Thread: Pressure/temperature relief value and line

1996 Hot water heater that has the PTR value mounted on top of the water heater. From there the drain line runs horizontal then straight up and horizontal again to the adjacent wall and out. The drain line is leaking a slow drip which seems bizarre to me since the water has to move straight up and there is no pressure unless it is full to the elbow. Any thoughts here as to this set up and the leak.


Thanks, Jim Murphy

Similar Threads:

• Copper Gas Line -
• Exterior Installation of Gas Flex Line
• vertical pipe on relief line
• black flex gas line
• New overhead line securing technique

Originally Posted by JIM MURPHY

1996 Hot water heater that has the PTR value mounted on top of the water heater. From there the drain line runs horizontal then straight up and horizontal again to the adjacent wall and out. The drain line is leaking a slow drip which seems bizarre to me since the water has to move straight up and there is no pressure unless it is full to the elbow. Any thoughts here as to this set up and the leak.


Thanks, Jim Murphy

Guess the good thing is , it's leaking, other wise it's a time bomb waiting to go off.
They needed a real plumber yesterday to repipe it properly, with proper materials.

What Dan said, plus you might want an electrician to fix that wiring.

If the valve has a slow leak it would fill the piping until it reaches a point where it can drain by gravity. It will then continue to drip from the termination at the same rate as the valve leak. Seems pretty straightforward and I don't see anything "bizarre" about it.

Thanks Richard and Dan

I suspected that the line was full of water and it was dripping as it got to a point of gravity. Owner said it has been dripping for the last six years since he moved in. He probably will not fix it until he has to or the buyer makes him.

Originally Posted by JIM MURPHY

Thanks Richard and Dan

I suspected that the line was full of water and it was dripping as it got to a point of gravity. Owner said it has been dripping for the last six years since he moved in. He probably will not fix it until he has to or the buyer makes him.

Personnaly I would refer him to the, watts relief valve web site, and or send him a link to it NOW.
Or I guess he could wait until the big boom, then not have a home to sell, not to mention the danger to his family by leaving it the way it is.

That T&P discharge and drain line also looks like it is PVC and not CPVC ... PVC is not allowed for that discharge line or drain line.

Enclosure the NM cable in flexible metal conduit where it leaves the wall (add junction box, run NM cable into junction box, leave junction box with THHW to the water heater in flexible metal conduit). Also properly secure the NM cable to the wall.

Not in any way defending that setup but his T&P and water heater may be just fine. He may have a prv or some other valve/meter assembly which creates a closed system. With this system, if the heater isn't provided with an expansion tank and the city supply has fluxuating pressures, the T&P is (sort) of doing it's job and releasing excess pressure. In that instance the correct thing would be to call for an expansion tank (and fix the piping, wiring, etc.).

Lot's of if's but the above scenario is quite common.

Originally Posted by Matt Vozzella

Not in any way defending that setup but his T&P and water heater may be just fine.

Matt,

What I think you meant to say was that the T&P VALVE "may be just fine", but you certainly are not endorsing that T&P discharge line and its routing, are you?

Originally Posted by Jerry Peck

Matt,

What I think you meant to say was that the T&P VALVE "may be just fine", but you certainly are not endorsing that T&P discharge line and its routing, are you?

Routing up, definitely not. Discharging outside may or may not be code compliant at the time of installation and to that I'm trying not to comment on.

I just wanted to make others aware that sometimes there's other reasons for the T&P to slightly discharge.

Originally Posted by Matt Vozzella

Routing up, definitely not. Discharging outside may or may not be code compliant at the time of installation and to that I'm trying not to comment on.

And the use of PVC?

I just wanted to make others aware that sometimes there's other reasons for the T&P to slightly discharge.

That part is understood.

Originally Posted by Jerry Peck

And the use of PVC?

You had that covered a couple of posts up. CPVC or copper only on the T&P.

I decided to ask my question on this thread since it is similar to one of Jerry's comments.

I have always called out PVC on TPR drains. Today's inspection has this setup (see picture). I am prepared to call it out.

However, I am wondering when I see a similar situation in, for example, a hallway closet and the drain for the water heater is piped down through the concrete. My assumption is that drain is also PVC.

I'm looking at IRC 2803.6.1 and 2904.5. I don't see anything specifically saying that PVC can't be used...I mean other than common sense.

All help is greatly appreciated and maybe one day, when I grow up, I can return the favor.

It needs to be CPVC unless specifically stamped as acceptable for that application.

do you have anything from the code book that states that?

II'm sorry, did a fast look and fast reply. Let me correct myself. It looks like the T&P is copper, correct? The indirect connection to the pan drain is incorrect. PVC is allowable in most codes for PVC

Originally Posted by JB Thompson

do you have anything from the code book that states that?

- P2803.6.1 Requirements for discharge pipe. The discharge piping serving a pressure-relief valve, temperature relief valve or combination valve shall:
- - 1. Not be directly connected to the drainage system.

