler itself runs out of heat. The Basics of Getting More Hot Water out of a Tankless CoilEspecially if yours is a modern steel boiler of small (efficient) size, the thermal mass of the boiler itself plus the water inside the boiler, is very small compared with an old-fashioned, physically bigger, maybe cast-iron boiler. So the amount of heat stored in the modern boiler is much less than in the older models. No oil burner on a home heating boiler can put heat into the boiler fast enough to keep heating cold outdoor water coming into the tankless coil and headed up to the hot water side of your shower. [Put another way, a tankless coil on a heating boiler is not capable of giving endless hot water - as you've discovered - while a "tankless water heater" (Tankless Water Heaters) can do that, though depending on size, only at a modest rate.] So once we use up the heat in the boiler, we are out of hot water. The effect of making the boiler come on as soon as possible while the heat is being sucked out of the boiler and into the tankless coil and thence into the cold water running into the hot water side of shower - the effect of all that, is that we slightly extend the hot water time in your shower. That's all. So our object in giving advice about setting the LO and DIFF is
Setting HI 200, LO 180, and DIFF 25 is about as hot as you can get. Watch out: check the relief valve for drips, and also use an anti-scald valve to avoid burns Use a flow limiter to increase the length of time that you can run the hot water and to increase hot water temperatureTankless coils do not provide infinite hot water. Cool water entering the coil draws heat out of the boiler water and into the house water. The oil or gas burner that reheats the heating boiler cannot pump heat into the boiler as fast as the tankless coil is removing heat. That's because water is entering the coil at 40 to 55 deg F in most cases, and it's trying to leave at the boiler temperature that may be close to 200 degF. So if you run water too fast through the tankless coil it'll draw heat out of the boiler quickly and you'll have great hot water pressure, but not for very long. Then you'll just have tepid or cold water pressure. Some tankless coils have a flow limiting valve mounted right at the coil to prevent water from flowing through the coil too fast. Using a flow limiting valve on a tankless coil lets you run the hot water longer before you run out by forcing you to run it more slowly. Use of a flow limiting valve, because it slows the passage of cold water through the water heater, will also permit the water to arrive at the plumbing fixture at a higher temperature - the hot water will be hotter. Intelligent use of shower controls to restrict hot water flow can save hot water costs and provide longer shower bathing timeEven when a flow limiter is not installed in hot water piping, a bather can save on hot water heating costs by smart use of shower controls. Some bathers turn the hot water all the way to it's fastest flow position, followed by turning on lots of cold water in order to avoid being scalded. Instead of this fastest-flow best water pressure approach, turn the hot water to a less powerful stream, which will require also turning on less cold water to obtain a comfortable shower temperature. This method of bathing does not really provide a greater quantity of hot water in a building, but by drawing hot water out of the water heater more slowly, one can either have longer time in the shower, or subsequent bathers can have adequate hot water at less total water heating cost. Use an anti-scald valve to increase hot water quantity and protect from hot water burns
Therefore we can expect to draw a larger quantity of (tempered) hot water from the tankless coil on such a system than otherwise. We will have more total domestic hot water for washing and bathing, and we have safer hot water (non-scalding) than if we omitted this pair of controls. See MIXING / ANTI-SCALD VALVES for a detailed discussion of how to install, set, and use mixing valves, anti-scald valves, or tempering valves on water heating systems to avoid scalding burns and to improve hot water heater performance. Check the settings of the anti-scald valve or mixing valve - setting the anti-scald valve to a lower output temperature means that it mixes more cold in with outgoing hot, drawing heat out of the boiler and through the tankless coil more slowly than otherwise. You get "longer hot water on time" because you draw heat out of the boiler more slowly. See ANTI SCALD VALVES. Make Sure That the Tankless Coil is Not Mineral-CloggedFor details on how to diagnose a clogged tankless coil and how to repair it, see Clogged Pipes / Tankless Coil De-Scale. See TANKLESS COILS for an explanation of how these water heaters work and why they clog up and how to stop clogging up the coil. See Water pipe clog repair guide for a discussion of loss of water pressure due to clogged piping or clogged tankless coils. At Larger Diameter Water Supply Piping we discuss the benefits of using larger diameter water supply piping both to improve water pressure and flow and also to delay the clogging of pipes due to minerals or rust. See WATER SOFTENERS & CONDITIONERS for a discussion of how to use a water softener to prevent hot water pipe clogging and tankless coil clogging (and reduced hot water pressure and flow). A water softener can prevent mineral-clogging of pipes or the tankless coil but regrettably, installing a water softener after your pipes or tankless coil are already clogged will not fix that problem. How do we Improve the Overall Hot Water Volume & Quantity?As we discussed beginning in the previous section of this article, there are several different hot water problems:
Articles Describing Steps to Increase Hot Water QuantityThe articles listed below offer more details about steps one can take to increase hot water quantity, pressure, and flow in a building. Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.
The topics discussed in this article address improving hot water flow and improving hot water total quantity. A Comparison of Alternative Hot Water Heaters & SourcesThe following articles discuss alternative ways to produce domestic hot water for washing and bathing.
The characteristics of various water heaters such as life expectancy, cost, safety, and capacity are discussed at WATER HEATER PROBLEM DIAGNOSIS Ways to improve total hot water quantity, pressure, temperature and flow are discussed beginning at HOT WATER IMPROVEMENTS and continuing at HOT WATER QUANTITY IMPROVEMENT. Questions & Answers regarding this article. Ask a Question or Search InspectAPediaHTML Comment Box is loading comments...
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