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AGE of WATER HEATERS
AIRBOUND HEAT SYSTEM REPAIR by WATER FEED VALVE
ALTERNATIVE HOT WATER SOURCES
ANODES & DIP TUBES on WATER HEATERS
ANTIFREEZE for BOILERS
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
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
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
GAS PIPING, VALVES, CONTROLS
HEAT TAPES, Heat, Insulation prevent Freeze-Up
HEATING COST FUEL & BTU Cost Table
HEATING COST SAVINGS METHODS
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
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
NOISE, WATER HEATER
ODORS GASES SMELLS, DIAGNOSIS & CURE
ODORS IN WATER
PIPING IN buildings, Clogs Leaks Types
PLASTIC HEATER VENT
PLUMBING FIXTURES, KITCHEN, BATH
PLUMBING VENT DEFECTS & NOISES
PUMPS, HEAT PUMPS
PUMPS, OIL BURNER
PUMPS, PONY PUMPS
PUMPS, SEPTIC PUMPS
PUMPS, SEWAGE EJECTOR / GRINDER PUMPS
PUMPS, SUMP PUMPS
PUMPS, WATER PUMPS
PUMPS, WATER REPAIR
RELIEF VALVE LEAKS
RELIEF VALVES - TP Valves on Boilers
RELIEF VALVES - STEAM TP VALVES
RELIEF VALVES - Water Heaters
RELIEF VALVES - Water Tanks
SAFETY, HEATING INSPECTION
SCALE REMOVAL, WATER HEATERS
SEWER GAS ODORS
SOLAR HOT WATER HEATERS
SOOT on OIL FIRED HEATING EQUIPMENT
SPILL SWITCHES - Flue Gas Detection
TANKLESS WATER HEATERS
THERMOSTATS, HEATING / COOLING
THERMOSTATS, WATER HEATER
TIMERS for ELECTRIC WATER HEATERS
WATER CONTAMINANT LEVELS
WATER HAMMER NOISE DIAGNOSE & CURE
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
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 GAUGE ACCURACY
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PRESSURE REDUCER / REGULATOR
WATER PRESSURE PUMP REPAIR GUIDE
WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
WATER PUMP REPAIR GUIDE
WATER QUALITY TESTS, CONTAMINANTS, TREATMENT
WATER QUANTITY IMPROVEMENT
WATER SOFTENERS & CONDITIONERS
WINTERIZE A BUILDING
Here we explain the use of Tankless Coils on heating boilers: a guide to tankless coils for domestic hot water supply: capacity, safety, clogging, adjustment, cleaning, & Repair Guide
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How much hot water can a tankless coil provide?
The temperature and effective quantity of domestic hot water received at a fixture in the building for washing and bathing is set, affected, or controlled by these things:
Considering these factors, you can understand that converting a large old cast iron home heating boiler with a tankless coil to a new small high-efficiency steel heating boiler that also includes a tankless coil may result in a new heating system which is more efficient and economical, but it may provide less total domestic hot water than the old system.
Use of a Single Function Boiler Temperature Limit switch and Anti Scald Valves with Tankless Coils
Diagnosis & Repair Articles for Tankless Coils used to Produce Residential Hot Water
How to get more hot water pressure and more hot water quantity from a tankless coil
See Tankless Coil Hot Water Increase and HOT WATER IMPROVEMENT for a detailed guide to improving hot water quantity and flow when a tankless coil is installed as well as using other methods of hot water heating
How to avoid being scalded by hot water from a tankless coil
See MIXING / ANTI-SCALD VALVES for details about mixing valves on boilers and tankless coil systems and for an explanation of how an anti-scald or tempering valve can increase the volume of hot water available from a tankless coil hot water system.
How to deal with clogged hot water piping that reduces hot water pressure and flow
What to do about leaks at the tankless coil
Please see Tankless Coil Leaks for a detailed discussion of how to recognize, evaluate, and repair boiler leaks on or around the tankless coil.
Also see BOILER LEAKS CORROSION STAINS for a discussion of leaks on heating boilers.
Frequently Asked Questions (FAQs) about making domestic hot water using a tankless coil or side arm coil: installation, inspection, troubleshooting, repair guide
Question: how do I get the furnace to stop heating my tankless coil after I switch to a separate hot water heater?
Hey I'm installing an electric water heater in my new home, I have a Weil mclein furnace and it heated my water to the showers and faucets and it's costing me a fortune in oil so I'm switching how do I get it so the furnace doesn't heat the water anymore just heat the house? Would I have to remove the coil and
Question: is it normal for the boiler to turn on when the thermostat is not calling for heat and no hot water is being used?
I'm renting my first house have baseboard heat. a coil in my furnace. Is it usual for the burner to come on when your baseboard thermostats are off and there is no hot water being used? It seems to fire up hours after someone has taken ashower or washed dishes/hands. all summer this has happend - Smokey G 10/3/12
Question: do we need a temperature & pressure relief valve on the output side of a tankless coil?
Should there be a TPR valve on the DHW "hot",i.e., "out" side of a combination boiler coil? - Vince 11/2012
Sorry, I see in this article that "Some building jurisdictions require a separate temperature/pressure relief valve on hot water piping at the boiler." I'm just trying to figure out in what scenario a TPR would trigger with such a system. Also, since TPR valve usually have the "melting rod"; it's difficult to install them directly in the pipping. It is possible with a 4" length of 3/4" pipe but that seems to contradict most installation instructions for those valves.
Thanks for the comment, Vince.
Question: I have to turn our room heating thermostat and wait before we can get hot water out of the tankless coil
My wife and I just bought a house with an oil boiler for heat/hot water. For showers I have to crank the heat to 80, wait 8-10 minutes for the boiler to kick on, turn heat back down, wait a few more minutes, then take a quick 2 minute shower that starts at 150 degrees and ends at about 70. The heat seems fine but just takes a few minutes from thermostat change to boiler kicking on. The water, however, goes from lukewarm to ice cold in 20 seconds if I don't go through the routine. What should I check for to remedy this?
John, I don't have a clear picture of all the equipment you have installed, but it sounds as if your boiler controls may not be set properly; The LO and DIFF are what keep the boiler hot to provide hot water beween calls for heat.
Thank you. I checked and it looks like there is only one control which is set at 155 degrees? I had a plumbing emergency and while he was there the plumber checked and said it was fine at that temp. We still have no hot water unless the boiler is running, which must be manipulated by cranking the heat up.
John, it would be unusual to use a tankless coil on a heating boiler with a boiler primary control aquastat that was designed ONLY for heating - that is, that did not include a LO and DIFF control to provide hot water when there was no call for room heating. I suspect the unit doesn't have the proper type of aquastat.
Questions & answers or comments about tankess coils for making domestic hot water: installation, diagnosis, repair, & adjustment of temperatures & hot water capacity, clogging, & coil cleaning procedures
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