To dismantle and reassemble domestic Gas Geyser i.e. Gas Water Heater

Size: px

Start display at page:

Download "To dismantle and reassemble domestic Gas Geyser i.e. Gas Water Heater"

Beverly McCoy
5 years ago
Views:

1 Experiment No. 1 Aim To dismantle and reassemble domestic Gas Geyser i.e. Gas Water Heater Objective 1) To study construction and working of Gas Geyser 2) To study the problems associated and rectify the same 3) To carry out dismantling and assembling of Gas Geyser Components of the Gas Hot Water Heater The standard "tank type" water heater is found in most homes and with just a little maintenance, provides years of trouble free operation. Unlike tankless water heaters which have no storage tank, the tank type water heater heats cold water and stores the hot water until it is needed. The gas water heater works by a law of physics called convection. As seen in the diagram, cold water is supplied to the tank and injected at the bottom of the tank through a dip tube. The denser cold water stays there and is heated by the gas burner. As the water heats up, it naturally rises and is drawn off by the hot water discharge pipe. In the diagram shown, the hot water pipe is much shorter than the cold water pipe. This ensures that only the hottest water is being used from the tank. The hot water heater has simple parts and some safety features. Major components of the hot water tank. 1) Hot Water Tank The tank jacket is made of steel and encloses a pressure tested water storage tank. Between the storage tank and the tank jacket is insulation to reduce heat loss of the heated water. It is a good idea to supplement the insulation by adding a fiberglass insulation tank jacket to the outside of the hot water heater. These are inexpensive and easy to install. Inside the tank you will see a dip tube. The dip tube is where the cold water supply enters the tank to be heated by the gas burner. Since cold air and cold water is denser than hot air or hot water, the cold water sets at the bottom of the tank until it is warmed

2 by the burner and heated enough to rise (through convection) to the top of the tank where the hot water hangs out. In glass-lined tanks there will also be a metal rod in the tank, usually magnesium or aluminum called a sacrificial anode. The anode rod is bolted and fastened to the top of the tank and extends deep into the tank. It's purpose is to draw corrosion to itself instead of the metal tank. 2) Gas Burner Control Module The natural gas or propane is supplied by a pipe having its own gas shutoff valve. Just like you need to know where the water supply shutoff valve is located, you need to know where the gas line shutoff is located too. The gas line fees into a gas burner control module that serves as a kind of thermostat for the water heater. It also controls the ignition of the pilot light. From the control module we now proceed to the gas burner assembly. This includes the pilot light and gas burner itself. The pilot light and burner adjustment are key to proper and energy efficient operation of the water heater. The gas flame should about 1/2 inch in height and should have blue tips. 3) Gas Combustion Exhaust Flue The exhaust flue serves two purposes. It exhausts combustion gasses from the burner and it serves as a type of heat exchanger helping to heat the water in the storage tank. The flue must be properly exhausted to the outside and there are specific code requirements for the type of flue construction and acceptable details. 4) Temperature and Pressure Relief Valve A safety feature of the hot water heater includes the pressure relief valve and discharge pipe. It operates like the radiator cap on your car. The purpose of this valve is to relieve excessive temperature or pressure build up inside the tank if it approaches the limits of the tank's safe design range. This valve is located on top of the tank and often is threaded directly into the tank top itself. To test the valve, lift up on the handle slightly and hot water should discharge out of the overflow pipe. 5) Tank Drain Valve The hot water tank can build up sediments in the bottom of the tank if left unmaintained and by draining the tank using the tank drain valve these sediments cannot build up. And if you don't have sedimentation then that helps to prolong the life of your tank and improve water quality.

3 Trouble Shooting Guide: Water heaters are generally very reliable but occasionally they do have problems. These problems can include: Hot water is not produced: - Faulty gas pilot - Faulty gas thermocouple - Faulty gas pilot control valve - Faulty electric thermostat - Faulty upper electric heating element - Possible Repairs - Check gas pilot flame and pilot operation. - Re-tighten, reposition or replace the gas thermocouple. - Replace the gas pilot control valve. - Confirm power is being provided to the electric water heater thermostat. - If power is being provided to electric thermostat, replace thermostat or heating element. Inadequate Hot Water - Unit is undersized for water heating demands - Broken or damaged dip tube allowing cold and hot water to mix in tank - Faulty plumbing installation has crossed cold and hot water connections - Gas supply or control problems - Faulty electric lower or upper heating element or high or low heating element thermostat. - A constant supply of lukewarm water during a shower is indicative of a defective upper heating element. Short duration hot water supply during a shower is indicative of a defective lower heating element.

4 -Possible Repairs - Make sure water heater is not being overtaxed by hot water supply demands. - Undo cold water inlet and pipe nipple and remove dip tube. Check condition and replace if required. - Check for crossed connection by turning off water supply to water heater. Open hot water tap at a faucet. If there is water flow, then a cross connection exists somewhere. Check for a hot water line connected to a cold water connection on the water heater or appliances such as washer, dishwasher, faucet or shower valves. - Check for proper flame from burner. A natural gas flame should be a bright blue with the tip of the flame having just a tinge of yellow. A propane flame should have a bluish green flame with a tinge of yellow at the tip. - Check for power and electrical continuity at the lower and upper heating elements. Replace water heating element if necessary. Clear tank of any sediment first. - If elements test OK, check for power at upper electrical upper thermostat. If OK check lower thermostat. Replace if necessary. Rust colored water -Corrosion occurring inside glass lined tank -Sacrificial anode rod is failing (anode rods dissolve slowly to prevent rusting in the tank) - Possible Repairs -Replace sacrificial anode rod with magnesium anode rod. Anode rods are available from a plumbing supply house. Rotten Egg Smell Bacteria in the tank sediment fed from hydrogen gas created from decay of sacrificial anode. - Possible Repairs -Flush water heater -Using a hydrogen peroxide solution treat tank and run some of the solution into water lines.

5 -Let peroxide solution set in tank and pipes for 2 hours. Solution is not toxic and requires no rinsing. -If problem persists, replace anode with a zinc-alloy anode. -If problem still remains, replace water heater with a plastic lined tank type. Water Leak Around Base of Heater -Faulty T&P (temperature and pressure) relief valve -T&P valve leak due to excessive pressure, overheating or stuck -Leak from overhead or nearby plumbing connection -Leaking water tank (corrosion likely) - Possible Repairs -Place bucket under overflow pipe. Open and flush Temperature and Pressure valve clear of debris. If leak remains from valve, replace valve. -Reduce thermostat setting to prevent tank overheating and opening Temperature and Pressure relief valve. -Inspect bottom of tank by looking through combustion chamber. If water marks or heavy rusting is noticed or if water is noticed setting in combustion chamber bottom, then the water heater needs to be replaced. Conclusion: From this experiment we have studied the working of Gas Geyser and also the assembling and dismantling procedure of the same.

7 Fig: Gas Control Valve Assembly Fig: Flue Vent

8 Fig: Temperature and Pressure Relief Valve Fig: Tank Drain Valve

COMMERCIAL ELECTRIC WATER HEATER OWNER S MANUAL OPERATION AND MAINTENANCE INSTRUCTIONS

COMMERCIAL ELECTRIC WATER HEATER OWNER S MANUAL OPERATION AND MAINTENANCE INSTRUCTIONS Make sure to follow the instructions mentioned in this manual in order AVERTISSEMENT to reduce the risk of fire, explosion,