How to Replace an 8mm Thermostatic Radiator Valve

Written by carl pruit
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Replacing the 8mm thermostatic radiator valve is very similar to changing radiator valves of other sizes. The radiator valve is used to regulate the amount of water sent through the radiator. The thermostatic radiator valve is attached to the side of the radiator with a spud connector and is connected to galvanised piping that runs through the flooring. You can remove and replace the radiator valve in about an hour or two.

Skill level:
Moderately Easy

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Things you need

  • Garden hose
  • Pipe wrench
  • Spud wrench
  • Thread sealant
  • Single-strand wicking
  • Piping dope
  • Drill
  • Sensor wire
  • Sensor
  • Screws
  • Screwdriver

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  1. 1

    Shut off the water supply to the radiator and attach a garden hose to the drain valve on the radiator. Place the other end of the garden hose in the tub or yard where you can drain the water safely.

  2. 2

    Open the drain valve and let the radiator drain out completely. Shut the drain valve once the radiator is empty and remove the garden hose.

  3. 3

    Loosen the spud connector that secures the 8mm thermostatic radiator valve to the radiator tank with a pipe wrench until the nut is free of the threads on the tank. Turn the thermostatic radiator valve with a pipe wrench until it comes off the galvanised pipe leading from the floor and discard the old radiator valve.

  4. 4

    Remove the old spud connector from the end of the radiator tank with a spud wrench and discard the connector. Place thread sealant around the threads of the new spud connector and apply single-strand wicking to the threads of the connector.

  5. 5

    Attach the new spud connector to the radiator tank with a spud wrench and apply a layer of piping dope and single-strand wicking to the threads on the galvanised pipe coming from the floor. Fasten the new 8mm thermostatic radiator valve to the galvanised pipe with a pipe wrench and place a layer of pipe sealant to the exposed end of the spud connector.

  6. 6

    Secure the thermostatic radiator valve to the spud connector with a pipe wrench. Drill a hole in the side of the radiator cover near the top with a drill and feed the sensor wire through the hole in the cover.

  7. 7

    Attach the sensor to the outside of the radiator cover with screws. Attach one end of the sensor wire to the sensor and the other end to the top of the 8mm thermostatic radiator valve.

  8. 8

    Turn the water supply back on for the radiator tank and place the tank cover back over the radiator.

Tips and warnings

  • To avoid burns, be careful when draining the hot water out of the radiator system.

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