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Water Heater experts??
- Thread starter aircooled
- Start date
That is not an overflow, but rather a pressure temperature valve that keeps the tank from bursting. IF you have a puddle you have a concern. Usually once those valves pop and let water out then the valve is no longer any good. At a minimum I would replace the P/T valve and keep a close eye on the unit.
GRHawk
Member
OP, this happened around here last week:
~~
An electric water heater exploded and tore through a Kannapolis house Thursday morning, city officials said. Kannapolis' fire department responded to reports of an explosion at 1856 Independence Square at about 5:45 a.m. Responders found a house with extensive damage and a water heater that had been launched nearly 70 feet from the house. Parts of the house were scattered 300 feet from the residence, city officials said. Two other houses and a vehicle also were damaged.The home was not occupied at the time of the incident, according to the city. Investigators learned the water heater was built in the 1950s and did not have a valve designed to release pressure, city officials said.
~~
I couldn't find a pic online, but the pic in the paper made the house look like a house of cards. The whole end of the house was blown off at the roofline, and leaning over. Lucky that no one was inside.
~~
An electric water heater exploded and tore through a Kannapolis house Thursday morning, city officials said. Kannapolis' fire department responded to reports of an explosion at 1856 Independence Square at about 5:45 a.m. Responders found a house with extensive damage and a water heater that had been launched nearly 70 feet from the house. Parts of the house were scattered 300 feet from the residence, city officials said. Two other houses and a vehicle also were damaged.The home was not occupied at the time of the incident, according to the city. Investigators learned the water heater was built in the 1950s and did not have a valve designed to release pressure, city officials said.
~~
I couldn't find a pic online, but the pic in the paper made the house look like a house of cards. The whole end of the house was blown off at the roofline, and leaning over. Lucky that no one was inside.
SarcasticDwarf
Diamond Member
The old water heaters were monsters and could do that. They were also far better in many ways in that it was not at all uncommon for them to last more than 30-40 years (some lasted more than twice that). The newer ones rarely last more than 10-15 years at best. I would doubt that there are many water heaters from before the 1960's left in the US.
alkemyst
No Lifer
I'd really try to bite the bullet and replace it...if you knew what you were doing and could verify the integrity of the unit it'd be different.
10 years is a good haul for a waterheater. Buying a newer one may pay itself off in savings.
A 40 gallon base unit is about $200...they come up on craigslist too sometimes.
When a water heater goes bad it can make for a extremely expensive proposition in flooding or bursting.
I'd find a way to route the pressure relief to outside for now in some way.
10 years is a good haul for a waterheater. Buying a newer one may pay itself off in savings.
A 40 gallon base unit is about $200...they come up on craigslist too sometimes.
When a water heater goes bad it can make for a extremely expensive proposition in flooding or bursting.
I'd find a way to route the pressure relief to outside for now in some way.
NoShangriLa
Golden Member
It could be time to replace the HWT because 10 year old is a bout the life time of a HWT with out annual anode replacement.
As, suggested above the Pressure/Temperature valve is the problem, therefor replace the valve is a short term fix. But, for the immediate moment, a few quick blast of water by lifting the spring loaded lever at P&T top to clear out any debris that may be the cause of the P&T failure.
I would drain a few gallons of water from the tank at the bottom hose bib, and make sure that there are no rust in the water after 1-2 second of discharge. An indication of tank failure and needed replacement if there are more than a few second of rust in the discharge water.
Lower the tank temperature is an option as a short/quick term fix. 140F is the default manufacture temperature, and it is also the recommended code temperature to prevent bacteria growth.
Shouldn't there be a floor drain near by to drain the P&T pipe into?
As, suggested above the Pressure/Temperature valve is the problem, therefor replace the valve is a short term fix. But, for the immediate moment, a few quick blast of water by lifting the spring loaded lever at P&T top to clear out any debris that may be the cause of the P&T failure.
I would drain a few gallons of water from the tank at the bottom hose bib, and make sure that there are no rust in the water after 1-2 second of discharge. An indication of tank failure and needed replacement if there are more than a few second of rust in the discharge water.
Lower the tank temperature is an option as a short/quick term fix. 140F is the default manufacture temperature, and it is also the recommended code temperature to prevent bacteria growth.