- - 2. Discharge through an air gap located in the same room as the water heater.
- - 3. Not be smaller than the diameter of the outlet of the valve served and shall discharge full size to the air gap.
- - 4. Serve a single relief device and shall not connect to piping serving any other relief device or equipment.
- - 5. Discharge to the floor, to an indirect waste receptor or to the outdoors. Where discharging to the outdoors in areas subject to freezing, discharge piping shall be first piped to an indirect waste receptor through an air gap located in a conditioned area.
- - 6. Discharge in a manner that does not cause personal injury or structural damage.
- - 7. Discharge to a termination point that is readily observable by the building occupants.
- - 8. Not be trapped.
- - 9. Be installed to flow by gravity.
- - 10. Not terminate more than 6 inches (152 mm) above the floor or waste receptor.
- - 11. Not have a threaded connection at the end of the piping.
- - 12. Not have valves or tee fittings.
- - 13. Be constructed of those materials listed in Section P2904.5 or materials tested, rated and approved for such use in accordance with ASME A112.4.1.

Is the horizontal drain line from the pan?

Is the vertical black drain line from the T&P? If so, there is nothing correct about that line.

Originally Posted by Matt Vozzella

PVC is allowable in most codes for PVC

Matt,

Huh???

What you say?

Jerry,

The drain coming from the TPR is copper. It is going into the drain line in a sort of "not really, but we tried" air gap manner.

The white line is regular pvc. I too saw #13 in 2803.6.1 However, when looking 2904.5, where is the code that says no bueno on PVC?

OR

Do I base it off the ASME portion ?

Thanks

Originally Posted by JB Thompson

The white line is regular pvc. I too saw #13 in 2803.6.1 However, when looking 2904.5, where is the code that says no bueno on PVC?

J B,

This part: "13. Be constructed of those materials listed in Section P2904.5 " ...

What must the drain line be constructed of?
- Material listed in Table P2904.5.

Is PVC listed in Table P2904.5?
- Nope.

I see said the blind man. You are more versed at reading the "book" than I.

This also clarifies the difference between "service" and "distribution"

thank you.

I spoke too soon.

what does the IRC mean when they use the word distribution?

Originally Posted by JB Thompson

I see said the blind man. You are more versed at reading the "book" than I.

This also clarifies the difference between "service" and "distribution"

thank you.

Originally Posted by JB Thompson

I spoke too soon.

what does the IRC mean when they use the word distribution?

JB,

The "water service" piping is 'to the house' from its supply source, whereas "water distribution" piping is distributing that supplied water throughout the house.

Originally Posted by Jerry Peck

JB,

The "water service" piping is 'to the house' from its supply source, whereas "water distribution" piping is distributing that supplied water throughout the house.

That's what I would reasonably think. However, the next section is sanitary drainage. TPR water is not being distributed, but drained (though not in the sanitary system). So why is it included in distribution? Or should I just shut up and quit asking?

Bruce

(JB is how I registered, though now I don't know why)

Bruce,

Originally Posted by JB Thompson

However, the next section is sanitary drainage.

The first table is for water service, the second table is for water distribution, the third table is for drainage, here is why: 1) water needs to get to the building by the water service pipe; 2) water then needs to be distributed to the fixtures in the building; 3) the water used at those fixtures needs to go into the drain and ... the drainage system.

It is step-by-step: first get water, second use water, third drain water away.

The water service piping carries ... cold water ...

The water distribution piping carries ... cold water AND HOT water ... and must be rated for HOT water. You will see where this ties into the next part.

TPR water is not being distributed,

What kind of water comes out the T&P relief valve: a) cold water; b) HOT water?

but drained (though not in the sanitary system).

... while still HOT.

So why is it included in distribution?

I believe you now have that answer, right?

OK...but what's the difference in the hot water going down the drain from my dishwasher, bathtub, or kitchen sink?

I understand the difference in the temperature coming from the TPR, but people regularly pour very hot water down their sinks?

I still don't see why the TPR is included in distribution.

Originally Posted by JB Thompson

OK...but what's the difference in the hot water going down the drain from my dishwasher, bathtub, or kitchen sink?

The hot water in the T&P discharge drain line is not cooled by the air or by the fixture it is going into (the sink, dishwasher, bathtub, etc.).

I understand the difference in the temperature coming from the TPR, but people regularly pour very hot water down their sinks?

See above.

I still don't see why the TPR is included in distribution.

Would you run HOT water through a PVC pipe? If not, why not?

Originally Posted by Jerry Peck

The hot water in the T&P discharge drain line is not cooled by the air or by the fixture it is going into (the sink, dishwasher, bathtub, etc.).



See above.



Would you run HOT water through a PVC pipe? If not, why not?

Yes I understand that. I guess I'm thinking real world where yes, occasionally, people DO pour boiling water down their kitchen sink (just finished cooking some vegetable or whatever) into the pvc.

Jim, in future post you might want to rename your pic's to preserve the customer anonymity.

Originally Posted by JB Thompson

I decided to ask my question on this thread since it is similar to one of Jerry's comments.

I have always called out PVC on TPR drains. Today's inspection has this setup (see picture). I am prepared to call it out.

However, I am wondering when I see a similar situation in, for example, a hallway closet and the drain for the water heater is piped down through the concrete. My assumption is that drain is also PVC.

I'm looking at IRC 2803.6.1 and 2904.5. I don't see anything specifically saying that PVC can't be used...I mean other than common sense.

All help is greatly appreciated and maybe one day, when I grow up, I can return the favor.

Well most codes want the T&P to drain to a site drain and not tie in with any other condensate drains or pan drains at all. Here in Illinois that set up would not pass code.