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Honeywell L6006A Aquastat controller Resideo Honeywell L6006A Aquastat Information
Buy, replace, install, set-up, & wire the L6006A aquastat control

Guide to aquastat controls on heating equipment:

This article series explains how aquastats work and what the different aquastat controls are, what they do, and how they are set. We define the HI LO and DIFF controls on heating boiler aquastats and explains what they do and how they work. We explain the location and use of the heating boiler reset button found on aquastats.

We discuss relationship among HI, LO, DIFF, and heating burner cut-in, cut-out, and circulator lockout that are provided on the combination control. We explain how the Aquastat controls hot water production via a tankless coil on the heating boiler.

We explain how to disable the LO control when a tankless coil is not in use on a boiler. After explaining the operation of an aquastat's Hi, Lo, and Diff controls we review the newer universal replacement aquastat from Honeywell, the L7224U Universal Aquastat, followed by a discussion of the simpler single-limit control switches.

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Honeywell / Resideo L6006A Aquastat Settings & Controls

Honeywell L6006A Aquastat controllerThe L6006 series aquastats are used for temperture control on boilers, hot water storage tanks, and similar equipment. These controls operate by placing a temperature sensor either directly into the water inside of a vessel or into an immersion well in the boiler or water heater.

Excerpting from the L6006 Aquastat Controller literature,

Aquastat® Controllers are immersion type devices for limiting or regulating the temperature of liquids in boilers, storage tanks, and other applications where temperature control is required. 

Strap-on models of this temperature control are available and are discussed separately

at STRAP-ON LIMIT CONTROL

 

Installing, Wiring, & Adjusting the L6006A Aquastat Controller

Honeywell Resideo L6006A fatory-set stop adjustment procedure - cited & discussed at InspectApedia.com

Above: illustrating how we use a paper clip to change the factory-set stop limit on the L6006A Aquastat.

Excerpts from Resideo L6006A AQUASTAT CONTROLLER INSTALLATION INSTRUCTIONS [PDF] (2020) Resideo Controls (nee Honeywell) illustrated above.

Wiring The L6006A Aquastat Controller

Disconnect power supply before connecting wiring to prevent electrical shock or equipment damage. Make sure all wiring complies with local electrical codes and ordinances. The case has a knockout for 1/2 in. conduit

Wiring diagram for the L6006 Aquastat when it is providing a low limit control and circulator control on an oil boiler - cited & discussed at InspectApedia.com

Above: wiring diagram for the L6006 Aquastat when it is providing a low limit control and circulator control on an oil boiler hot water (hydronic) heating system.

[Click to enlarge any image]

Below: wiring diagram for the L6006 Aquastat when used with the L8148 Aquastat relay.

wiring diagram for the L6006 Aquastat when used with the L8148 Aquastat relay. - cited & discussed at InspectApedia.com

 



OPERATION of the L6006A Aquastat Controller

Select control settings according to the heating system manufacturer recommendations.

High-limit Controller shuts off burner when water temperature exceeds high-limit setting.

R-B contacts make, and burner restarts when temperature drops to high-limit setting minus the temperature differential.

Low-limit Controllerómaintains minimum water temperature for domestic hot water; e.g., tankless coil in heating boiler.

Makes R-B contacts at temperature setting minus differential.

Circulator Controller prevents circulation of water that is not hot enough.

Breaks R-W contacts for circulator circuit at temperature setting minus differential; remakes the R-W contacts for circuit when the temperature setting is reached.

Switching action operates as follows:

When there is a drop in water temperature (to dial setting, less differential), the R to B contacts make and the R to W contacts break, preventing circulator operation.

When there is a rise in water temperature (to dial setting), R to B contacts break and R to W circulator contacts make.

ADJUSTMENT of the Resideo (Honeywell) L6006 Control Differential

Set the differential according to the system manufacturer recommendations.

Rotate the wheel on the back of the snap switch until the desired reading is aligned with the V notch in the frame.

The wheel provides an adjustment from 5°F to 30°F (3°C to 17°C).

Replace the cover on the Aquastat Controller.

Adjust the control point according to the system manufacturer recommendations.

To adjust, insert a screwdriver in the slotted screw type head located beneath the window in the cover.

Turn the scale to the desired control point. Move the factory-set stop if desired, as shown in Fig. 5.

CHECKOUT Procedure for the L6006A Aquastat Control

Check to make certain that the Aquastat Controller was installed and adjusted properly.

Put the system into operation and observe the action of the device through several cycles to make certain that it provides proper limit and circulator control

Reader Question: how to set the large and small dials on the Honeywell L6006A

(Dec 23, 2014) Mark said:
I was looking for a bit more explanation (or perhaps just a layman's explanation) of an aquastat's hi/low/diff functions as it relates to my specific situation.

[Click to enlarge any image]

My aquastat is the Honeywell L6006A. It has one large dial and one smaller (differential) dial. It is attached downstream from a heat exchanger/air handler unit in my gas-fired hydronic heating system, and the fan is being controlled by the aquastat.

I have the large dial at 160and the differential to 5 degrees.

Does this mean that when the water in the heat exchanger reaches approx 165 the fan should turn-on, and when it cools to approx 155 it should turn-off?

Reply:

Thanks Mark:

The large dial whose numbers you see when the control cover is on is the HI or HIGH LIMIT - see SETPOINT INDICATING WHEELin Honeywell's illustration adapted at above left

There is a smaller DIFFerential setting dial inside the control - in the illustration at above left see DIFFERENTIAL ADJUSTMENT WHEEL.

The aquastat is monitoring water temperature at the point where its sensor is installed in order to turn the burner on and off.

Click and enlarge the white, green, yellow illustration in the article just above to see how a typical Honeywell control relates the DIFF setting to heat on or off.

Here is what the manufacturer says:

Key is this phrase about the High Limit found below:

Turns on burner at temperature setting, minus differential.

For proper selection of settings, follow the boiler manufacturer recommendations.

Watch out: although it may be marked as "optionl" in some company illustrations, the company also provides and recommends use of a heat-conducting grease when installing the L606A high limit controller into its immersion well on the heating appliance.

Without good thermal contact between the temperature sensing bulb [ INSERTION ELEMENT in the illustration above and shown in detail just below] the control may not operate reliably.

Aquastat immersion well sensor details, adapted from Honeywell's L7224U universal aquastat installation instructions cited in this article series (C) InspectApedia 2015

[Click to enlarge any image]

Honeywell L6006A High limit controller

— Shuts off burner when water temperature exceeds high limit setting. Burner restarts when temperature drops to high limit setting, less differential.

Honeywell L6006A Low limit controller

— Maintains minimum boiler temperature for domestic hot water. Turns on burner at temperature setting, minus differential.

Honeywell L6006A Circulator controller

— Prevents circulation of water that is not hot enough. Breaks circulator circuit at temperature setting minus differential; remakes the circuit when the temperature setting is reached.

Honeywell L6006A Switching action is as follows:

Upon a drop in boiler water temperature (to dial setting, less differential), makes R to B burner contact; breaks R to W contact, preventing circulator operation.

Upon a rise in boiler water temperature (to dial setting), breaks R to B burner contact, makes R to W circulator contact

Honeywell L4006, L6006, L4008 & L6008 Aquastats: Installation, Wiring & Operation Manuals

We provide links just below to several other aquastat installation, setting, and adjustment documents in response to reader requests and comments that people sometimes have difficulty finding this information. But readers looking for specific aquastat control information should always first try the control manufacturer to see if there are newer instructions.

 


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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-06-05 - by (mod) - where do the wires go on the L6006A?

Honeywell L6006A Aquastat limit control interior wiring terminals (C) InspectApedia.com

[Click to enlarge any image]

Richard,

Thank you for the photo and question about wiring the Honeywell L6006A Aquastat / limit control.

The short answer is that the white neutral wire goes to terminal "W" in the L6006A in your photo.

Details are below and in my annotated version of your photo.

Take a closer look at the letters printed by the three screws below the dial inside your unit and you will see that from the topmost terminal down the screws are marked as follows:

R = "Red" = in the L6006A is connected to the L1 terminal if the L6006A is being connected to an L8148A Aquastat (Fig. 4 that I will attach)
or it is connected to the Switching relay (Fig. 3 that I will attach)

B = Black = in the L6006A is connected to the "B" terminal if connecting to an L8148A Aquastat relay (Fig. 4)
or it is connected to L1 or "Hot" line voltage (Fig. 3)

W = White = "Neutral" - connects to terminal 3 if connecting to an L8148A Aquastat relay (Fig 4).

or it is connected directly to L2 or "Line 2" which is the power circuit neutral wire (Fig. 3)

If you don't have the installation Honewell L6006A INSTALLATION & WIRING INSTRUCTIONS [PDF] you can download a copy here - live link above on this page.

I'll post two excerpt wiring diagrams below.

Watch out: if you are not familiar with safe electrical wiring, know that you can be shocked or killed.

L6006A wiring diagram at InspectApedia.com

and [Click to enlarge any image]

Honeywell L6006A wiring diagram Figure 4 at inspectApedia.com

On 2020-06-05 - by (mod) -

Give me a couple of minutes Richard

On 2020-06-05 by Richard - On the L6006A controller, where does the white neutral supplies go?

On the L6006A controller, where does the white neutral supplies go?

Honeywell L6006A Aquastat limit control interior wiring terminals (C) InspectApedia.com Richard

On 2020-02-08 - by (mod) -

This link

https://inspectapedia.com/heat/Honeywell_L6006A_Aquastat.pdf

to installation instructions was given the nearer to call above and will give you the detailed wiring connections. Please take a look and don't hesitate to ask me any follow-up questions.

On 2020-02-08 by hayward cull - how do you hook the L6006A up- what wires goes onwhat screw

how do you hook it up what wires goes onwhat screw

On 2020-01-02 by dw

i need an aquastat that has contacts that close on high temp

On 2019-10-14 - by (mod) -

Matt

Let's check the settings discussed

at AQUASTAT HI LO DIFF SETTINGS

to be sure you haven't interlocked the control by setting the LO too close to the HI

On 2019-10-13 by Matt

I have my aquastat set at 150 and it shuts off before 150 and don't turn on until it gets to 100. My dif is set at 10. What could the problem be?

On 2019-01-22 - by (mod) -

Al

I would not expect a new aquastat to make water hot again - we need a more-thorough diagnosis of the problem.

For example, scale clogging can reduce hot water quantity and temperature;

A poorly-mounted aquastat temperature sensor or one lacking the heat conductive grease in a sensor well could cause the aquastat to fail to sense water temperature properly.

Let's get a service tech on site.

On 2019-01-21 by Al

Water getting warm not hot like before will new aquastats make water hot again

On 2016-11-20 by bill

Wood fired boiler with 6006a aquastat. Only running a selonoid to open and close a dampener
How do we wire. It to do ,this


...

Continue reading at AQUASTAT HI LO DIFF SETTINGS that explains the best settings to use & how & when to disable the LOW & DIFF controls or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

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Suggested citation for this web page

AQUASTAT L6006A HONEYWELL GUIDE at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING BOILERS

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