Figure #2, Figure #1 – Detcon FP-624C User Manual

Page 9

Ventilation - Normal ventilation or prevailing wind conditions can dictate efficient location of gas sensors in a

manner where the migration of gas clouds is quickly detected.

Personnel Exposure - The undetected migration of gas clouds should not be allowed to approach concentrated per-

sonnel areas such as control rooms, maintenance or warehouse buildings. A more general and applicable thought

toward selecting sensor location is combining leak source and perimeter protection in the best possible configuration.

Note: In all installations, the sensor element in SS housing points down relative to grade (Fig. 1). Improper sensor

orientation may result in false reading and permanent sensor damage.

3.5.3 Local Electrical Codes

Sensor and transmitter assemblies should be installed in accordance with all local electrical codes. Use appropriate

conduit seals. Drains are required at the bottom of vertical conduit runs. The sensor assemblies are designed to

meet NEC and CSA requirements for Class I; Div. 1; Groups B, C, D, environments.

3.5.4 Accessibility

Consideration should be given to easy access by maintenance personnel as well as the consequences of close prox-

imity to contaminants that may foul the sensor prematurely.

Note: An appropriate conduit seal must be located within 18" of the sensor assembly. Crouse Hinds type EYS2,

EYD2 or equivalent are suitable for this purpose.

3.5.5 Installation Procedure

Remove the junction box cover and un-plug the control circuit by grasping the two thumb screws and pulling outward.

Securely mount the sensor junction box in accordance with recommended practice. See dimensional drawing (Fig. 2).

Observing correct polarity, terminate 3 conductor field wiring, RS-485 wiring, and applicable alarm wiring to the

sensor base connector board in accordance with the detail shown in Figure 3. Normally open and normally closed

Form C dry contacts (rated 5 amp @ 120VAC; 5 amp @ 30VDC) are provided for Fault, Alarm 1, and Alarm 2.

Note 1 : The second electrical port should be used for wiring to relay contacts or to connect RS-485 and/or 24

volt power source to the next sensor in the serial loop (never mix VAC and VDC in the same conduit run).

Note 2: Per U.L. approval, these relays may only be used in connecting to devices that are powered by the same

voltages.

Model FP-624C Combustible Gas Sensor PG.9

4 3/4"

3/4" NPT

1/4" Dia.

Mounting Holes

7 1/4"

6 1/8"
5 1/2"

3/4" NPT

Rainshield/

Splashguard

2 1/8"

Figure #2

EYS

Seal

Fitting

Drain

“T”

Plug any unused ports.

Figure #1