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P/N  01661

Lead/Lag Controller

Model LL357D4

Operational Specifications

•  Thermostat Range: 45ºF to 90ºF (7ºC 

to 32ºC)

•  Accuracy: ±1ºF (± ½ºC)
•  Changeover Temperature Differential 

(separation between the heat set 
point and the cool set point): 2ºF to 
9ºF (1.0ºC to 4.5ºC)

•  First Stage Temperature Differential 

(number of degrees between the set 
point temperature and the “turn on” 
temperature): 1ºF to 3ºF (.5ºC to 
1.5ºC)

•  Second Stage Temperature Differential 

(number of degrees between when 
stage 1 turns on and when stage 2 
turns on): 1ºF to 6ºF (.5ºC to 3.0ºC).

•  Minimum Cool Temperature Set Point: 

Adjustable from 45ºF to 75ºF (7ºC to 
24.0ºC).

•  Maximum Heat Temperature Set 

Point: Adjustable from 55ºF to 90ºF 
(13ºC to 32.0ºC)

•  Staged OFF Outputs: Air conditioners 

will turn off independently.

Electrical Specifications
•  Compatible with standard 24-volt AC, 

2 stage heating/cooling systems.

•  24 Volt control (18 to 30 VAC).
•  1 amp maximum per terminal.
•  4 amp maximum total load.
Ease of Use
•  Back lighting of the large display 

makes the Liquid Crystal Display 
(LCD) easy to read.

•  Most frequently used keys are located 

by the LCD for quick & easy access to 
information.

•  Easy installation, setup and system 

tests saves time.

•  Setpoints are permanently held in 

memory and retained during power 
outages - no batteries required.

•  Programming not required.
•  Digital display shows temperature in 

°F or °C.

•  Room Temperature Offset: Used to 

calibrate displayed room temperature 
with actual room temperature

•  Status Indicator Light: Indicates which 

stage is running. Green light means 
cooling & red light means heating.

Model LL357D4 Lead/Lag Controller

The Marvair

®

 LL357D4 is a complete control package 

designed to operate a fully or partially redundant air 
conditioning system. It consists of a two-stage heat and 
cool electronic thermostat and a solid state timer. It 
can be used with either the Marvair ComPac

®

 I vertical 

packaged wall mount air conditioner, our unique ComPac

®

 

II air conditioner with built-in economizer and many of the 
Marvair Environmental Control Units (ECU). The LL357D4 
provides environmental control and the security demanded 
by the communication shelter industry for a back-up 
unit. The lead/lag controller insures equal wear on both 
air conditioners while allowing the lag unit to assist upon 
demand. Phasing of air conditioners is not required for 
proper operation. The environmentally safe, mercury-free LL357D4 is factory wired, 
tested and mounted in an enclosure for quick installation. The LL357D4 when used 
with the heat pump adapter, Model LL357H, provides control of redundant heat pump 
systems. Refer to the Heat Pump Adapter Product Bulletin for details.

Specification/Features

LL357D4 PDS 4.2011 rev. 1

Содержание Marvair LL357D4

Страница 1: ...ng power outages no batteries required Programming not required Digital display shows temperature in F or C Room Temperature Offset Used to calibrate displayed room temperature with actual room temper...

Страница 2: ...box for control wiring to air conditioners Low Voltage Wiring 1 All wiring must comply with local codes and ordinances 2 Disconnect power to prevent electrical shock or equipment damage 3 On dual uni...

Страница 3: ...lectrical codes and ordinances Note Mount the thermostat about five feet above the floor Do not mount the thermostat on an outside wall in direct sunlight behind a door or in an area affected by a ven...

Страница 4: ...stem The LL357D4 functions with air conditioners with electric heat systems To configure the LL357D4 perform the following steps 1 Verify that the LL357D4 is in the OFF mode Press the SYS left button...

Страница 5: ...t up for Non Heat Pump and Type of Heat Electric Press the Up or Down button to select scale Press the Right button to advance to the next screen Press the Up or Down button to select Press the Right...

Страница 6: ...set to 0 will display Press the Up or Down button to select Press the Right button to advance to the next screen 12 Temperature Sensor 1 3 1 Only on board sensor determines room temperature 2 Only re...

Страница 7: ...n the lead lag control should be on One amber light will be on to identify the lead unit The other light should be off If the lag unit comes on with the lead unit the light for the lag unit will not c...

Страница 8: ...ode In this mode the thermostat controls the heating system When the heat is on the flame icon appears on the display Cool Mode In this mode the thermostat controls the cooling system When the the uni...

Страница 9: ...de steps 2 3 Status indicator light does not come on during call for Cooling or Heating Turn status indicator light function on See Config Mode Step 14 Room temperature is not correct Calibrate thermo...

Страница 10: ...of compressors Select non heat pump and Electric 1 GAS 7 Auxiliary Delay On Set the time delay in minutes for aux heat to be locked out after a call for second stage Set to 0 minutes 1 0 00 8 Lockout...

Страница 11: ...LL357D4 PDS 4 2011 11 Notes...

Страница 12: ...e at www marvair com for the latest product literature Detailed dimensional data is available upon request A complete warranty statement can be found in each product s Installation Operation Manual on...

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