Accustat Thermostats

The Accustat Temperature Control System

One of the most dependable ways of controlling the temperature is to use a non-adjustable sensor on your controls. Accustat controls feature a factory preset mercury thermometer that does the sensing.

The major advantages are:

  • Factory set
  • Nonadjustable
  • Operates in any position
  • No temperature drift
  • Precalibrated
  • High accuracy
  • Fast response
  • Unaffected by vibration
S-35 S-55 S-68 S-78
S-37 S-60 S-70 S-80
S-39 S-62 S-72 S-82
S-40 S-64 S-74 S-84
S-45 S-65 S-75 S-86
S-50 S-66 S-76 S-88

The wiring enclosure/bases feature an exclusive locking system as standard. Limiter models don’t have any external thermometers or switches to encourage meddling.

The wide variety of models include:

• Single setpoint
• Programmable
• Adjustable
• Digital line volt
• High/Low setpoint
• PTAC controls
• Adjustable with limiter
• Low volt
• Multistage
• Heat pump stats
• Duct limiters
• Millivolt
• Microamp
• Outdoor sensors

The Accustat Sensor
How it Works: Accutherm sensors use a mercury thermometer to sense the ambient temperature. As the temperature rises, the mercury expands and completes a circuit between the two rings on the thermometer. These rings are connected with the mercury column by a platinum wire embedded in the glass tube. These sensors snap into pre-wired holding clips mounted on the thermostat base. The factory preset sensors are completely nonadjustable and can be mounted almost anywhere. They are extremely durable and not normally sensitive to vibration.

Part # Accustat Sensor  
AS-90 Accustat Adjustable Sensor, Range -40 to 90 F Call... Add to Order

Digital Line Voltage Energy Control

This new microprocessor based control is designed to provide economic control for zoned baseboard and radiant heating systems. Utilizing a thermistor type sensor, as opposed to a traditional bimetal, this design lends far more precise control over the life of the system. Energy savings can come in as high as 30% by using this control. Batteries are not required. User set points are maintained through power outages of up to 10 seconds. Default set points are factory set at 55˚F for the economy mode and 68˚F for the comfort mode. Single and double pole models are available. Double pole models incorporate a power on/off switch; single pole models do not.


  • Digital set point display
  • 3 button easy operation
  • Temperature range of 40˚ to 90˚F
  • UL Approved
  • Designed in conjunction with the Electrical Power Research Institute
  • Patented Intella-Sens system ensures stable and precise temperature control, eliminating temperature swings, while preventing rapid cycling.
  • Load rating 22 amps maximum
  • Meets Power Smart‚ guidelines for energy efficiency
  • No batteries required
Part # Power Relay Default Set Point  
LV-120HS/68NL 120 VAC Single Pole 68 degrees F Call... Add to Order
LV-230HS/55NL 208/240 VAC Single Pole 55 degrees F Call... Add to Order
LV-240HD/55NL 240 VAC Double Pole 55 degrees F Call... Add to Order

E-Accustat with Electronic Sensing

The newly designed E-Accustat‚ contains all of the features of the original with the addition of an adjustable electronic temperature sensor. Just turn the stepper to the desired selectable temperature setting, replace the cover and you’re there…dependable and secure temperature control. The cycle rate can also be set over a range of 3 cycles per hour up to 6 cycles per hour. Remote sensing of up to 3 sensors with averaging can be achieved with this series. A setback model is available to provide economy settings, using a remote timer, light sensing device, computer or any device that can activate a 24VAC signal.


