Is it ok to have a bucket under temperature/pressure relief valve, rather than draining outside?

Users who are viewing this thread

Sbas

Member
Messages
48
Reaction score
2
Points
8
Location
eugene
Hi guys,

I am waiting to get my 30 gallon electric water heater installed. It is placed inside my bathroom , right next to the shower.

I really want to avoid running the t and p valve through my floor or outside the wall, so am wondering if it is safe/common to just place a bucket underneath? According to this lowes tutotorial, it is : https://www.lowes.com/projects/repair-and-maintain/install-an-electric-water-heater/project

I have a few questions regarding that
1) How often does the t/p valve drain and how much water is expected? In other words, is a 5 gallon bucket more than enough as long as I empty it regularly? Or is there a chance more than 5 gallons at once will come out of valve?
2) I will have an expansion tank. Will that help with minimizing the amount of water dripped from the valve?
3) Does water ever drip out of the drain valve or is that simply there just o drain the tank manually?

On a side note, the plumber I was going to get out here (who has been a plumber for 30 years) said "to tell you the truth, I don't really know why they use expansion tanks...I just install them". Seemed a bit odd to me. Should I not use him?

Oh and regarding any codes, I live in a tiny house on wheels, a bit off grid so this does not come into effect here.

Thank you!
 

Reach4

Well-Known Member
Messages
38,798
Reaction score
4,412
Points
113
Location
IL
Around here, letting it spill onto the floor is allowed. However I suspect it is not technically legal to have the pipe go into a bucket. A pan underneath where the rim is an inch lower than the bottom of the pipe would be fine.

They rarely leak. You might consider an alarm to alert you.

With no expansion tank, they may dribble.

On a side note, the plumber I was going to get out here (who has been a plumber for 30 years) said "to tell you the truth, I don't really know why they use expansion tanks...I just install them". Seemed a bit odd to me. Should I not use him?
No reason to avoid him.
 

Sbas

Member
Messages
48
Reaction score
2
Points
8
Location
eugene
Hey Reach, thanks for the quick response. What do you mean around here it is allowed? haha. WHy would anyone want to flood their floor?

Considering lowes is a National company, I assume their tutorial video wouldn't show something that is not legal?

What kind of alarm do you have in mind? How would that work?
 

Reach4

Well-Known Member
Messages
38,798
Reaction score
4,412
Points
113
Location
IL
Considering lowes is a National company, I assume their tutorial video wouldn't show something that is not legal?
Those practices are not national I think.

What kind of alarm do you have in mind? How would that work?
You can extend out the sensor part to reach into your plastic tub. If you use a metal tub, you would want plastic separating the sensor electrodes from the metal so you don't get a false alarm.

Basement Watchdog Battery-Operated Water Alarm-BWD-HWA
Water-Alarm-sensor-location-300x180.jpg


You can
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,770
Reaction score
1,190
Points
113
Location
New England
The T&P valve should NEVER open in normal operations. It is a safety device that opens if the pressure gets higher than 150psi, or the temperature of the water gets above 210-degrees...neither of which should really happen, but if they do, they could be quite dangerous.

But, if you have a closed water supply system, since water doesn't compress, when the WH raises the incoming cold water after use, that water does expand and rapidly increases the pressure until something leaks...if it gets to 150psi (easy if nothing else in the house is leaking), the T&P valve will open to relieve it. A properly setup and working expansion tank will prevent the pressure rising, giving that expanding water a place to go.

If you're worried about it opening and flooding things, look into a WAGS valve. It will shut the incoming water off if the water rises in the pan. Totally mechanical, no maintenance, one-time use.

http://wagsvalve.com/

https://www.taco-hvac.com/uploads/FAQ_attachments/wagsvalveins.pdf
 
Last edited:

MACPLUMB

In the Trades
Messages
1,080
Reaction score
83
Points
48
Location
HOUSTON, TEXAS
Like was posted above your T&P valve is a safety brake like on your car, it is deigned to open if the primary
thermostat fails then it is going to "DUMP" 20 or more gallons of SUPER HOT STEAMY water out do you thank a 5
gallon bucket on the floor next to your tub is the right place or outside,
Yes you need a Thermal Expansion tank as noted above
 

Terry

The Plumbing Wizard
Staff member
Messages
29,942
Reaction score
3,459
Points
113
Location
Bothell, Washington
Website
terrylove.com
My preference is to always pipe the T&P outside. When that's not possible, they let you place a bucket under it.
Normally, the T&P should never let water out. If there is a problem though, it's a life saver. A water heater can go right through the roof is pressure is too much. I see that Lowes like to wrap tape on everything. Almost all the places they say to do it, you don't. Who writes that stuff for them?
 

