Lochinvar Boiler Blocked Anti Cycling: Troubleshooting Tips.

The Lochinvar boiler may display a “Blocked” message on the screen, indicating a potential issue with the system. This could be caused by loose wiring connections, a blocked drain switch, or a significant drop in the inlet water temperature.

It is important to check the wiring connections, replace any faulty components, and ensure the inlet water temperature is within the appropriate range to resolve this problem.

Lochinvar Boiler Blocked Anti Cycling

Common Issues With Lochinvar Boiler

When it comes to the Lochinvar boiler, there are a few common issues that users may encounter. These issues include potential risks such as carbon monoxide poisoning, symptoms of a blocked heat exchanger, and reasons for boiler lockout. Understanding these common issues is crucial for maintaining the safety, efficiency, and proper functionality of the Lochinvar boiler.

Recalled Condensing Boilers Due To Co Risk

Lochinvar has recalled condensing boilers due to the risk of carbon monoxide poisoning. This hazard arises from the potential cracking of the boiler’s flue collector following a high impact event in the burner chamber. This, in turn, can lead to the emission of carbon monoxide, posing a severe risk of carbon monoxide poisoning to individuals using the boiler.

Symptoms Of A Blocked Heat Exchanger

The symptoms of a blocked heat exchanger may include inconsistent water temperature, reduced hot water supply, unusual noises, rapid pressure increase, and failure of radiators to heat up. Recognizing these symptoms is crucial for identifying the underlying issue with the Lochinvar boiler and taking appropriate measures to address the problem.

Reasons For Boiler Lockout

The boiler may experience lockout due to various reasons, such as gas supply or ignition failure. This could be attributed to blockages in the flue, a faulty gas valve, or issues with the ignition lead. Seeking assistance from a qualified engineer is essential for resolving these issues and safely resetting the boiler to ensure its proper functioning.

Understanding Anti-cycling And Blocked Status

The Lochinvar boiler may experience a blocked anti-cycling status, which can indicate issues such as loose wiring connections, blocked drains, or a drop in the inlet water temperature. Symptoms may include inconsistent water temperature and reduced hot water supply. It’s important to troubleshoot and address these issues to ensure optimal boiler performance.

Causes Of Lochinvar Boiler Anti-cycling

One common issue faced by Lochinvar boilers is anti-cycling, which can cause inefficiencies and decrease the lifespan of the boiler. Anti-cycling is not a fault but rather a status indication provided by the boiler. Understanding the causes of anti-cycling is crucial for troubleshooting and resolving the issue efficiently.

Corrosion And Wiring Issues

Corrosion at the wiring connections is one of the leading causes of anti-cycling in Lochinvar boilers. When there is corrosion at the wiring connections, it can result in poor readings and faulty signals, causing the boiler to enter anti-cycling mode. To resolve this issue, it is important to check for loose wiring connections at the wire harness plugs and ensure they are secure and properly connected. If any corrosion is found, it is advisable to clean or replace the affected components as necessary.

Cause Solution
Corrosion at wiring connections Check for loose wiring connections, clean or replace affected components
Blocked drain switch Replace the switch if it is malfunctioning or obstructed
Fluctuating water temperature Ensure proper water inlet temperature and adjust as necessary
Ignition failure Inspect and troubleshoot the gas supply, flue blockages, and ignition lead issues

In addition to wiring issues, a blocked drain switch can also trigger anti-cycling in Lochinvar boilers. The drain switch is responsible for detecting and signaling when the boiler’s drainage system is blocked. If the switch is malfunctioning or obstructed, it can give a false indication of a blocked system, resulting in anti-cycling. In such cases, the switch should be replaced to restore proper functionality and prevent unwanted anti-cycling.

Furthermore, fluctuating water temperatures can also lead to anti-cycling. The control system in Lochinvar boilers utilizes the inlet water temperature as a reference point. If the inlet water temperature drops too much, the control system may activate anti-cycling to protect the boiler. It is important to ensure that the boiler’s inlet water temperature is within the recommended range to prevent unnecessary anti-cycling.

Lastly, ignition failure can also be a cause of anti-cycling. Gas valve blockages, flue obstructions, or faulty ignition leads can lead to ignition failure, triggering the anti-cycling mode. If a boiler lockout occurs due to ignition failure, it is recommended to consult a qualified technician to inspect and resolve the issue.

Resetting Lochinvar Knight Boiler

To reset the maintenance reminder on your Lochinvar Knight Boiler:

  1. Locate the maintenance reminder reset button on the control panel.
  2. Press and hold the reset button for 5 seconds until the maintenance reminder is cleared.
  3. Verify that the maintenance reminder has been successfully reset.

