AbsolutAire A19 Installation Manual

Installation Sheets Manual 121 Temperature Controls Section A Technical Bulletin A19 Issue Date 0588

A19 Series Temperature Controls -- Single-Pole,

Single-Throw and Single-Pole, Double-Throw

Models with NEMA 1 Enclosure

Application

These controls are designed to cover a broad range of general purpose operating temperature control applications in the refrigeration, air conditioning and heating field with a minimum number of models. Typical applications are: frozen food cases, display cases, beverage coolers, milk coolers, etc. Various control ranges are available.

Controls are supplied with an adjustable range (except models with factory sealed settings) and adjustable or nonadjustable differential.

All Series A19 temperature controls are designed for use

only

as operating controls. Where an operating control failure would result in personal injury and/or loss of property, it is the responsibility of the installer to add devices (safety, limit controls) or systems (alarm, supervisory systems) that protect against, or warn of, control failure.

Installation

Follow equipment manufacturer’s instructions if provided. If instructions are not provided proceed as follows:

Mounting

Controls are normally mounted to a surface through holes in back of case.

CAUTION: On rough

mounting surfaces use the top two mounting holes only. When these controls are mounted on an uneven surface using screws in all four holes, the case can be twisted enough to affect the control’s calibration and operation.

For closed tank applications without well assembly Part No. FTG13A600R packing nut assembly may be supplied. See Fig. 2 for sequence of installation. Put parts over support tube section of element, placing bulb into tank. Tighten 1/2 in. NPT adapter. Screw packing nut into adapter with the retaining washers and packing in place as shown.

To install models supplied with bulb well, first install bulb well into tank. Remove bushing from bulb well and slide bushing over capillary. Replace bushing into bulb well. Push bulb into position in bottom of well. Tighten set screw in end of adapter to hold bulb in position. See Fig. 3 for bulb well illustration.

CAUTION: Do not dent or

deform the sensitive bulb of this control. A dent or deformation will change the calibration and cause the control to cycle at a temperature lower than the dial setting. When the bulb mounting clip is used to mount the bulb near the refrigerant tubing, be sure the sheet metal screw does not pierce the tubing.

Fig. 1 -- An A19 with external range

adjustment and screwdriver slot.

Adjustments

The A19 temperature controls may be supplied with an external range adjustment and screwdriver slot as shown in Fig. 1, range adjustment knob or solid cover. Solid cover models with calibrated dial are adjusted by removing the cover and moving dial so the desired setting is in line with the dial pointer on the stop bracket. (See Fig. 5.) Convertible adjustment models can be field converted from concealed screwdriver slot adjustment to knob adjustment or external screwdriver slot adjustment. They are supplied with a snap-in plug in the cover to provide concealed screwdriver slot adjustment. For knob adjustment remove the snap-in plug and press the knob onto the slotted shaft. For external screwdriver slot adjustment remove the snap-in plug. The convertible adjustment models with remote bulb include a bulb mounting clip.

Part No. 997-349

Low cutout or high cutout stop supplied on certain models (specified by the equipment manufacturer).

CAUTION: Use terminal

screws furnished (8-32 × 1/4 in. binder head). Substitution of other screws may cause problems in making proper connections.

Fig. 2 -- Part No. FTG13A-600R

packing nut assembly. (Used with

Checkout Procedure

swaged bulb with support tube for

direct immersion application.)

Before applying power, make sure installation and wiring connections are according to job specifications.

Fig. 4 -- Terminal arrangement of

SPDT models.

After the necessary mechanical adjustment and electrical connections have been made, an operational checkout is recommended.

Fig. 3 -- Bulb well for liquid

immersion applications where a

temperature bulb may be removed

without draining tank.

If high or low cutout stop adjustment is required proceed as follows:

1. Set dial to temperature at which stop is desired.

2. Remove cover of the control.

3. Loosen the cutout stop screw, slide the screw to the front of the temperature control against

Adjust the control setpoint to put the system in operation and observe at least three complete operating cycles to be sure that all components are functioning correctly.

If the system fails to operate, recheck the wiring and components.

the plastic step behind the dial

Dial settings normally indicate the cutout setting unless otherwise specified by the equipment manufacturer. Models with SPDT contacts are normally set so the red (common) to yellow contacts open at the dial setting.

and tighten the screw. (See Fig. 5.) Sometimes an exact stop setting is not possible and stop must be set to the closest stop corresponding to dial setting required.

4. Replace cover.

Repairs and Replacement

Field repairs must not be made. For a replacement control contact the nearest Johnson Controls representative.

Models with adjustable differential and ranges of 20/80°F (-5/28°C),

Wiring

-30/50°F (-35/10°C) and -30/100°F (-35/40°C) have a differential scale plate showing increments of differential. Other ranges have a scale plate with a multiplier. For example when “MIN” differential is 5F° (2.8C°) then x2 is 10F° (5.6C°), x3 is 15F° (8.3C°), etc. The controls are supplied with adjusting lever at minimum differential stamped on the control. To adjust move the lever to the differential required.

CAUTION: Disconnect

power supply before wiring connections are made to avoid possible electrical shock or damage to equipment.

All wiring should conform to the National Electrical Code and local codes. Single-pole, double-throw models should be wired as shown in Fig. 4. Use copper conductor only.

Fig. 5 -- All models have a screw

type cutout stop. The stop screw

must be loosened and moved to

the stop setting desired. Tighten

screw after setting is made.

Controls Group

507 E. Michigan Street P.O. Box 423 Printed in U.S.A. Milwaukee, WI 53202

A19 Technical Bulletin

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