TPI 708 Manual Download Page 13

Page: 13 / 44

COMBUSTION ANALYSIS OVERVIEW

Performing combustion analysis is very important to the overall safety and
efficiency of heating equipment. The following guidelines and descriptions are
generic and meant to provide you with a basic understanding of combustion
testing. TPI always recommends you contact the manufacturer of the device
under test, obtain information specific to the device, and follow the proce-
dures and safety guidelines for performing tests and affecting repairs.

In general, for most applications, flue gas samples should be taken prior to
the draft diverter or any other opening that allows room air to enter the sys-
tem. This prevents room air from mixing with gases in the flue and diluting
the test sample. To ensure accurate and consistent combustion tests, it is
important gas and temperature samples be taken at the same location. This is
easy with the TPI flue probe because the temperature sensor is an integral
part of the probe.

Prior to taking a sample, the device under test should be on and operating.
Putting the flue probe in the sample area prior to starting the device may
cause saturation of the sensors due to the higher initial concentration of car-
bon monoxide that may be encountered upon start up. If this happens, allow
your analyzer to purge in fresh air until the carbon monoxide level returns to
0 ppm and the oxygen level returns to 20.9%. This may take more than an
hour depending on how saturated the sensors are.

The figures on pages 13 through 15 show locations for performing tests on
commonly encountered equipment. Remember to consult with the manufac-
turer of the device under test for specific test information.

Pressing the Func Key enables access to the different functions available on
the 712. The default function is Combustion Analyzer. Other available func-
tions are: Thermometer, Manometer/Tightness Test, Combustible Gas Leak
Detector, and Date / Time display.

Refer to the Appendix G “Technical Notes” for additional information.

Combustion Analyzer

(Default Start Up Mode)

COMBUSTION TEST PROCEDURE

Note: It is recommended you perform routine general maintenance on your
analyzer to ensure proper function. Please refer to Appendix A for general
maintenance schedule and function tests.

1. Turn the 708 on in fresh air as outlined on page 8. After the initial purge
cycle the 708 will default to combustion analyzer mode and combustion dis-
play 1 will be seen.

•

Combustion Display 1 (Default Start Up Display)

• Displays Carbon Monoxide (CO) reading in parts per million

(ppm)

• Displays calculated Carbon Dioxide (CO2) figure in percentage

(%)

• Displays calculated CO/CO2 (Ratio) figure

2. Connect the Mini Pump Protection Filter assembly and Flue Probe Tubing
complete with In-Line Filter to the Gas Sample Port and the 'K' Type
Thermocouple Plug from the Flue Probe into Thermocouple (T1) Socket. The
GK11M ambient air temperature probe is connected to the (T2) socket. (See
below & page 7)

WARNING

: - Ensure the 'K' type thermocouple probes are inserted into the

sockets correctly (see page 7). The plugs are polarity marked and forcing the
plug into the socket the wrong way may result in damage to the
instrument.

Mini Pump
Protection Filter
Assembly

Ambient Air
Connection (T2)

GK11M Probe

Flue Probe
Connection (T1)

In-line Filter
Assembly

Flue Probe
Tubing