If your Lochinvar Knight Boiler displays a ‘Blocked’ or ‘High T’ status:

  • Check for loose wiring connections at the wire harness plug.
  • Inspect the blocked drain switch and replace it if necessary.
  • Address any corrosion at the wiring connections that may be causing a poor reading.

The ‘blocked’ status is not necessarily a fault but indicates the current status of the boiler. The anti-cycling feature on the boiler controls helps regulate its operation efficiently.

Troubleshooting Tips

If you are experiencing issues with your Lochinvar Boiler Blocked Anti Cycling, there are a few troubleshooting tips that you can follow to identify and resolve the problem. In this section, we will look at checking wiring connections, replacing the blocked drain switch, and dealing with low voltage.

Checking Wiring Connections

If your boiler is displaying the blocked anti-cycling message, it could be due to loose wiring connections. To troubleshoot this issue, start by checking the wiring connections at the wire harness plug. Ensure that all connections are secure and free from corrosion. If any loose connections are found, tighten them to ensure a proper electrical connection.

Replacing Blocked Drain Switch

A blocked drain switch could also be the culprit behind the anti-cycling issue. If the switch is faulty or blocked, it can trigger the blocked anti-cycling message on the boiler. To address this, you can replace the blocked drain switch with a new one to ensure proper operation and prevent the anti-cycling message from reappearing.

Dealing With Low Voltage

In some cases, low voltage can contribute to the blocked anti-cycling message on the Lochinvar boiler. To troubleshoot this, check the voltage supply to the boiler and ensure it meets the manufacturer’s specifications. If the voltage is below the recommended level, consult a qualified technician to address the low voltage issue and restore proper operation of the boiler.

Bypassing Anti-cycling Time

When it comes to the functioning of a Lochinvar boiler, the control system is an essential component responsible for regulating various parameters to ensure efficient operation. One crucial function of the control system is bypassing the anti-cycling time, especially when dealing with temperature drops. Understanding the mechanisms and techniques for bypassing the anti-cycling time is crucial for maintaining optimal performance and preventing potential issues with the boiler.

Control Bypassing For Temperature Drops

Control bypassing for temperature drops is a critical aspect of managing the anti-cycling function in Lochinvar boilers. When the inlet water temperature decreases significantly, the control system needs to bypass the anti-cycling time to prevent disruptions in the heating process. This bypassing ensures that the boiler can continue operating effectively, even during periods of temperature fluctuation.

Ensuring Optimal Functionality

Ensuring the optimal functionality of the control system in bypassing the anti-cycling time is essential for maintaining the performance of Lochinvar boilers. Regular inspections and maintenance of the control components, including sensors and actuators, can help identify any potential issues that may affect the bypassing process. Additionally, proper training for personnel responsible for managing the boiler system can contribute to efficient control bypassing and overall system maintenance.

By addressing the bypassing of anti-cycling time in Lochinvar boilers, it is possible to enhance the reliability and efficiency of these systems while minimizing the risk of temperature-related disruptions.

Frequently Asked Questions

What Is the Problem With the Lochinvar Boiler?

The Lochinvar boiler may emit carbon monoxide due to a cracked flue collector from high-impact events.

What Are The Symptoms Of A Blocked Heat Exchanger?

Symptoms of a blocked heat exchanger include inconsistent water temperature, reduced hot water supply, unusual noises, rapid pressure increase, and failure of radiators to heat up.

Why Does My Combi Boiler Keep Locking Out?

A combi boiler may keep locking out due to issues with the gas supply or ignition failure. Common causes include blockages in the flue, a faulty gas valve, or problems with the ignition lead. Resetting the boiler may not solve the issue, so it’s best to have a professional engineer inspect and diagnose the problem.

How Do I Reset My Lochinvar Knight Boiler?

To reset your Lochinvar Knight boiler, locate the “Reset” button on the unit’s display panel. Press the button to reset the boiler.

What Are the Potential Risks of a Blocked Lochinvar Boiler?

If the flue collector cracks, carbon monoxide can escape, posing a risk of poisoning.


A blocked anti-cycling mechanism in the Lochinvar boiler can cause issues such as inconsistent water temperature, reduced hot water supply, unusual noises, and the failure of radiators to heat up. It is important to address this problem, as it can lead to inefficiency and potentially hazardous situations.

If you are experiencing these symptoms, it is recommended that you consult a professional plumber or boiler technician to diagnose and resolve the issue. Taking prompt action will ensure the safe and reliable operation of your Lochinvar boiler.

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