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AGE of WATER HEATERS
ALTERNATIVE HOT WATER SOURCES
ANODES & DIP TUBES on WATER HEATERS
ANTI SCALD VALVES
APPLIANCE DIAGNOSIS & REPAIR
APPLIANCE EFFICIENCY RATINGS
AQUASTAT CONTROL Functions
BACKDRAFTING HEATING EQUIPMENT
BACKFLOW PREVENTER, HEATER WATER FEEDER
CARBON MONOXIDE - CO
CHECK VALVES, WATER SUPPLY
CLOGGED SUPPLY PIPING
CROSS CONNECTIONS, PLUMBING
DEBRIS in WATER SUPPLY, Water Heater
DRAIN a WATER HEATER TANK
ELECTRIC WATER HEATERS
FLOODED WATER HEATER REPAIR
FREEZE-PROOF A BUILDING
GALVANIC SCALE & METAL CORROSION
GAS BURNER Flame & Noise Defects
GAS FIRED WATER HEATERS
GAS PIPING, VALVES, CONTROLS
HEATING COST SAVINGS METHODS
HOT WATER EXPANSION TANKS
HOT WATER SUPPLY
HOT WATER IMPROVEMENTS
HOT WATER DELIVERY SPEED UP
HOT WATER EFFICIENCY IMPROVEMENT
HOT WATER PRESSURE EXPANSION RATE
HOT WATER PRESSURE IMPROVEMENT
HOT WATER PRESSURE LOSS
HOT WATER PROBLEM DIAGNOSIS
HOT WATER QUANTITY IMPROVEMENT
HYDROGEN SULFIDE GAS
INDIRECT FIRED WATER HEATERS
MANUALS & PARTS GUIDES - HVAC
MIXING / ANTI-SCALD VALVES
NO HEAT - NO HOT WATER: HEATER DIAGNOSIS
NOISE, WATER HEATER
ODORS IN WATER
PIPING IN buildings, Clogs Leaks Types
RELIEF VALVE LEAKS
RELIEF VALVES - Water Heaters
SCALE REMOVAL, WATER HEATERS
SEWER GAS ODORS
SOLAR HOT WATER HEATERS
TANKLESS WATER HEATERS
THERMAL EXPANSION of HOT WATER
THERMOSTATS, WATER HEATER
TIMERS for ELECTRIC 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 COMPARISONS, PROPERTIES
WATER HEATER SCALE
WATER HEATER SAFETY
WATER HEATERS for HOME HEATING USE?
WATER ODORS, CAUSE CURE
WATER PIPES, Clogs Leaks Types
WATER PRESSURE TOO HIGH: DANGERS
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER QUANTITY IMPROVEMENT
WATER SOFTENERS & CONDITIONERS
WINTERIZE A BUILDING
Tankless heater coil installation on a boiler: this article describes the steps in installing or replacing a tankless coil on a hot water (hydronic) or steam boiler. Tankless coils are used to provide domestic hot water by heating building water as it passes through a heat-exchanging coil immersed in the heating boiler's hot water contents.
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At page top we include a sketch showing the typical installation of a tankless coil on a residential heating boiler. Notice in the page top sketch that a mixing valve or anti-scald valve has been installed between the cold inlet to the tankless coil and the hot outlet pipe from that device.
At left we've adapted a U.S. Energy.gov sketch from a confusing article that mixes up TANKLESS COILS (boiler-mounted devices that we discuss in this article), INDIRECT FIRED WATER HEATERS (a tank of hot water heated by a heat exchanger inside the tank that itself is heated by water from the heating boiler), and TANKLESS WATER HEATERS (stand-alone, instant, tankless water heaters). - U.S.DOE (2014)
As you can see, a tankless coil used for making hot water is a heat exchanger that is inserted into the heating boiler's very hot water. As cold water flows through the inside of the tankless coil it is heated up, leaving the coil hot.
On some heating boiler designs the tankless mounting plate is round (photo below). When I find a pile of tankless coils like this I know the building occupants have not been having a good time in the shower. On other tankless heater coil designs the coil mounting plate may be round as we illustrate in M.C.'s photo later in this article. And tankless coils may mount on any of the boiler sides or even on its top, depending on the boiler's design.
Step by Step Tankless Coil Installation Procedure
Watch out: when installing a tankless coil to follow the manufacturer's instructions about handling and sealing the boiler-to-coil gasket (some may specify no sealant is used), and about uniform torquing of the coil faceplate mounting bolts.
At left we illustrate the typical piping arrangement into and out of a tankless coil water heating system. Cold water is piped to an inlet marked "COLD" and building hot water supply piping is connected to the tankless coil outlet marked "HOT".
[Click to enlarge any image]
This tankless coil piping example from Crown Boilers indicates the use of a mixing valve or anti-scald valve right at the heating boiler. The company includes an interesting warning reading as follows [Quoting - Crown BDS Installation Manual]
WARNING: Thermostatic mixing valves are intended to increase the supply of hot water available from the coil. They are not intended to prevent a scald hazard.
Really? I speculate that the company's lawyers got a hold of this one - nobody wants to be named in a scald lawsuit. Some manufacturers may hold the view that anti-scald devices should be installed at each fixture, at the point of use.
Our photo shows a typical mixing valve produced by Watts Regulator Co. The mixing valve manufacturer's installation instructions for these devices include similar warnings.
Also be sure to follow the mixing valve manufacturer's installation instructions. For example Watts recommends:
To prolong the life of the Model LF1170-M2 or LFL1170-M2 valve [not shown here], it is recommended that it be trapped as shown ...: i.e. the hot water inlet to the LF1170-M2 valve should be 8" – 12" (200 – 305mm) below the hot water supply feed. - "Instructions Series LF1170 and LFL1170 Hot Water Temperature Control Valves", Watts Regulator Co. (2013)
do I leave-on or remove tie wires found on the tankless coil before I install it on my heating boiler?
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