What must not be installed between the boiler and safety device/control?

When considering what should not be installed between a boiler and its safety device or control, unobstructive devices are critical for maintaining the integrity and functionality of the system. Safety devices and controls are designed to monitor and manage the operation of the boiler to prevent dangerous conditions such as overheating or pressure buildup.

If obstructive devices were installed, they could impede the proper operation of these safety mechanisms. This could lead to delays in response to unsafe conditions, potentially resulting in hazardous situations, equipment failure, or even catastrophic incidents. Therefore, maintaining clear and direct pathways between the boiler and its safety controls is essential for ensuring safety and reliability.

In contrast, while unapproved fittings, monitoring equipment, and regular valves may present issues in terms of compliance or efficiency, they do not inherently obstruct the function and direct communication between the boiler and safety devices as obstructive devices would. This highlights the importance of keeping the pathway clear for safety devices to operate effectively.