Plumbing
2 possible cross-connections at basins and sinks
vegetable sprayer left lying in sink, extendable faucets
what is the minimum width of space needed for a toilet installation?
30 inches
what is the minimum height of a vent pipe above the roofline?
6 inches
what is the recommended horizontal spacing of supports for copper piping?
6 to 10 feet
where does the discharge tube from the temperature/relief valve have to dump water in cold climate? in warm climate?
6 to 12 inches above the floor beside the hot water tank, 6 to 24 inches above grade level outside of the house
what is the approximate temperature rise designed in residential water heaters?
90 degrees
methods of reducing the freezing risk of pipes in cold environments
insulating the pipe, wrapping the pipe in a heating cable
A water heater is termed a single-pass appliance because _______________.
it does not use a recirculating system
Why is PVC or ABS plastic piping usually allowed only in a single-family home?
it is combustible
what is the biggest impact of the single pass feature on a water heater?
it is constantly exposed to fresh water and so is more prone to corrosion than a boiler.
why in a cold climate is the trap portion of the drainage system most vulnerable to freezing?
it is the only portion of the drainage system that always contains water
what is the function of a stop and waste valve?
it shuts off the water supply and allows the system plumbing to be drained
explain briefly the problem with venting kitchen island sinks
kitchen islands are not adjacent to walls; therefore, the vent pipe is some distance from the island, often exceeding the maximum allowable distance between the trap and the vent
what is the implication of improper support on piping?
leakage
common problems with hose bibb
leaks/drips; stiff or inoperative; no backflow prevention; loose; pipe frozen or split; poor slope on frost-free hose bibb; mechanical damage
common faucet problems
leaks/drips; stiff/inoperative; loose; cross connection; noisy; rusted/damaged/loose/missing handles; hot and cold reversed; obstructed aerator; shower diverter inoperative/defective
common bathtub problems
leaks; rust; surface defects; cross-connections, overflow leaking; disconnected/loose; slow drains; unstable
explain briefly the simple test required to check the venting system when you test functional drainage from a fixture
listen for gurgling as the last bit of water leaves the drain, and smell for sewer odors
problems found in vents
missing; ineffective; incomplete; poor vent pipe arrangement; too small or too long; island venting problems; vent termination problems; automatic air vents
Are fan-assisted water heaters condensing?
no
Can polybutylene piping be used on a hot water recirculating loop?
no
is a vacuum necessary to have backflow at a cross connection?
no
what is the purpose of a baffle or turbulator in a gas fired water heater?
to slow down the exhaust products as they move up through the water heater
what is the purpose of a high-level alarm with a sewage ejector?
to warn the occupants that the sewage ejector pump has failed.
A house with several different styles of crimp rings should be a cause for concern. t/f?
true
Every trap should be provided with some method of removal or cleaning. t/f?
true
Pipe size should always increase as you move downstream and more fixtures join in. t/f?
true
Polybutylene supply piping should not be closer than 18 inches to a water heater. t/f?
true
Surface cracking in an acrylic kitchen sink is not usually a concern because there is no leakage. t/f?
true
sewage ejector pumps should not vibrate significantly when running. t/f?
true
vertical pipes at ends of runs are one method of preventing water hammer t/f
true
how high above the floor should a gas/oil water heater be in the garage?
18 inches
when was copper supply piping first used?
1930s
at least how far should an outdoor vent termination be above an operable door?
2 feet
what is the typical vent size on a sewage ejector pump?
2 inches
what is the typical maximum distance between the fixture and the trap?
24 inches
minimum diameter of water service piping in modern construction
3/4 inch
3 things that can go wrong with water supply
1) pressure/flow insufficient 2) leaks 3) dirty water
what is the required slope for nearly horizontal pipes in drain, waste, and vent systems?
1/8 to 1/2 inch fall per foot run
what is the purpose of a trap?
to prevent sewer odors from entering the home through plumbing fixtures
what is the recommended horizontal spacing of supports for galvanized steel piping?
10 to 12 feet
what are 2 typical primary exhaust pipe materials for a fan assisted water heater?
ABS or PVC piping
what is the minimum trap arm length?
At least 2 pipe diameters.
explain the purpose of a backwater valve
To protect the home against sewer backup.
how do the volume of the water and the size of the burner in a water heater relate?
a larger burner means a high recovery rate, which allows a smaller tank to be installed.
describe a cross connection
a piping arrangement in which waste can back up into the supply piping and contaminate it when the pressure drops on the supply side
describe 2 types of hose bibbs
a stop and waste valve prevents water from sitting where the pipe will freeze by isolating the through wall section of the pipe, and draining the trapped water out through the waste valve a frost-proof valve prevents water from sitting where the pipe will freeze by having the valve body remote from the hose bibb, and a slope to drain to the interior
describe the function of a trap
a trap prevents sewer gases from entering the house through the fixture drain outlet
what are the 3 components required on the discharge line from a sewage ejector pump?
a union, a check valve, a gate valve
What is a wet vent?
a wet vent occurs when the drain for one fixture is serving as the vent for another
Polybutylene piping failures seem to be concentrated MOST at: a. the crimp rings b. elbows in the pipe c. horizontal splits in the piping d. at the connection to fixtures e. in vertical pipe runs only
a. the crimp rings
If we only need a pressure relief valve because the water heater has some internal temperature control, where can this pressure relief valve be?
anywhere near the tank, or on piping near the tank in some jurisdictions
at what interval is vertical support required for copper piping?
at least every 10 ft, or every floor level
Where is the burner located on gas- and oil-fired water heaters?
