water heater

[Anonymous]

The diagram in the instructions for my new water heater shows a "heat trap" in the outlet side of the water heater plumbing. My old one doesn't have this heat trap. What's it for and do I really need to plumb it this way?

[Wgoodrich]

Are you talking about a temperature relief valve or pressure relif valve or a cold water inlet mixing valve for commercial use?

Not sure what you are calling a heat trap.

Wg

[Anonymous]

This "heat trap" is shown in the typical installation diagram in the water heater manual. (diagram can be seen online at mfg web site if ok to put URL here) The hot water supply line immediately downstream from the union and water heater outlet is shown turning 90 degrees downward for a minimum 6" before going horizontal again. This is labled in the diagram: "heat trap/6" min." Is this functionally important or an energy conservation feature?

[imported_trinitro]

I've never seen anything that you're describing, and I've seen a lot of water heaters...
I'm guessing it's an energy conservation issue.

[Wgoodrich]

Guest by all means include the URL you mentioned. This URL may shed light on a lack of ability to pick up on what you are talking about. While we don't wish for advertising on our forum we do welcome links that inhance communication or education on the subject being discussed. We will be watching for the URL.

This strikes me to be a commercial water heater but not sure at this time.

Curious

Wg

[Anonymous]

go to: http://www.rheem.com/dealers/resourceLibrary.asp?displayNode=9

then select PDF 270k under the type/size column opposite the Rheem Standared model (4th one down from the top of the list)

this will open a .pdf file and display the Residential Electric Water Heater USE & CARE MANUAL with installation instructions for the contractor

Scroll down to page four and refer to Figure 2. - Typical Installation

[Wgoodrich]

The 6" is referring to the temperature relief valve often found to be a combined pressure and temperature relief valve.

The installation you are seeing is showing the cold water pipe to come to the water heater down 6" below the 6" heat area inside the water heater. This is not necessary to have the offset cold water pipe incoming to the tank to be 6" low if you are using the most commonly used combination temperature and pressure relief valve. Look at this combination temp / press relief valve and you should see the temp senser to extend beyond the relief valve so that valve temp sensor is at teh 6" temp sensing location. See the following copied section of the 2000 IRC pertaining to what you are speaking of. The reason we were unknown as to what you were talking about is because this comb press / temp relief valve does what the offset pipe did decades ago. Many people have only used the combo temp / press relief valve with no other concerns of the 6" mentioned due to the design of the valves being installed took care of that 6" concern as it still does today.

COPIED SECTION OF THE IRC 2000

P2803.4 Temperature relief valves.Temperature- relief valves shall have a relief rating compatible with the temperature conditions of the appliances or equipment protected. The valves shall be installed such that thetemperature- sensing element monitors the water within the top 6 inches( 152 mm) of the tank. The valve shall be set to open at a maximum temperature of210
F(99
C).

P2803.5 Combinationpressure/ temperature relief valves. Combinationpressure/temperature- relief valves shall comply with all the requirements of separate pressure- andtemperature- relief valves. P2803.6 Installation of reliefvalves. Acheck or shutoff valve shall not be installed in the following locations: 1. Between a relief valve and the termination point of the relief valve discharge pipe; 2. Between a relief valve and a tank; or 3. Between a relief valve and heating appliances or equipment.

Hope this helps

Wg

[Anonymous]

your info seems to adequately answer my question.

But note that the 6" offset is shown on both the cold water supply AND hot water delivery sides of the water heater.

And the RELIEF VALVE installation instructions on page 3 of the USE AND CARE MANUAL specifically say that "A new combination temperature and relief valve, complying with the Standard for Relief Valves and Automatic Gas Shutoff Devices for Hot Water Supply Systems, ANSI Z21.22, must be installed ...". The Typical Installation diagram on page 4 also refers to this valve specifically as a T&P type.

Anyway, a new T&P valve comes packaged with the water heater, so one would be nuts to install the old T&P valve. Should one be nuts enough to re-plumb the cold water supply and hot water dlivery sides of the water heater with 6" offsets?

[Wgoodrich]

I do not see this 6" offset in the field at construction sites.

While heat rises and dropping the pipes down as it is shown may help to limit the metal water pipes being used as a chimney coveying heat loss out of the water heater. Yet even if you had the 6"drop in the metal water pipes the heat loss would still be there by conveyance through the water itself that is in the pipes regardless if the 6" drop was there or not. I see little advantage of this 6" drop in the pipes as spoken above. Normally it is not done in the field.

Now it is your decision what you want to do.

Good Luck

Wg