Watts DRAIN VALVE 3/8

02 / Required tools & 4-step mounting sequence

• +Matching threaded union or compression adapter sized to your pipe diameter (DN15 / DN20 / DN25)
• +Calibrated spanner or torque wrench for thread/union tightening without housing distortion
• +System shut-off and air-bleeding check before commissioning the circuit

1. 01 · Verify thread & nominal diameter (DN)

   Confirm that 29038 connection matches the supply/return pipework and flow direction arrow.

2. 02 · Mount the body onto the isolated branch

   Depressurise the heating circuit, fit the union tailpiece and tighten to factory torque.

3. 03 · Set hydraulic pre-setting / control parameter

   Adjust the flow scale (Kvs / l/h) or controller setting according to room or boiler loop load.

4. 04 · Pressurise, bleed air & verify tightness

   Refill the loop, vent trapped air and verify leak-free operation under operating temperature.