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- author "me"
- tags "Hvac 101"
- description ""
- fileName "Water heater
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- 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.
- Constucted in steel
- - inside of the tank is constructed of a glass lining bonded to the steel.
- - prevent from rusting water to metal contact.
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.
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.
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.
- - 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.
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,
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.
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.
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
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.
Water heater expansion tank
It expands, reacting to physical law, water expands in volume as its temperature rises.
Cross connection means " no return "
Water os not compressible
Three tools need for pre-installation of a water heater expansion tank
- - water pressure gauge
- - tire pressure gauge
- - bicycle pump
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
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
flammable vapor ignition resistant
- Corderite combustion containment;
- Design features a sealed (from non designated air intake openings) combustion chamber and a flame arrestor component.
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
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
Three things need for therm-x-trol installation
- Bicycle pump
- Tire gauge
- Wate pressure gauge