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LF70A-F-050 Lead Free Watts Mixing Valve. 1/2 Inch
   Model: LF70A-F-050
LF70A-F-050 Lead Free Watts Mixing Valve. 1/2 Inch
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    watts vavleWatts Mixing Valve
    LF70A-F-050 -  1/2 Inch


    Hot Water Extender Tempering Valve
    Hot Water Extender Tempering Valves are used in residential water supply applications to mix cold and hot water to extend capacity of water heater storage tanks and hot water boiler tankless heaters. 

    You can meet various installation requirements with the Watts 70A Series Hot Water Extender Tempering Valves. They are available in 1⁄2" and 3⁄4" [15 - 20mm] sizes, with sweat connections. Temperature range 120° to 160°F [49°- 71°C].

    The hydraulically-operated thermostat opens a spring loaded check in the cold water inlet allowing cold water to mix with the hot water.

    Maintenance is very simple, as the thermostat is easily removed and replaceable as a unit. Valve bodies are of brass construction that is recognized and required to resist corrosive domestic hot water conditions.

    Product Application:
    Hot water extender tempering valves are used in residential water supply applications. Recommended for tankless heater, water heater and solar installations

    Product Function:
    Adjustable temperature
    control - mixes hot with cold
    water to preset temperature.

    Product Features:
    Brass valve bodies
    Simple maintenance
    thermostat assembly
    is easily removed and
    replaceable as a unit
    "FINGER TIP" Dial
    adjustment Cap
    Stainless steel spring
    with sweat connections

    Product Warranty:
    1-Year Limited Factory Warranty - see warranty details below 

    Maximum Pressure:
    150psi [10 bars]
    Series 70A temperature range: 120°F to 160°F


    watts materials and dimensions

    Watts 70A Mixing Valve Dimensions and Weight

    HELP » Contact Customer Support
    Toll-Free help line offering product info and ordering support
    Online e-mail technical and installation support

    Installation Note:
    Valve should be installed by a licensed contractor

    Product Installation: 
    Close both hot & cold water shutoff valves upstream of the valve
    Bleed pressure from the system.
    Remove the thermostat and bonnet assembly [A], which is
    hand-tight, from body and install valve body as illustrated in
    diagram. Valve must be trapped as shown.
    Reinsert Thermostat and Bonnet assembly in body and tighten
    knurled portion of bonnet securely with pliers or channel locks.
    START UP REQUIREMENTS: Open cold water then hot water
     shutoff valves. The cold water supply line to Series 70A valve
    should always be opened first to prevent possible thermostat

    HELP » Installation Manual[PDF Format]

    Periodic inspection by a licensed contractor is recommended. Corrosive water conditions, temperatures over 210°F [99°C], unauthorized adjustments or repair could render the valve ineffective for service intended. Regular checking and cleaning of thermostat assembly helps to assure maximum life and proper product function. Frequency of cleaning depends upon local water conditions.

    Watts 70A Series Troubleshooting Guide




    Fluctuating or erratic hot water temperature at fixture. Heavy draws of either cold or hot water elsewhere in the system, such as clothes washer or dishwasher.

    Unbalanced pressures.
    Hot water temperature control valves cannot compensate for this condition. Check
    valves in hot and cold legs to hot water temperature control
    valve would help but not cure the problem.

    Install balancing or throttling valves (shutoff valves) in hot
    and cold legs to hot water extender tempering valve and
    adjust accordingly for demand.
    Hot water backing up into cold water line. Hot water pressure overriding cold pressure. Install check valve in cold water leg to hot water temperature
    control valve.
    Cannot adjust water temperature to desired temperature. Unequal pressures.

    Hot or cold temperature differential.

    Valve undersized.

    A balancing or throttling valve must be installed in the cold water leg to the hot water temperature control valve to throttle or restrict the pressure. In most installations, the cold water supply line feeds both the hot water temperature control valve and the water heater or tankless heater. To compensate for the pressure drop through the heater, the cold water to the hot water temperature control valve must be throttled or reduced.

    Check water heater controls to verify that the water temperature
    is the same as the heater thermostat setting.

    Check gpm flow required versus gpm flow capacity of valve.

    High pressure drop through hot water temperature control valve. Valve undersized. Install larger hot water temperature control valve.
    Insufficient hot water during peak demand
    Valve undersized.

    Heater or capacity insufficient for demand.
    Check gpm flow required during peak demand period and
    size hot water temperature control valve accordingly.
    Frequent failure of thermostatic element. Thermostatic element exposed to extremely high temperature.

    Corrosive water conditions. (Buildup of mineral deposits)

    Electrolysis (pitting deterioration, etc.)
    Check heater thermostat setting.
    Hot water temperature control valve must be trapped at least
    8" to 12" as per installation instructions. Install check valves
    as recommended.

    Frequent cleaning of thermostat element and plunger would
    tend to prolong the life of the element. A small coating of
    FDA approved silicone lubricant in the piston area of the
    element would also help.

    Electrically ground the piping system or install dielectric
    All hot or cold water flows at hot fixture. This problem will require considerable troubleshooting
    met. Minimum flow requirement for 70A series valves is 2 gpm.
    Verify that complete installation instructions were followed:

    Is valve properly trapped?

    Check to see if thermostatic element has failed.

    Check to see if temperature control on water heater is
    set at desired temperature.

    Check to see if minimum flow requirements for valve
    size are met. Minimum flow requirements for 70A series valves is 2 gpm.

    Watts hot water extender tempering valves cannot used for tempering water temperature at fixtures. Severe bodily injury [i.e., scalding or chilling] and/or death may result depending upon system water pressure changes and/or supply water temperature changes. A.S.S.E. standard 1016 listed devices such as watts models L111 or MMV should used at fixtures to prevent possible injury.

    The WATTS hot water tempering valves are designed to be installed
    at or near the boiler or hot water heater. They are not designed to compensate for system pressure and/or temperature fluctuations and should not be used where devices tested to S.S.E. standard 1016 are required. These WATTS valves should never be used to provide "anti-scald" or "anti-chill" service.


    Product Manufacturer: Watts Industries Inc.

    Manufacturer Warranty:
    Watts Regulator Company warrants each product against defects in material and workmanship 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. This shall constitute the exclusive remedy for breach of warranty, and the Company shall not be responsible for any incidental or consequential damages, including without limitation, damages or other costs resulting from labor charges, delays, vandalism, negligence, fouling caused by foreign material, damage from adverse water conditions, chemicals, or any other circumstances over which the Company has no control. This warranty shall be invalidated by any abuse, misuse, misapplication or improper installation of the product. The company makes no other warranties express or implied except as provided in this limited warranty.

    Processing and Delivery Information: Please allow Processing Time as stated above for your order, plus standard transportation delivery time. Orders placed after 2PM EST may not begin processing until the next business day. Please call for Rush Processing and/or Rush Shipping options.

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