Johnson Controls A350R Catalog Page

Code No. LIT-1922535

Issued November 18, 2008

A350R

Electronic Temperature Reset Control (with Relay)

Description

The A350R Reset Controller is designed to raise or lower the setpoint of supply water temperature based upon a proportionate drop or rise in temperature at the master (outdoor) sensor. The control output is a Single-Pole, Single-Throw (SPST) normally open relay with Light-Emitting Diode (LED) indication.

The adjustable differential enables the user to match the amount of control (maximum to minimum) required for a given application. An adjustable reset ratio adapts to a variety of weather zones and to the specific heat loss characteristics of most buildings.

As with all System 350 products, the A350R is housed in a NEMA 1, high-impact plastic enclosure. The modular design provides easy, plug-together connections for quick installation and future expandability.

Features

•modular design enables stage, display, and transformer modules to be purchased and installed as necessary

•adjustable master reset setpoint (M.R.S.) enables the user to select a master (outdoor) sensor temperature starting point for the supply reset ramp

•adjustable minimum and maximum supply temperature permits compliance with equipment manufacturer’s specifications

•selectable warm weather shutdown temperature saves energy by disabling equipment when the master sensor temperature rises to a point where heating is no longer required

•adjustable setback temperature saves energy by lowering the supply temperature setpoint at night or during unoccupied periods

Applications

The A350R Temperature Reset Controller can be used as a stand-alone device or in

conjunction with plug-together accessory A350R modules. The addition of the S350A or S350C

for on/off output, or an S350P for a proportional or proportional plus integral output allows this temperature system to control a variety of single or multiple stage Heating Ventilation Air Conditioning and Refrigeration (HVAC/R) applications. Typical applications include reset of single or multistage boilers.

Selection Charts

Code Number	Item	Description
A350RS-1C	A350R Temperature Reset Control	Temperature Reset Control
		(packaged with A99BB-300C and A99BC-25C sensors)

A350RT-1C	A350R Temperature Reset Control	Temperature Reset Control
		(temperature sensors not included)
Accessories and Replacement Parts
Code Number	Item	Description
D350AA-1C	Display Module	Fahrenheit Scale
D350BA-1C		Celsius Scale
S350AA-1C	On-Off Stage Module	Fahrenheit Scale
S350AB-1C		Celsius Scale
S350CC-1C	Slave Stage Module	Dual Scale (°F and °C)
S350PQ-1C	Proportional Stage Module	Dual Scale (°F and °C)
Y350R-1C	Power Module	120/240 VAC, 50/60 Hz input; rectified 24V Class 2 output
A99BB-300C	Temperature Sensors	PTC Silicon Sensor with PVC Cable; Cable length 9-3/4 ft (3m)
A99BC-25C		PTC Silcon Sensor with high temp. silicon cable; cable length 9-3/4 in. (0.25 m)
A99BC-300C		PTC Silcon Sensor with high temp. silicon cable; cable length 9-3/4 ft (3 m)
A99BC-500C		PTC Silcon Sensor with high temp. silicon cable; cable length 16-3/8 ft (5 m)
A99BC-1500C		PTC Silcon Sensor with high temp. silicon cable; cable length 49 ft (15 m)

BOX10A-600R	Enclosure	PVC Sensor Enclosure
WEL11A-601R	Immersion Well	For liquid sensing applications
SHL10A-603R	Sun Shield	For use with outside sensors in sunny locations
BKT287-1R	DIN Rail Sections	35 x 7.5 mm, 12 in./0.305 m long
BKT287-2R		35 x 7.5 mm, 36 in./0.914 m long
PLT344-1R	DIN Rail End Clamps	Two end clamps
WHA29A-600R	Cable for Remote Mounting	3 ft (0.9 m) 1
WHA29A-603R	of D350 Display Module	25 ft (7.6 m)
WHA29A-604R		50 ft (15.2 m)

1. WHA29A-600R can also be used to daisy chain S350 Stage Modules together.

The performance specifications are nominal and conform to acceptable industry standards. For applications at conditions beyond these specifications, consult the local Johnson Controls office. Johnson Controls, Inc. shall not be liable for damages resulting from misapplication or misuse of its products. © 2008 Johnson Controls, Inc. www.johnsoncontrols.com

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Electronic Temperature Reset Control (With Relay) (Continued)

Technical Specifications

A350R Electronic Temperature Reset Control

Supply Voltage 1

Transformer:

20 to 30 VAC, Class 2, 50/60 Hz

Y350R:

120/240 VAC, 50/60 Hz

Power Consumption

3.2 VA maximum

Ambient Temperature

Operating:

-30 to 150°F (-34 to 66°C)

Shipping:

-40 to 185°F (-40 to 85°C)

Humidity

0 to 95% RH non-condensing, 85°F (29°C) maximum dew point

Reset Ratio Adjustment Range

1:5 to 3:1 (master supply)

Reset Action

Reverse acting

Master Reset Setpoint Adjustment Range

40 to 70°F (4 to 21°C)

Minimum Supply Temperature Adjustment Range

50 to 160°F (10 to 71°C)

Maximum Supply Temperature Adjustment Range

160 to 220°F (71 to 104°C)

Differential Adjustment Range

1 to 30F° (0.5 to 17C°)

Relay On-Time

Jumper Selectable: OFF, 1 min., 2 min., or 3 min.

Warm Weather Shutdown

Jumper Selectable: OFF, 60, 64, 68, or 72°F (OFF, 16, 18, 20, or 22°C)

Setback Adjustment Range

0 to 30F° (0 to 17C°)

(Enabled by an external time clock)

Mode of Operation

Heating (Differential is below the setpoint.)

Relay Contact

SPST maximum: 4A non-inductive, 24 VAC; Pilot Duty 42.4 VA at 24 VAC

minimum: 100 mA at 5 VDC

Case and Cover Material

NEMA 1, high-impact thermoplastic

Agency Listing

UL Guide No. XAPX and cUL Guide No. XAPX7, File E27734

1. Only one supply voltage source may be used.

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A350R Dimensions, in. (mm)

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