Tips for Opening Radiator Valves

When to Open and Close Radiator Valves During Pressure Testing

Pressure testing is a particularly important step before the official start of the heating season, and the specific timing varies depending on the requirements of local heating authorities. Generally, pressure testing should be completed in October. At this time, should residents open their radiator valves? When is the best time to do so?

1. Do not open the radiator valves at the start of pressure testing

To test whether the home’s radiators and heating equipment are functioning properly, a pressure test is conducted before the official heating season begins. It is recommended that you do not open the valves in the pipe shaft (including the supply and return valves) when the pressure test first begins, allowing the water to fully fill the main pipes. Let the water circulate through the main pipes first; this will flush out rust and impurities that have settled in the pipes. If you open the valves too early, impurities in the pipes will enter your home’s heating system, affecting heating performance.

2. Open the Valves Once Pressure Stabilizes

Pressure testing typically lasts one to two days, depending on the location. Residents should pay attention to the schedule for pressure testing in their community. If the test lasts only one day, you should open the valves that afternoon; if it lasts two days, you can consider opening the main heating valve the following morning.

How to Open the Valves?

Locate the main supply and return pipes; there are two valves on each. For valves with handles, flip the handle so it is parallel to the pipe to open it; for valves with dials, turn the dial counterclockwise until it stops.

3. Close the Valves After the Pressure Test Is Complete

Once the pressure test is complete, the heating pipes are filled with water and remain under pressure. Once you’ve confirmed that there are no leaks from the radiators in your home, you can close the valves on the supply and return pipes.

How to close the valves?

Closing the valves is the reverse of opening them. For valves with handles, turn the handle until it is perpendicular to the pipe; for valves with a wheel, turn the valve clockwise until it stops.

II. When to Open the Valves During the Official Heating Season

Heating schedules vary by city; in North China, heating generally begins in mid-November. During the period between the start of heating and the official heating season, do residents need to open the valves?

1. Do Not Rush to Open the Valves at the Start of the Heating Season

The “start of the heating season” refers to the week or so before heating begins. It is recommended that you do not rush to open the valves during this time. During the initial phase, the circulation of heating water is very fast. If you open the valves at this time, rust and impurities in the pipes will be carried into the indoor heating system, causing blockages in the filters. Impurities will also accumulate in the radiators, leading to increasingly severe blockages that impair heating efficiency. Therefore, it is not recommended to rush to open the valves during this initial phase.

2. Open the Valves After Heating Has Officially Begun

After the initial heating period—which lasts about a week—ends, the system enters the regular heating phase. At this point, open the valves, including the main valve and the inlet and outlet valves. At the same time, monitor the radiators; if any leaks are detected, address them promptly. Why is it necessary to check for leaks again? During the first inspection, the water in the pipes was cold, but after heating begins, the water becomes hot. As the water temperature rises, leaks are more likely to occur.

Once you’ve confirmed there are no leaks, keep the valves open—there’s no need to close them. At this point, hot water will circulate normally through the pipes, and the indoor temperature will become increasingly stable. After one week of operation, it’s recommended to clean the filter to remove impurities, ensuring that hot water circulates smoothly throughout the system.

The above covers the key considerations for opening and closing valves before and after the heating season begins. By operating the valves at the appropriate times, you can ensure the heating system runs normally and prevent issues such as radiators failing to heat properly.

Summary: Each year after the heating season begins, users need to open and close the valves at the appropriate times. If initial preparations are neglected due to a lack of operational experience—failing to open and close the valves at the right times or clean the filter screens promptly—debris will accumulate, leading to progressively poorer heating performance. Although the heating season is already well underway, we would still like to remind you that paying attention to these early-season operations is essential for ensuring your radiators function properly.