at the bottom of the tank
where should the floor drain be located?
at the low point in the floor
3 types of faucet related noise
bang, chatter, whistle
Why can plastic pipe not typically be used between units in shared dwellings?
because it is combustible
why is a water hammer more common in a house with cartridge faucets than with compression faucets?
cartridge faucets can opened and closed more quickly
what is the implication of poor manifolding?
clogging of pipes
what can cause a toilet to sweat?
cold supply water on a warm, humid day can cause the toilet tank and toilet fill pipe to sweat, particularly if it is not allowed to warm up because of a running toilet
what is the implication of a cross connection?
contamination of a potable water supply
materials commonly used for water service piping
copper, galvanized steel, lead, PVC plastic, CPVC plastic, polybutylene plastic, cast iron, asbestos cement, brass
materials used for piping in drain/vent/waste systems
copper; ABS plastic; PVC plastic; cast iron; lead; galvanized steel; brass; clay
common materials used in venting systems
copper; galvanized steel; cast iron; ABS plastic; PVC plastic
what is the component that introduces cold water near the bottom of a gas-fired water heater tank?
dip tube
which type of water heater has the slowest recovery rate? which has the fastest?
electric water heater, oil water heater
Copper pipe does not rust. t/f?
false
It's impossible for a trap to be too big. t/f?
false
Nearly horizontal vent pipes should slope slightly down away from the trap they are protecting. t/f?
false
Testing for loose wall hung basins is best done by putting all your weight on the basin. t/f?
false
a running trap is a good idea because it provides extra protection. t/f?
false
a waste pipe is intended to carry solids only. t/f?
false
plastic piping needs less support than copper piping because it tends to expand more t/f
false
running toilets are less prone to sweating because the water in the tank is constantly replenished. t/f?
false
the vent diameter must be as large as the trap diameter. t/f?
false
the vent is typically located upstream of the trap. t/f?
false
locations in a house where they may be a cross connection
fixtures where the faucet spout is below the overflow or flood rim; fixtures where handheld showers, extendable faucets or vegetables sprayers can be lefts in tubs, basins, or sinks; garden hoses attached to a hose bibb; toilet tanks where fill water enters at bottom; dishwasher where a solenoid valve separates the clean water from the gray water; clothes washer discharging into a laundry tub; water softener; humidifier connected to the supply piping; lawn or fire sprinkler system; bidets where water enters at the bottom of the bowl; hot water boiler; swimming pool fill outlet located below the flood level of the pool; a trap primer without an air gap
materials used as water supply piping
galvanized steel, copper, polybutylene (PB), polyethylene (PE), CPVC, brass, stainless steel
how do you determine if the toilet connection to the drain piping is loose?
grasp the bowl between your legs and try to move the bowl from side to side and front to back
When would a fan-assisted gas water heater typically be used?
if the house has no chimney or a chimney too large for a water heater
Where does the probe for the temperature/pressure relief valve sit in the tank?
in the top 6 inches of the tank
common problems found in fan assisted water heaters
inoperative; blower intake obstructed; poor venting arrangement; poor blower wiring
why may an explosion with propane be more likely than with natural gas?
propane is heavier than air and can accumulate, especially in a low area
types of traps not permitted in residential construction
s-trap; drum trap; bell trap; crown vented trap
what is the implication of a trap that is too long?
siphoning the trap
Water running out of the burner compartment on start-up of a gas water heater suggests __________.
that condensation in the combustion chamber is running down through the center of the water heater and draining out of the bottom
common leak locations in 2 piece toilets
the bowl, the tank, the seal
Why are leaks more difficult to find in drain, waste, and vent systems than in supply systems?
the pipes are usually idle and the water is not under pressure
explain why toilets don't need traps
the toilet bowl itself is a trap
describe a stop and a waste valve.
the valve shuts off the water and the drain cock drains water from the pipe
what are the functions of the 3 pipes connected to a sewage ejector pump?
the vent pipe vents sewer gases, the discharge pipe handles the waste, and the drain pipe brings the waste into the pump.
what are the 2 methods of rating a water heater?
the volume of the water it can hold and the size of the burner
Why is a check valve necessary when a sewage ejector is connected to municipal sewers?
this protects the ejector pump and house fixtures that feed the tank from backup of the municipal sewer system.
how is a mixing valve used to stop a toilet sweating?
this valve mixes hot water with the cold water at the toilet supply. this is less incentive for condensation because the warmer water used to fill the toilet won't cool the surrounding air to the dew point
what is the purpose of a venting system?
to equalize the air pressure in the waste plumbing system so that the traps won't syphon
what is the purpose of a sewage ejector pump?
to lift the waste from a toilet (and any other fixtures) below the public or private sewer line, up into the sewer. these pumps are needed when waste can't flow by gravity into the sewer system
describe a water hammer and why it occurs
water hammer is a loud banging sound in the pipes that occurs when water moving at several feet per second has to stop abruptly when a valve is turned off. the water bounces off the valve and creates a vacuum as it bounces away from the valve. the vacuum then violently attracts the water back to the low pressure area and the water again bounces off the closed valve. the effect of this is reverberation, which sounds like someone pounding on metal piping with a hammer.
How is a cross connection possible with a hose bibb? how is it prevented?
with no backflow prevention device, outside water could be sucked into the plumbing system if the hose is attached, and the supply pressure drops below atmospheric pressure. install a backflow prevention device
Do toilets need vents?
yes
Does a toilet need to have a shutoff valve on the supply line?
yes