Sbas

Member
Messages
48
Reaction score
2
Points
8
Location
eugene
@jadnashua - Thanks for writing. So Let's say the temp does get above 210 degrees. Does the water just continue to flow out until you turn water supply off? Or would it just let out a gallon of water or so? If that IS the case, what scenarios would cause the water heater to have water flow out the relief valve indefinitely until it's shut off?

Also - is there any benefit to a closed water system? I have this water inlet https://www.amazon.com/JR-Products-160-85-Black-Flange/dp/B00KNB6EUG that has a check valve. So I assume that makes it closed? Basically, I just screw in a potable water hose into it to get my water.

@MASTERPLUMB777 - Just so I make sure the plumber installs the expansion tank correctly, is there any important things to look for? Does it connect to the hot or cold water line?

@Terry - So Let's so I do drill a hole through my floor for the relief valve to drain. Won't I still have to worry about other leaks from the drain valve or anything?

Thank you all for the advice!
 

Terry

The Plumbing Wizard
Staff member
Messages
29,942
Reaction score
3,459
Points
113
Location
Bothell, Washington
Website
terrylove.com
The expansion tank goes on the cold.
I plumb my relief lines to the outside. They don't leak water unless the pressure is too high, the temperature is too high, or the spring is old and worn.
Most of the time, they never let any water out. If they do leak water out, I prefer it's to the outside.
 

MACPLUMB

In the Trades
Messages
1,080
Reaction score
83
Points
48
Location
HOUSTON, TEXAS
the reason to go though the wall and not the floor is so that you see it and are aware of a problem,
if the T&P opens on high pressure when it gets below 150 lbs it will close on the other hand it it
opens on high temperature it will flow till enough hot water releases and cold water takes it place to cool the tank,
and the temperature probe cools enough, until the problem starts again or you correct the problem
 

Sbas

Member
Messages
48
Reaction score
2
Points
8
Location
eugene
@MASTERPLUMB777 I do have a unique situation though. I am on a steel trailer 2 feet off the ground. So the valve would go through the floor but you would be able to see it come out the bottom of the trailer (because it is 2 ft above the ground). Does that still work?
 

MACPLUMB

In the Trades
Messages
1,080
Reaction score
83
Points
48
Location
HOUSTON, TEXAS
Not unless you plan on sticking your head down everyday to look if it is dripping ! It is not just knowing
the codes but the reason behind them, it MUST be in plain sight so easily noticed,
I have seen when people ran the drain though a hole in the floor where they did not know it was leaking
because I would get a call that they had no or little hot water and found that the T&P was leaking
away under the floor where nobody could see it,
also the other reason is even though the trailer has a steel frame the wood will rot and mildew with
the excess moisture !
 

Jadnashua

Retired Defense Industry Engineer xxx
Messages
32,770
Reaction score
1,190
Points
113
Location
New England
As to how much water could be released if the temp set it off...hard to say. If the aquastat, thermostat, or burner was defective, it could just cycle as the valve opened to cool things off, then it got hot again, and opened. How high is up? Unless the valve sticks, once the 'problem' goes away, it should close - aka, automatic reset, if you will. How much would also depend on how cold the inlet is, and how big the burner or elements are.
 

Sbas

Member
Messages
48
Reaction score
2
Points
8
Location
eugene
@MASTERPLUMB777 Oh I would definitely see it if water was coming out. It's very visible and I would see it just as easy as if it came out through wall.

Why would the floor rot if the pipe is ran through the floor and comes out past the bottom of the trailer? There would be just as good as chance of the wall rotting than the floor?
 

Reach4

Well-Known Member
Messages
38,798
Reaction score
4,412
Points
113
Location
IL
@MASTERPLUMB777
Why would the floor rot if the pipe is ran through the floor and comes out past the bottom of the trailer? There would be just as good as chance of the wall rotting than the floor?

I expect that the presumption was that you would have skirting on your trailer for energy saving or other reasons. With skirting, the water down there would make for very high humidity.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks