An Inspection Guideline
This inspection guide will cover and explain the three most often used methods of installation for water heaters, such as,
- Natural draft, tank, and gas water heaters installed using galvanized steel vent piping.
- Electric water heaters.
- Gas, tank and power vent equipped water heaters using PVC vent pipe.
It is recommended you obtain a water heater inspection manual from your local building permit department to have the most recent rules and regulations covering installations and inspections.
Cold Water Supply and the Shutoff Valve
Inspect the union connectors. These are usually required to be within 12” of the water heater’s inlet and outlet side. The dielectrics and unions you see here are safe for all types of water pipe materials as they provide a separation of metals that may corrode. The water shutoff valve must also be placed near the water heater and only a full bore valve type is permitted here.
All unions must be inspected for leaks. It is also important to know that sometimes certain water heaters types will require heat traps or heat loops if there are flexible lines present. Most of the time, heat traps are built into the unit from the manufacturer, but inspect for this. This type of trap prevents cold water mixing with hot water.
Supply side water lines and the materials used for water distribution can vary from city to city across America. They can be plastic, copper, galvanized and in some older buildings the use of lead pipes is still allowed. If the Universal Plumbing Code(UPC) has been chosen for your city, then thermal resistance insulators must be a minimum of R4. The insulation must start within 5′ from the water heater’s inlet and outlet.
Water Heater Insulation
Recent advances in water heater technologies include insulation measuring at a minimum of R12 or higher. This means the outside of the tank may not require insulation for optimum production. However, an extra layer of insulation is recommended and in some climates may be necessary.
Water Heater Thermostat Settings
Thermostat settings can become safety issues and must be in line with code requirements. The most often recommended setting is under 125ºF. This temperature is still a potentially hazardous one. Touching the side of the tank at this temperature continuously can result in 2nd or 3rd degree burns.
The Safety Drip Pan
A water tight drip pan is required under the water heater and care must be taken to ensure it is installed correctly. It’s minimum depth must be 1 ½” and must be made of galvanized steel or plastic. It must have a minimum drain of 3/4” with a pipe pitched for correct drainage into an approved location. This location can be outside within 6”-24” from the ground. It can also be connected to a sewer line or vent pipe. It can also be directed to a floor drain or an indirect water receptor.
Combustion Air Requirements
Water heater single wall vent pipe connections must be connected with sheet metal screws. The draft hood must be connected with these also. Duct tape is not allowed as it is not effective in this situation and prevents the observation of possible corrosion points in the piping.
A single wall water heater vent pipe must have a minimum of 6” clearance from combustion areas. A double wall installation with a B-vent type connector must have a minimum of 1” clearance from areas of combustion.
Power vent type water heaters using PVC piping connections must be inspected for tightness and corect sealing. Check glued seals and insure cement is current. An air tight joint is required.
Gas supply lines should have sediment traps to trap moisture and prevent gas valve and thermostat contamination. It should be placed as close to the water heater’s gas valve as possible.
The gas connector type should be verified with local building code or the supplying company. Hard connectors are required except in geographical areas where there is seismic activity. Check for a valve/back flow preventor on the cold side. If this is being used, then an expansion tank will be necessary.
Electric Water Heater
These types require lockable or in-sight disconnects. A circuit breaker must be dedicated at 220V. There must be a grounding terminal screw and a grounding wire. This wiring must be contained within one compartment and the power supply must not touch the water piping.
Natural Draft, Tank Type
These types of water heaters require an adequate amount of air to produce complete combustion. Unions or a flange connections are needed between the gas shutoff and the water heater.
The benefits of this type centralize around the fact that they are natural. They don’t use electricity so if you don’t have power for a while, you can still have hot water. They are pretty quiet also. They are inexpensive coming in at about half the price of powervent water heaters. Because they don’t have moving parts, they tend to be more reliable than other types.
Single Wall Vent Pipe Installation Locations
- Vent pipe may not be installed in the wall or ceiling cavities.
- Vent pipes may not go through walls, floors, or ceilings.
- Vent pipes may not be installed in an unheated location.
- Vent pipes may only be installed in the same room as the water heater.
Temperature Pressure Relief Valve(TPR)
Tank type water heaters require a correctly installed TPR valve. This valve must also have a properly sized safety discharge pipe made from approved materials.
The TPR valve is a safety device that will release pressure from a water heater if the temperature rises sharply. Explosions may happen if the thermostat continues to call for heat and extreme temperatures are reached.
Inspecting the TPR involves touching the drain line and assessing it for temperature. You can raise the test lever on the valve and listen for water discharging. If water does not discharge, then you may have a faulty TPR. If water is leaking at the top of the tank, it is most often indicating the need for a TPR replacement. Check for leaks in all areas.
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