23
Installation and operation manual
–
DTHR-V9-2020
3.0
Burner adjustment
-
Install a
pressure gauge (0-10 in. w. c.) on the manifold pressure test port located downstream
of the modulation gas valve. See component identification section for location.
-
For the combustion test, it is recommended to use a (2-10VDC) manual potentiometer to
simulate the modulation signal to the burner.
-
Start the burner at the minimum voltage of 2.5 VDC and verify the flame stability. Take a
combustion reading before increasing to high fire.
-
Run the burner slowly to its maximum capacity (high fire) while looking to the combustion
tester to be sure to have good combustion and enough excess air.
-
Compare the manifold pressure with the name plate indication. Adjust the gas regulator if
needed to obtain the right value.
-
At high fire, you should have a combustion reading of 3-5% O
2
approx. and a CO reading close
to 0 ppm and never above 400 ppm of air-free CO.
-
The targeted oxygen % over the modulation is ±3 to 5% O
2
at high fire and ±18% O
2
at low fire
with a progressive curve between the two operation points. Note that the combustion results
when increasing capacity and decreasing are different (less oxygen % when decreasing).
-
If the readings are out of the range, use the
Air/Gas relation
window (level 1 menu) on the HMI
touch screen to adjust (see
Air/Gas relation
section on page 31).
Warning
Do not only adjust the flame visually. The use of an analyser and/or combustion instruments are the
only appropriate method to adjust the combustion burner.
