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Thermostatic Cartridge Calibration Instructions for 3/4" Exposed Thermostatic Shower System

The thermostatic mixing valve cartridge mixes hot water and cold water to maintain a preset water temperature. The thermostatic cartridge provides comfort and safety, because it maintains the water temperature to a preset temperature, even if there is a sudden decrease in the cold water pressure, to prevent scalding from excessively hot water.

Thermostatic cartridges may be calibrated to set the water temperature range and the maximum water temperature.

Temperature Setting and Adjustments

Calibration is the simple process by which you control the temperature range of mixed water. The Coventry Thermostatic Valve has been factory tested and calibrated to preserve its anti-scald feature when installed in your home. If you desire a hotter or colder temperature range, you can recalibrate the valve after installation, when both HOT and COLD lines are 100% operational, and all installation debris have been flushed from the water lines and the valve body. The factory has preset the valve at 110 F maximum. You may feel a 2 or 3 degree variance but turning the temperature handle will be the simple way to change the temperature.

Calibrating Temperature Setting

The Coventry valve has been factory calibrated to allow a maximum water temperature of 110 F to be set. This is an important safety feature. In some circumstances, and after the thermostatic cartridge has been removed for servicing, it will be necessary to recalibrate the valve. It is important that this calibration is carried out properly to preserve the anti-scald function of the valve.

Calibration is nothing more than the proper mixture of hot and cold water that is entering the valve. The proper mixture is nothing more than the bather’s perception of a proper shower. When we calibrate we simply adjust the incoming hot and cold water to a normal balance so that the bather has a comfortable and secure shower.

Begin by unscrewing the Coventry button in the center of the temperature control knob with your thumb and forefinger, as shown in the figure below. Then use a large screwdriver to loosen and remove the large screw in the center which secures the handle onto the thermostatic cartridge (see figure). When the screw is removed, turn the cartridge slightly counterclockwise to increase the maximum temperature, or slightly clockwise to decrease the maximum temperature. Push the handle back on and check water tempera- ture. Remount the handle, tighten the large screw into the center of the handle and then tighten the Coventry button. Under no circumstances is the thermostatic cartridge to be dismantled. Doing so will VOID THE WARRANTY and possibly make the cartridge inoperable.

  1. Reviewing the figure above, the diagram shows how to remove the Coventry white ceramic button. This button is installed simply using your finger and thumb to remove or install the button.
  2. You will need a large screwdriver. Do not attempt this with a small screwdriver as brass is soft and you will strip the head out of the screw, therefore making it difficult to re-secure the handle body in place.
  3. Now, look at the handle body. If you remove it you will notice that built inside as an integral part of the body is a stop. This stop is important because depending on how you line it up on the stop, shown down on the body, you may or may not be able to adjust the handle for its full range of motion. The exploded view is important and it’s simple. It gives you a visual point of view on how all the parts go together and come apart.
  4. After you have removed the button and have used a large screwdriver to remove the center screw holding the handle onto the assembly, the next step is to actually run the water so you can set the range of temperature for your convenience. When the water is running, turn the center of the thermostatic cartridge as shown. For colder water rotate the cartridge clockwise. For warmer water rotate the cartridge counterclockwise only slightly in either direction.
  5. After you have balanced the hot side and cold side while the water is running, you will determine whether this is the proper water temperature for your shower. We recommend that it be only slightly hotter than what you would shower at, so you can turn the handle after it is reinstalled to a cooler or hotter temperature.
  6. Reinstall the handle so that the integral stop inside the sleeve lines up to the left side of the stop on the body. Rotate the handle counterclockwise until it hits the stop point.
  7. In this position, reinstall the center screw (with the large screwdriver), tighten securely, and check this temperature setting. When complete you will have set the maximum temperature for this valve.
  8. Now rotate this temperature handle with the water running 2 or 3 times. You will see how simple it is to increase or decrease your bathing water temperature.
  9. Reinstall the center cap using your thumb and forefinger and you are ready to take a safe, secure and comfortable shower.