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- author "me"
- tags "Hvac 101"
- description ""
- fileName "Water heater
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- freezingBlueDBID -1.0
- Electric Water heater elements
- - upper heating element takes priority to heat
- - lower element heats the incoming cold water
- - residential electric water heater usually has two 4500 watt screw-in type heating element and wired in not to get energized both elements at the same time so the wiring is sized as a single 4500 watt load.
- - temperature rise is the increase in water temperature from its coldest inlet water temperature to the desired hot (outlet setting) typically 40 or 80 degree.
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Tank construction
- Constucted in steel
- - inside of the tank is constructed of a glass lining bonded to the steel.
- - prevent from rusting water to metal contact.
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Water heater construction
- An anode rod is a self sacrificing rod installed within the tank to help prevent corrosion.
- The hex plug end of the anode is visible on the top of the water heater.
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Water heater components
- - one or more thermostat(s) to operate the heater.
- - one high limit to prevent over heating of the water.
- - all water heater mus have a temperature and pressure (T&P) relief valve.
- - opens at a temperature of 210 degree F.
- - opens at a pressure of 150 PSI.
- - all water heater has a dip tube inside the tank that carries the cold inlet water to the bottm of the tank.
Note: if limit switch got stuct together and waters got hot, and then cool it down and never warm up again. The solution of this problem is replaced both limit and thermostat.
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Gas water heater control
This control has a main gas regulator, on-off pilot knob, controls water temperature, has a temperature adjustment knob and has a high water temperature limit safety.
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Temperature
- - two metal probes on the back of the control are immersed inside the tank.
- - the shorter probe is the high temperature limit.
- - the longer probe contains a metal rod hat expands and contracts as the water temperature is heated or cooled which opens or closed the flow of the gas.
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Gas water heater burner
- The burner assembly consists of:
- the main buner,
- main burner orifice,
- main burner gas supply tube,
- Pilot burner,
- Pilot burner orifice,
- Pilot burner gas supply tube,
- Thermocouple.
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eletric Water heater inspections
- - check thermostat setting: recommended 125° F. or customers preference.
- - check operation and amperage of each element (18.75 amp for 4500 watt at 240 vac)
- - look for the sign of leakage around elements and fittings on top of water heater.
- - look for signs of burned or discolored electrical connectins.
- - drain sediments from bottom of tank.
- - wipe off any dust or lint.
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Procedure of replacement of electric water heater element on water in the tank
- 1. Turn off power
- 2. Turn off water - cold water inlet valve
- 3. Open the faucet and let run the hot water until no water is coming out
- 4. Close the faucet and let no one turn the hot water faucet until finishing the replacement
- 5. Loosen old element with wrench
- 6. Have new element ready
- 7. Unscrew old element and remove and quickly install new element and tighten.
- 8. Tighten with wrench and check for leaks.
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Gas water heater inspection
- - check temperature setting on water heater control (gas valve) "hot" is about 120°F and "very hot" is about 160° F.
- - inspect combustion chamber and burner assembly for rust, soot or lint. Vacuum as necessary
- - check plot assembly and thermocouple
- - make sure all gas connection are tight and no odor of natural gas.
- - clean lint screen on newer water heaters with flammable vapor ignition restraint design.
- - check for signs of leak or corrosion on water fittings.
- - inspect condition of vent and vent connector fr rust, soot, or corrosion. ( if vent connector rusts and falls off, carbon monoxide poisoning will occur which is odorless, colorless, tasteless)
- - inspect burner flame
- - drain sediment from bottom of tank
- - wipe off or vacuum any dust or lint
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Why water heater is leaked
- - excessive water pressure due to thermal expansion.
- - the T&P relief valve leaking on ocassion is a symptom of thermal expansion.
- - adding a thermal expansion tank corrects thos problem.
- - excessive mineral build-up
- - this coat or insulates the metal surfaces causing the surfaces to become hotter.
- - you may noice a rumbling, cracking or poping, boiling noise.
- - flush the sediments sand from the tank.
- - water temperature set too high
- - hotter water is more corrosive and cause excessive expansion and contraction of the metal.
- - setting the water temperature at 125°F.
- - contaminated air espacially gas water heater
- - bleaches, detergents, and other household products contain chemicals that when they contact the flame various acids form that attack the metal.
- - make sure water heater is supplied with clean air.
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Water heater expansion tank
It expands, reacting to physical law, water expands in volume as its temperature rises.
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Cross connection means " no return "
Water os not compressible
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Three tools need for pre-installation of a water heater expansion tank
- - water pressure gauge
- - tire pressure gauge
- - bicycle pump
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Flammable vapor ignition resistant design (FVIR)
- In additional to the standard water heater design
- - a LDO ( lint, dust,oil) screen over the combustion air leaks
- - a flame arrestor
- - combustion chamber temperature sensor
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TCO ( thermal cut off) functions
- - due to a clogged LDO screen or inadequate air for combustion
- - in the event of flammable vapor ignition inside the combustion chamber, it senses the corresponding increase in temperature and the it shut off the gas flow.
- - temp. Range between 160°C to 200°C depends on model
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FVIR
flammable vapor ignition resistant
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C3 technology
- Corderite combustion containment;
- Design features a sealed (from non designated air intake openings) combustion chamber and a flame arrestor component.
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C3 technology design also include
- A LDO (lint dust and oil) screen over the combustion air intake
- a flame arrestor
- A combustion chamber thermal cut off (TCO) limit
Also, features with Piezo Igniter
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Five point inner door seal inspection for C3 tech.
- - inner door gasket condition and fit
- - main burner tube seal condition and fit
- - pilot assembly seal condition and fit
- - sight glass, condition; present, not broken or cracked
- - straight routing of the thermocouple and pilot burner tube through the pilot assembly seal
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Three things need for therm-x-trol installation
- Bicycle pump
- Tire gauge
- Wate pressure gauge
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