The Honeywell L6006A Aquastat Controller is an immersion-type device used for temperature regulation in boilers, hot water storage tanks, and similar applications. It functions by monitoring liquid temperature via a sensor placed directly into the water or an immersion well. The controller is designed to limit or regulate temperature, offering high-limit, low-limit, and circulator control functions. Proper installation, adjustment, and checkout procedures are critical for safe and effective operation. This article details the installation, operation, and adjustment of the L6006A Aquastat Controller, based on available documentation.
Understanding the L6006A Aquastat Controller
The L6006A Aquastat Controller is part of a series of similar devices used for temperature control. Immersion well models, designated L4006A, B, and E, require a snugly fitting well for optimal thermal response. The sensing bulb should rest against the bottom of the well, and the tubing may need bending to ensure secure contact. Accessories, such as well adapters, are available and detailed in form 68-0040, “Wells and Fittings for Temperature Controllers.”
The controller operates based on temperature readings and makes or breaks electrical contacts to control burners and circulators. It is crucial that installation is performed by a trained and experienced service technician. The device is designed to be used with systems adhering to local electrical codes and ordinances.
Installation Procedures
Prior to installation, disconnecting the power supply is paramount to prevent electrical shock or equipment damage. The installation process varies depending on whether the L6006A is used independently or in conjunction with an L8148 Aquastat relay.
Wiring diagrams are provided for both configurations. When used with the L8148 relay, the following connections apply:
- B (Black) connects to the "B" terminal.
- W (White) connects to terminal 3.
- R (Red) connects to the L1 terminal.
When wired directly, the connections are as follows:
- B (Black) connects to L1 or "Hot" line voltage.
- W (White) connects to L2 or the power circuit neutral wire.
- R (Red) connects to L1.
The case of the L6006A includes a knockout for 1/2 inch conduit to facilitate wiring.
Operational Characteristics
The L6006A Aquastat Controller provides three primary control functions: high-limit, low-limit, and circulator control.
High-Limit Control: The controller shuts off the burner when the water temperature exceeds the high-limit setting. When the temperature drops to the high-limit setting minus the temperature differential, the R-B contacts make, and the burner restarts.
Low-Limit Control: This function maintains a minimum water temperature, often used for domestic hot water systems, such as a tankless coil in a heating boiler. The R-B contacts make at the temperature setting minus the differential.
Circulator Control: The circulator controller prevents water circulation when the temperature is insufficient. It breaks the R-W contacts for the circulator circuit at the temperature setting minus the differential and remakes them when the temperature reaches the setpoint.
Specifically, a drop in boiler water temperature (to the dial setting, less the differential) causes the R to B burner contact to make, while the R to W contact breaks, preventing circulator operation. Conversely, a rise in boiler water temperature (to the dial setting) breaks the R to B burner contact and makes the R to W circulator contact.
Adjustment Procedures
The L6006A Aquastat Controller features two adjustment mechanisms: a control point adjustment and a differential adjustment. Both should be set according to the heating system manufacturer’s recommendations.
Control Point Adjustment: To adjust the control point, a screwdriver is inserted into the slotted screw head beneath the window in the cover. Turning the scale adjusts the desired control point. The factory-set stop can be moved if necessary.
Differential Adjustment: The differential is adjusted using a wheel on the back of the snap switch. Rotating the wheel aligns the desired reading with the V notch in the frame. The adjustment range is from 5°F to 30°F (3°C to 17°C). After adjustment, the cover should be replaced.
Checkout Procedure
After installation and adjustment, a checkout procedure is essential to verify proper operation. The system should be put into operation, and the Aquastat Controller’s action should be observed through several cycles to ensure it provides proper limit and circulator control.
Wiring Considerations and Safety
The documentation emphasizes the importance of safe electrical wiring practices. If unfamiliar with these practices, it is strongly advised to avoid self-installation due to the risk of electric shock or equipment damage. The white neutral wire connects to terminal "W" on the controller. The documentation provides detailed wiring diagrams for both configurations: with and without an L8148 Aquastat relay.
Specific Wiring Terminal Definitions
The terminals on the L6006A are clearly marked:
- R: Red – Connected to L1 or the switching relay.
- B: Black – Connected to the "B" terminal (with L8148) or L1 (direct wiring).
- W: White – Connected to terminal 3 (with L8148) or L2 (direct wiring).
Addressing Common Questions
A frequently asked question concerns the location of the white neutral wire. The documentation confirms that the white neutral wire connects to terminal "W" on the L6006A controller. Another inquiry related to an aquastat with contacts that close on high temperature; the L6006A operates by making or breaking contacts based on temperature thresholds and differential settings.
Immersion Well Installation
When installing immersion well models (L4006A, B, E), it is important to use a well that snugly fits the sensing bulb. The bulb should be positioned against the bottom of the well, and the tubing may need to be bent to maintain this contact. Refer to form 68-0040 for information on wells and fittings.
Conclusion
The Honeywell L6006A Aquastat Controller is a critical component in hydronic heating systems, providing precise temperature regulation and safety features. Proper installation, adjustment, and checkout procedures, as outlined in the manufacturer’s instructions, are essential for reliable and safe operation. Understanding the controller’s operational characteristics and wiring requirements is crucial for service technicians and experienced DIY users. Adherence to electrical safety guidelines is paramount throughout the installation process.