  • Rugged case design
  • Locking Mechanism
  • Solid State Switching
  • Electronic Sensing
  • Averaging of up to 3 sensors
  • Adjustable cycle rate
  • Single or Multiple Stages
  • Dual Set Points
  • Adjustable economy offset (setback)


  • Power: 24V
  • Temp. Range: 65˚ to 80˚ F
  • Rating: 1.2 amps per stage
  • ΔT: 2˚ between stages
LEMS2-AH11 2-Cool/2-Heat On/Off HT Auto/CL Auto/On
LEMS2-AH22 2-Cool/2-Heat
LEHP2-AH12 1-Cool/2-Heat EmHt/Heat/Auto/Cool Auto/On No
LEMS-AHSSAS-HD 2-Cool/2-Heat On/Off HT Auto/CL Auto/On

Part # E-Accustat & Accessories  
LEMS2-AH11 E-Accustat with Electronic Sensing Call... Add to Order
LEMS2-AH22 E-Accustat with Electronic Sensing Call... Add to Order
SRT-3 Remote Sensor for E-Accustat Call... Add to Order

Energy Guard Limiter Thermostats

Whether heating or cooling, these thermostats can hold the line on temperature abuse.

Energy Guard thermostats do more than just control room temperature. Special sensor(s) concealed inside limit maximum heating and/or minimum cooling room temperatures regardless of where the thermostat is set.Savings can be astronomical—in some cases as much as 50% or more.

Adjustable Thermostat with Built-in Limiter

This wall thermostat features an adjustable (AS-90) sensor and a snap-in limiter clip for a non-adjustable sensor for limiting the setpoint of either heating, cooling or heat/cool stats.


The limiter sensor overrides at the selected setpoint regardless of where the adjustable sensor is set. This gives thermostats fiddlers a dial to set wherever they want while the actual control is prevented from exceeding your selected limit.


  • Both adjustable and limited
  • No leveling
  • No thermometer on the cover
  • Standard terminal markings
  • No calibrating
  • No anticipator adjustments
Part # Settings Switches  
T30H-L 1-heat None Call... Add to Order
T32AH-L 1-heat / 1-cool Heat-Off-Cool / Fan-Auto-On Call... Add to Order

Accustat Thermostat Bases

Accustat wiring bases have pre-wired solid state relays connected to the thermostat mounting clips. These relays perform the desired Heat/Cool switching functions in either 24, 120 or 240Vac circuits, depending on the model you select.

NOTE: The multiple sensor models shown above (LH-2, LA-2, LAH-22) are not multistage. The second sensor is accessible through the high/low switch only and is not automatic. Use for selecting day/night, occupied/unoccupied or any other two-temperature control mode you need. For multistage models, see the LMS order chart below.

Part # Settings System Fan  
LA-1 1 Cool Off-On Auto-On Call... Add to Order
LA-2 Hi-Low Cool Low-Off-High Auto-On Call... Add to Order
LAH-11 1 Heat-1 Cool Heat-Off-Cool Auto-On (heat only) Call... Add to Order
LAH-11E 1 Heat-1 Cool Heat-Off-Cool Auto-On Call... Add to Order
LAH-22 High-Low Cool, High-Low Heat  Heat-Off-Cool, Low-High Auto-On (heat only) Call... Add to Order
LAH-22E High-Low Cool, High-Low Heat  Heat-Off-Cool, Low-High Auto-On Call... Add to Order
LH-1 1 Heat Off-On - Call... Add to Order
LH-2 Hi-Low Heat Low-Off-Hi - Call... Add to Order

Accustat Multistage Thermostats

Accustat multistage thermostats feature independent sensor/circuits for each stage. Each stage can be individually “fine-tuned” for maximum performance.

Since no anticipator devices are used, a major cause of multistage control inefficiency is eliminated. In the auto changeover mode, the dead band temperature zone is precise and drift free. A minimum dead band of 4° between the first stage heating and cooling is recommended, and 2° minimum between first and second stages where applicable. These thermostats use standard single stage preset sensors. Adjustable sensors are not recommended. order sensor separately.

Part # Stages Switches  
LMS-A2 2 Cool Off-On Call... Add to Order
LMS-AH11 1 Heat-1 Cool Heat-Auto-Cool, On-Off Call... Add to Order
LMS-AH22 2 Heat-2 Cool Heat-Off-Auto-Cool Call... Add to Order
LMS-AH22NS 2 Heat-2 Cool Heat-Auto-Cool, On-Off Call... Add to Order
LMS-H2 2 Heat Off-On Call... Add to Order