Watts N30 User Manual

Relief Valves

Diaphragm Actuated

Pressure Relief Only: Types N30, N30L

Installation Instructions

Pressure is common to all parts of a system so valve may be installed in either hot or cold water line but as near as possible to tank or heater. Run the drain pipe to open ﬂ oor drain, never outside the building. Never install a valve of any kind in the drain line or obstruct in any way. The maximum set pressure is stamped on the valve body. Valves should be ordered to relieve not less than 25-30 lbs. above the maximum service main pressure but never above the maximum allowable working pressure of tank.

IS-N30

These valves protect against excessive pressure only. To prevent excessive temperature above

212°F, which might result in a hot water explosion, combined temperature and pressure protection is

essential. WATTS Combination Temperature and Pressure Relief Valves below give this protection.

IMPORTANT

Temperature and Pressure Relief: Types M31SL, M31XL

Installation

Combination temperature and pressure relief valves with extension thermostats must be installed so that the temperature-sensing element is immersed in the water within the top 6" (152mm) of the tank. They must be installed either in the hot outlet service line or directly in a tank tapping. Combination temperature and pressure relief valves that do not have extension elements must be mounted directly in a tank tapping located within the top 6" (152mm) of the tank. They shall be adequately insulated and located so as to assure isolation from ﬂ ue gas heat or other ambient conditions that are not indicative of stored water temperature. To avoid water damage or scalding due to valve operation, drain pipe must be as short as possible and be the same size as the valve discharge connection throughout its entire length. Drain line must pitch downward from the valve and terminate at least 6” (152mm) above the ﬂ oor drain where any discharge will be clearly visible. The drain line shall terminate plain, not threaded, with a material serviceable for temperatures up to 250°F (121°C) or greater. Excessive length, over 30’ (9.14m), or use of more than four elbows can cause a restriction and reduce the discharge capacity of the valve. No shutoff valve shall be installed between the relief valve and tank, or in the drain line. Valve lever must be tripped at least once a year to insure that waterways are clear. This device is designed for emergency safety relief and shall not be used as an operating control.

Correct Installation of T&P Relief Valves

For Heaters With Direct

Top Tapping

Max. 6”

(152mm)

Always use an extension type thermostat T&P relief valve which permits the end of the thermostat to extend into the top 6” of the tank.

For Heaters With Direct

Side Tapping

Isolation

For internal ﬂ ue heaters, a T&P relief valve with a short or standard length thermostat can be used. For external ﬂ ue heaters, see below.

Max

152 mm

Max. 6”

(152mm)

“Alternate” Only when the

tappings are not provided

Max. 6”

(152mm)

No. N30 without lever No. N30L with lever

No. M31SL

IMPORTANT: A relief valve functions, in an emergency, by discharging water. Therefore, it is es-

sential that a discharge line be piped from the valve in order to carry the overﬂ ow to a safe place of disposal. The drain pipe must be the same size as the valve outlet, and must pitch downward from the valve.

No. M31XL

NOTE: Product information is subject to change without notice

and supersedes all previous publications.

Limited Warranty: Watts Regulator Co. (the “Company”) warrants each product to be free from defects in material and workmanship under normal usage for a period of one year from the date of original shipment. In the event of such defects within the warranty period, the Company will, at its option, replace or recondition the product without charge.

THE WARRANTY SET FORTH HEREIN IS GIVEN EXPRESSLY AND IS THE ONLY WARRANTY GIVEN BY THE COMPANY WITH RESPECT TO THE PRODUCT. THE COMPANY MAKES NO OTHER WARRANTIES, EXPRESS OR IMPLIED. THE COMPANY HEREBY SPECIFICALLY DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

The remedy described in the first paragraph of this warranty shall constitute the sole and exclusive remedy for breach of warranty, and the Company shall not be responsible for any incidental, special or consequential damages, including without limitation, lost profits or the cost of repairing or replacing other property which is damaged if this product does not work properly, other costs resulting from labor charges, delays, vandalism, negligence, fouling caused by foreign material, damage from adverse water conditions, chemical, or any other circumstances over which the Company has no control. This warranty shall be invalidated by any abuse, misuse, misapplication, improper installation or improper maintenance or alteration of the product. Some States do not allow limitations on how long an implied warranty lasts, and some States do not allow the exclusion or limitation of incidental or consequential damages. Therefore the above limitations may not apply to you. This Limited Warranty gives you specific legal rights, and you may have other rights that vary from State to State. You should consult applicable state laws to determine your rights. SO FAR AS IS CONSISTENT WITH APPLICABLE STATE LAW, ANY IMPLIED WARRANTIES THAT MAY NOT BE DISCLAIMED, INCLUDING THE IMPLIED WARRANTIES OF

MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE LIMITED IN DURATION TO ONE YEAR FROM THE DATE OF ORIGINAL SHIPMENT.

Water Safety & Flow Control Products

Canada: 5435 North Service Rd., Burlington, ONT. L7L 5H7; www.wattscanada.ca

USA: 815 Chestnut St., No. Andover, MA 01845-6098; www.watts.com