Looking after your flue gas analyser

Zeichen setzen fürto the future
Committing die Zukunft

Looking after your Flue Gas Analyser

Committing to the future

Domestic Flue Gas Analysers
• How to get the best out of your Testo portable combustion analyser

Most electronic portable combustion analysers
have eight common components:

•Probe
•Pump
•Condensate trap
•Particulate filter
•Gas Sensors (O2, CO)
•Power supply (batteries)
•Circuit board (PCB) including a display. Often with a
pressure sensor and differential temperature capabilities
as well as IR senders to link with printers or a PDA
• Printer

testo AG, Title (version), author, date, confidentiality 2/7


• Flue Gas probe

The majority of flue gas probes incorporate a type ‘K’
thermocouple for the measurement of temperature.
They are designed so that the thermocouple end is
protected yet can still come into contact with the flue
gas.
For accurate measurement the thermocouple should
not touch the protective casing.




The most common failure of thermocouples is due to
damaged probe tips.

Most common cause of “false” readings is due to the
incorrect alignment of the probe in the flue. Also
having the charger connected when making a
measurement.

Always test with a warm flue to allow the boiler to
settle at the highest level of CO2. Wait until the flue
temperature and CO2 are steady before you accept
the reading as true.



Take good care of your Analyser



• Filters

Filters are designed to remove particulate
matter from the flue gas sample before it enters
the pump and passes across the gas sensors.
It is important that the filters are changed
regularly, Particularly on oil boilers. If the filter
is wet replace with a dry one, and remove
droplets of condensation from the probe filter
housing with a tissue.
Check the particle filter of the flue gas
probe for contamination at regular
intervals: check visually by looking
through the window of the filter
chamber. Replace the filter if there are
signs of contamination.
Example of a dirty filter used on oil
against a clean filter



• Analyser pump
Any reduction in the flue gas sample rate
results in a slow response from the gas
sensor. This comes from:

Blocked particulate filters

Pumps exposed to flue gas condensate
Condensate traps full of water

You can hear when the pump is labouring
or not working efficiently.

Pump



• Emptying the condensate trap
It is important to ensure that condensate trap is emptied on a regular basis.

Failure to empty the condensate trap will result in
moisture being drawn through the instrument and
causing premature gas sensor failure.
There is a sight on the sides of the instrument to check
condensate levels.
It is good practice to empty the trap after each use

It is good practice NOT to leave your analyser with the
pump running and the probe in the flue, when not
observing readings. This unnecessarily pulls water
vapour in runs the battery down and exposes the
analyser to high CO if the boiler cycles off to on.

Despite built in protection against high CO,
incorporated in the 327 analyser. Damage can occur if
the displayed warning is ignored. Remove and Purge
in fresh air.



Take good care of your analyser



• Gas sensors

Gas sensors within portable combustion analysers normally fail due to their age
not the amount they are used i.e. the chemical reactions deplete in time rather
than the number of times the analyser is used.
• But, they can also fail due to exposure to moisture (flue gas condensate) and
exposure to high gas concentrations (CO)
• Low temperatures can lead to the impression of a failure as this effects the
chemical reaction within gas sensor.
• Do NOT leave your analyser in the cold over night, condensation will form and
can temporarily stop the sensors from calibrating.




• During winter months keep equipment above
5°C. DO NOT store in vehicles overnight
• Excess Carbon Monoxide (>4,000ppm) sampled
by the analyser can damage the CO gas sensor.

• ALWAYS remove condensate from the trap
before storage to prevent migration to gas
sensor membrane or pump
• DO NOT operate for long periods at high
concentrations (CO) as this will poison the
sensor




• Circuit board
Circuit boards within analysers are robust in construction but are prone to damage if
they dropped or treated without care.




• Printer
The printer has a thermal printing
mechanism and as such is susceptible
to heat. If the printer is placed in a
particularly hot environment it may
effect the quality of the print.
Also, the printer mechanism requires
replacement print paper to be fed
carefully through the mechanism.
Do not force or pull paper through the
mechanism with excessive force.
The other common problem is with
printer batteries. Always use good
quality batteries, never leave them in
the printer for extended periods and
always make sure that they are fitted
correctly.



• Power supplies / Batteries

The analyser must not be connected to the
charger when making measurements.
 The measuring instrument must be switched
off for charging.



• To summarise:
• Flue Gas Analysers are expensive measuring instruments that benefit from good
house keeping and regular routine maintenance.
• Excess Carbon Monoxide >4,000ppm sampled by the analyser can damage the
gas sensor.
• Never leave the analyser unattended whilst taking a flue sample.
• If the sensors are exposed to water, there is a high risk of damage.
• Maintain a dry water trap to prevent water damage. Also condensation sits in the
probe hose, remove by tipping probe downwards, dispose of safely as the
condensate is slightly acidic.
• The filter in the probe can get wet, particularly on condensing boilers. Simply
detach filter and replace with a dry one.
• Prevent storage of instrument in subzero temperatures as the electrolyte solution
in the sensors will freeze and measurements can not be taken. The sensors will
return to normal as the ambient temperature rises above zero.
• Inspect your flue probe and hosing regularly for damage and ensure that the flue
probe thermocouple in the probe tip is protected.



Analyser messages
• High CO level purge in fresh air
• O2 sensor depleted
• CO sensor depleted
• Ambient temperature sensor not working?


Looking after your flue gas analyser

Recommandé

Recommandé

Contenu connexe

Plus de Testo Limited

Plus de Testo Limited (20)

Dernier

Dernier (20)

Looking after your flue gas analyser