The L404F1078 is a Honeywell High-Limit or Low-Limit Aquastat Controller, commonly used in hydronic heating systems, boilers, and other temperature control applications to provide temperature regulation and safety cut-off.

English Description

The Honeywell L404F1078 is a mechanical Aquastat controller designed for surface mounting on pipes or in immersion wells. Its primary function is to sense the water temperature in a boiler or hydronic system and actuate a switch (open or close contacts) when the temperature reaches a set high or low limit. It's often used as a safety device to prevent overheating (high-limit) or to maintain a minimum temperature (low-limit/circulator control).

Key features and characteristics of the L404F1078 include:

• Manufacturer: Honeywell.

• Type: Aquastat Controller (High-Limit or Low-Limit).

• Temperature Range: Typically features an adjustable temperature range, common for L404F models is 100°F to 240°F (38°C to 116°C).

• Differential: Includes an adjustable or fixed differential, which is the temperature difference between the setpoint and the actual temperature at which the contacts reset. For L404F, it's often adjustable from 5°F to 30°F (3°C to 17°C).

• Sensing Element: Utilizes a liquid-filled sensing element (bulb) and capillary tube, which expands and contracts with temperature changes, mechanically operating the switch.

• Switch Action: Features a SPST (Single-Pole, Single-Throw) switch, meaning it has one set of contacts that either open or close to control the circuit. The "F" in L404F often indicates a specific switch action or a non-immersion type.

• Mounting: Designed for surface mounting with a strap onto pipes, or it can be used with a separate immersion well.

• Electrical Ratings: Specific models have different electrical ratings for various voltages and currents.

• Application:

• High-Limit Control: Prevents boiler or system water from exceeding a safe temperature, often as a safety shutdown.

• Low-Limit Control: Maintains a minimum boiler water temperature for domestic hot water priority or to prevent condensation.

• Circulator Control: Activates or deactivates a circulator pump based on water temperature.

• Used in residential and light commercial hydronic heating systems, boilers, and hot water storage tanks.

The L404F1078 is a fundamental and reliable component in hydronic systems, crucial for both temperature regulation and critical safety functions.

中文描述

L404F1078 是一款 霍尼韦尔 (Honeywell) 高限或低限水温控制器（Aquastat Controller），常用于水暖供热系统、锅炉及其他温度控制应用中，提供温度调节和安全切断功能。

主要特点和功能

霍尼韦尔 L404F1078 是一款机械式水温控制器（Aquastat controller），设计用于管道表面安装或浸入式套管安装。其主要功能是感应锅炉或水暖系统中的水温，并在温度达到设定的高限或低限时触发开关（打开或闭合触点）。它常被用作安全装置，以防止过热（高限）或保持最低温度（低限/循环泵控制）。

L404F1078 的主要特点和功能包括：

• 制造商： 霍尼韦尔 (Honeywell)。

• 类型： 水温控制器（高限或低限）。

• 温度范围： 通常具有可调节的温度范围，L404F 型号常见范围是 100°F 至 240°F（38°C 至 116°C）。

• 压差： 包含可调节或固定的压差，即设定点与触点复位时的实际温度之间的温差。对于 L404F，通常可在 **5°F 至 30°F（3°C 至 17°C）**之间调节。

• 感应元件： 采用充液感温包和毛细管，通过温度变化引起膨胀和收缩，机械操作开关。

• 开关动作： 具有 **SPST（单刀单掷）**开关，这意味着它有一组触点，通过打开或闭合来控制电路。“F”在 L404F 中通常表示特定的开关动作或非浸入式类型。

• 安装： 设计用于通过带子表面安装到管道上，或与单独的浸入式套管配合使用。

• 电气额定值： 具体型号具有针对不同电压和电流的不同电气额定值。

• 应用：

• 高限控制： 防止锅炉或系统水温超过安全温度，常作为安全停机装置。

• 低限控制： 维持锅炉最低水温，用于生活热水优先或防止冷凝。

• 循环泵控制： 根据水温激活或停用循环泵。

• 用于住宅和轻型商业水暖供热系统、锅炉和热水储存罐。

L404F1078 是水暖系统中一个基本且可靠的组件，对于温度调节和关键安全功能都至关重要。