RKI Instruments 61-0190RK - Manual (Page 6)

2 • 61-1003RK/61-0190RK Combustible Gas Detector
Description
The 61-1003RK combustible gas detector has two versions, the 61-1003RK-CH4 which is
calibrated to methane and the 61-1003RK-HC which is calibrated to propane. The detector
is an infrared type of detector which has some advantages over a catalytic type of
combustible detector. The infrared detector will generally have a longer service life than a
catalytic detector, it will require calibration less often, and it can detect combustible gas
even if there is no oxygen in the sample which allows detection of combustible gas in an
inert atmosphere.
This section describes the components of the 61-1003RK. They include the infrared LEL
detector and the junction box.
Infrared LEL Detector
The infrared LEL detector is made up of a miniature infrared combustible gas LEL
detector housed and encapsulated in a pipe nipple. The pipe nipple has 3/4 inch NPT
threads on each end and a 1-1/4 inch hex that allows removal or installation of the
detector with a wrench. A porous flame arrestor coated with a hydrophobic film that
repels liquids is on one end of the detector and allows sample gas to enter the detector.
Four color coded leads, red, white, green, and black, extend from the other end of the
detector. The leads allow you to connect the detector to the terminal block in the junction
box.
To distinguish the propane detector from the methane detector (in case the replacement
detector label that is applied to one of the leads is lost), a short length of red shrink tubing
is applied to the white wire of the propane detector near where the wire comes out of the
nipple.
Junction Box
The junction box allows you to install the detector at a mounting site that is remote from a
controller and it protects the detector wiring connections. Two 3/4” NPT conduit hubs
allow you to mount the detector to the junction box and connect the wiring from the
detector to a controller. The terminal block within the junction box facilitates the wiring to
the detector. A cover on the front of the junction box allows access to the interior of the
junction box. Three spacers installed on the back of the junction box control the distance of
the junction box from a mounting surface and insure that there is enough room to install a
calibration cup on the detector during calibration.