Shouldn't there be a floor drain near by to drain the P&T pipe into?
Unvented water heaters have several components:
Tank
Inlet pressure regulator
Non-return valve
Heater and adjustable thermostat
Backup-thermostat with manual reset (cuts power to heater if main thermostat fails)
Expansion space or reservoir
Pressure relief valve
Temperature and pressure relief valve
Under normal conditions the tank is pressurised by the mains water to the pressure set on the input regulator. As the water heats it expands. The NR valve prevents water in the tank back-tracking into the cold water supply or damaging the regulator.
Normally, an expansion reservoir (e.g. an air bubble at the top of the tank, or a rubber air-filler bladder) takes up the expansion.
However, if the expansion reservoir is unable to absorb the entire expansion (e.g. water too hot, regulation pressure too high, air bubble all dissolved, or bladder damaged) then the pressure will rise, and will cause the pressure relief valve to release water. This water will be a slow trickle, and will only be a gallon or so.
If the pressure valve malfunctions, or if the backup thermostat malfunctions and the water gets too hot, then the temperature and pressure valve will open. While the P valve will open just enough to release the pressure the T&P valve will open full-on when triggered and water will hose out of the tank until the temperature comes down, or the pressure comes down.
The P and T&P valves must be allowed to drain visibly into a metal drain pipe. Visible drainiage is required so that faults can be seen. The metal pipe is required because in the event of an overtemperature fault - near-boiling water (at 205 F) will be released from the T&P valve at full water pressure. This high temperature and flow-rate will melt or weaken plastic pipes, unless specially rated for water heater drainage use.
The reason for 4 seperate fail safes is because of the risk of steam explosion. If steam pressure was allowed to build up until tank rupture; an exploding tank can easily demolish an entire house.
If your tank is of the air bubble expansion type, then replenishing the air bubble may solve the problem. The service manual will have instructions on how to do this - it usually involves draining the tank down a bit, and then manually opening the T&P valve to allow the tank to suck in air.
If the tank is old (over 10 years), and doesn't have dual protection valves, then it would be sensible to replace it, especially as cheap copper tanks have only a relatively short life.
Tank
Inlet pressure regulator
Non-return valve
Heater and adjustable thermostat
Backup-thermostat with manual reset (cuts power to heater if main thermostat fails)
Expansion space or reservoir
Pressure relief valve
Temperature and pressure relief valve
Under normal conditions the tank is pressurised by the mains water to the pressure set on the input regulator. As the water heats it expands. The NR valve prevents water in the tank back-tracking into the cold water supply or damaging the regulator.
Normally, an expansion reservoir (e.g. an air bubble at the top of the tank, or a rubber air-filler bladder) takes up the expansion.
However, if the expansion reservoir is unable to absorb the entire expansion (e.g. water too hot, regulation pressure too high, air bubble all dissolved, or bladder damaged) then the pressure will rise, and will cause the pressure relief valve to release water. This water will be a slow trickle, and will only be a gallon or so.
If the pressure valve malfunctions, or if the backup thermostat malfunctions and the water gets too hot, then the temperature and pressure valve will open. While the P valve will open just enough to release the pressure the T&P valve will open full-on when triggered and water will hose out of the tank until the temperature comes down, or the pressure comes down.
The P and T&P valves must be allowed to drain visibly into a metal drain pipe. Visible drainiage is required so that faults can be seen. The metal pipe is required because in the event of an overtemperature fault - near-boiling water (at 205 F) will be released from the T&P valve at full water pressure. This high temperature and flow-rate will melt or weaken plastic pipes, unless specially rated for water heater drainage use.
The reason for 4 seperate fail safes is because of the risk of steam explosion. If steam pressure was allowed to build up until tank rupture; an exploding tank can easily demolish an entire house.
If your tank is of the air bubble expansion type, then replenishing the air bubble may solve the problem. The service manual will have instructions on how to do this - it usually involves draining the tank down a bit, and then manually opening the T&P valve to allow the tank to suck in air.
If the tank is old (over 10 years), and doesn't have dual protection valves, then it would be sensible to replace it, especially as cheap copper tanks have only a relatively short life.
MikeyIs4Dcats
Lifer
yup...get a new one....not worth the risks