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Series TWH Tankless Water Heaters

Replace that bucket of fittings and all those potential leaks associated with typical tankless water heater shutoffs. Watts’ new Series TWH Tankless Water Heater Valves replace four unions, three tees, seven nipples, two ball valves, two boiler drains and two hose bib covers used in typical tankless water heater installations. That’s up to 18 fittings and 16 connections! Watts Series TWH valves provide a clean, professional installation and ease of service.


  • Full port, quarter-turn ball valves with color-coded tee handles for fast water heater isolation
  • Quarter-turn purge and drain valves with hose bib connections and tethered brass caps
  • Includes integral ¾ in. (20mm) FPT relief valve port in hot water supply valve
  • Dielectric unions for easier service and installation flexibility
  • Integral purge and drain valve for convenient water heater draining and for simplifying water heater flushing operations
  • Unions for fast installation and removal of tankless water heater
  • Full-port ball valve design never compromises relief valve operation
  • Same-plane relief valve port/drain valve permits installation in tight spaces
  • Available with or without integral spring check valve in cold water valve
  • RV (relief valve) model include 3L 150psi (10.3 bar) pressure relief valve

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Additional Information

Danger – Scalding Lurks!

Every year, thousands of people suffer serious thermal shock or scalding injuries in their bathtubs, sinks and showers.

Click here for informative resources to help you protect against these dangers.

Learn About

Thermostatic Mixing Valves

Every year thousands suffer injuries as a result of hot water scalding and thermal shock injuries. Thermostatic mixing valves protect against these dangers.

To learn more about thermostatic mixing valves and how they work, click here.