Some reductions are not very pleasant like a reduction in pay or benefits, not good. A reduction in your weight, now there's a reason to be happy. Most things are made not to modified or reduced. If they are designed to be altered there are specific guidelines that are to be followed when making an alteration. Yet I find all manner of creative, not right, modifications to stuff all the time.

Lately I have run into more than a few water heater TPR (Temperature Pressure Relief) valve discharge line modification. The installation requirements of these pipes are pretty straight forward. Here is a warning from the Watts Company a manufacturer of these valves.

WARNING: To avoid water damage or scalding due to valve operation, discharge line must be connected to valve outlet and run to a safe place of disposal. Discharge line must be as short as possible and be the same size as the valve discharge connection throughout its entire length. Discharge line must pitch downward from the valve and terminate at least 6" (152mm) above a drain where any discharge will be clearly visible. The discharge line shall terminate plain, not threaded. Discharge line material must conform to local plumbing codes or ASME requirements. Excessive length over 30' (9.14m), or use of more than four elbows or reducing discharge line size will cause a restriction and reduce the discharge capacity of the valve.

This is fairly simple to understand. This information is printed on the yellow tag attached to the valves. See the tags in both water heater photos?

Does anyone read these tags???

The second photo shows a discharge pipe plumbed up, a no no, and has just in the picture alone 3 elbows. There were two more elbows on the pipe for a total of 5. Another no no.

Why all the fuss over a pipe and valve? Simply water heaters can become bombs. I have talked with more than a few people who seem to have a bit of dificulty in believing that a water can cause massive destruction.

In the last picture the devastation you see was caused by a 5 gallon water heater that blew up in a Massachuetts school. The average size water heater in most homes is 40 gallons.

Suspected causes for the blast were;

"Additionally several elements of the (TPR) valve were missing either by the force of the blast or they were removed prior to the blast by untrained personnel at the school."

What may have occurred, all though this was not established conclusively, was the water heater was leaking or malfuctioning and someone modified the unit which led to the explosion.

As I said most things are not designed to be modified or altered.

One more thing regarding TPR valves. If you ever see yours leaking do not open the valve.  This can cause a sudden release of super hot steam or worse an explosion if the water heater is in an over temperature state.

The best thing to do before something like this occurs is to learn how to shut your water heater down in an emergency. If you see the valve leaking immeadiately shut down the unit and then call a licensed plumber to check out the cause of the problem and repair it.

Reduction and modifications are best left for our tummies.

James Quarello
NRSB #8SS0022
JRV Home Inspection Services, LLC

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