Accessory: Thermostatic Balancing Valve

The Thermostatic Balancing Valve (-TBV) in conjunction with MV17 Series Master Mixing Valves assists in making necessary temperature adjustments on Supply Fixtures and Command Stations.

This valve thermostatically adjusts the amount of return water that is reheated, eliminating the usual trial-and-error process and automatically balancing heat loss/heat gain to prevent temperature creep. It is intended for use with relatively low recirculated flows.

The MV17 and the -TBV valves are factory set to 120°F (48.89°C) and 110°F (43.33°C) respectively. If the temperature of the mixing valve is not changed, the -TBV should be factory set to maintain your loop temp at 110°F (43.33°C).

If the mixing valve has been adjusted up or down, the -TBV will need to be adjusted accordingly. Adjustments can be made in approximately 10°F (5.55°C) increments/decrements by rotating the -TBV stem one full turn counterclockwise or clockwise, respectively. Be sure to allow enough time for the loop to change temperature and stabilize before readjusting.

Adjustment:

If the valve gets out of adjustment and you’re not sure what the current setting is, use the following instructions to reset.

1. Set -TBV to full cold by turning the locknut counterclockwise to loosen and using an Allen wrench to turn the adjustment stem clockwise.
2. Make sure the master mixing valve is set and the final fixture is supplied with the required temperature. After verifying the final fixture’s temperature, turn off all fixtures. While adjusting the -TBV there should be little to no system draw/usage. This will provide the best results.
3. Open the ball valve and turn on the recirculation pump. Ensure the pump is sized to meet the minimum flow of the master mixing valve and to meet the heat loss of the recirculation loop during periods of low/no system demand.
4. Monitor the thermometer. Wait for tempered water to recirculate through the facility and for the temperature to stabilize.
5. While holding the boiler return pipe, slowly rotate the adjustment screw counterclockwise until you feel the warm water begin to flow through the return to the boiler line. Stop rotating the screw.
6. Monitor the return temperature, allowing enough time for it to stabilize. If the return temperature is too hot or too cold, rotate the adjusting stem clockwise or counterclockwise as needed. When making these adjustments, assume one revolution of the adjusting stem will change the set temperature by 10°F (5.55°C) and wait for the gauge to show the changes. Ideally, the return temperature should be set from 5–15°F (2.78–8.33°C) less than that of the master mixer.
7. At this point -TBV is set. Secure the adjustment screw by turning the locknut clockwise until tight.
8. Over the next 24 hours, monitor and ensure the return temperatures are being maintained under both low and normal system draw/demand.

NOTE: The return temperature is affected by the master mixing valve outlet temperature. If the master mixer is not at the operating temperature, controlling poorly, or if the total system flow rate (pump flow and/or usage) is less than required by the master mixer, the performance of the -TBV will be affected and the observed return temperatures will fluctuate.