TriangleTube SMART Series, Installation & Maintenance Manual

3

CHAPTER

 2

CHAPTER 2 - INSTALLATION - PIPING

2.1.  Temperature & Pressure (T&P) Relief 

Valve

To reduce risk of excessive pressures and 

temperatures in the water heater, install tem-

perature and pressure protective equipment 

required by local codes, but no less than a com-

bination temperature and pressure relief valve 

certified by a nationally recognized testing lab-

oratory that maintains periodic inspection of 

production of listed equipment or materials, as 

meeting the requirements for Relief Valves and 

Automatic Gas Shutoff Devices for Hot Water 

Supply Systems, ANSI Z21.22. This valve must 

be marked with a maximum working pressure 

of the water heater.

•  Every SMART water heater must be protected with 

a T&P relief valve.

•  Determine T&P relief valve size by the following 

specifications, unless they conflict with local codes:

– SMART 30/40/50: 3/4”NPT with an AGA Rating 

of 100,000 BTU/hr and a maximum pressure rat-

ing of 150 psig. (Watts 100XL-8 or equivalent).

– SMART 60/80/100/120: 3/4”NPT with an AGA 

Rating of 200,000 BTU/hr and a maximum pres-

sure rating of 150 psig. (Watts 40XL-8 or equiv-

alent).

For proper operation of the T&P and to prevent 

the T&P from activating due to boiler water 

temperature, use a T&P relief valve with extend-

ed element. We recommended an 8” minimum 

length to ensure element senses domestic water.

CAUTION

2.1.1  Standard Installation

•  Install T&P relief valve in the 

Auxiliary

 connection 

located behind the air vent on the top of the water 
heater (Refer to 

 Fig. 2 on page 7

). 

or

•  Install the T&P relief valve in the run (straight through 

leg) of a tee located at the domestic hot water outlet 

when using the 

Auxiliary

 connection for a recircula-

tion return (Refer to 

 Fig. 3 on page 7).

2.1.2  Commonwealth of Massachusetts Installation

Follow this procedure for jurisdictions requiring a vacu-

um breaker to be installed on the domestic cold water 

inlet.

•  Install the T&P valve in the run (straight through leg) 

of a tee located at the domestic hot water outlet. 
Use a long element T&P relief valve (Refer to 

 Fig. 6 

on page 9).

2.1.3  T&P Relief Valve Discharge Piping

•  T&P relief valve discharge piping must be:

– Made of material serviceable for temperatures 

of 250ºF or greater.

– Directed so that hot water flows away from all 

persons.

– Directed to a suitable place for disposal.

– Installed so as to allow complete draining of the 

T&P relief valve and discharge line.

•  T&P relief valve discharge piping must not be:

– Excessively long. Using more than 2 elbows or 

15 feet of piping can reduce discharge capacity.

– Directly connected to a drain. Terminate discharge 

piping within 6” from drain. Refer to local codes.

– Plugged, reduced or restricted.

– Subject to freezing.

Do not install any valve between T&P relief 

valve and tank connection or on T&P relief valve 

discharge piping. Do not plug T&P relief valve 

or discharge piping. Improper placement and 

piping of T&P relief valve can cause substantial 

property damage, serious injury, or death.

WARNING

NOTICE