7.4. Checking the combustion circuit seal
Check for leaks with a foaming product. The areas
to be checked are shown in the figure opposite.
The check should be carried out when the appliance
is cold (water heater turned off) but with the fan at
maximum speed (obtained by disconnecting the
PWM signal connector - see electrical diagram).
If you detect any leaks, you must replace the seal
with the adapted kit.
We recommend replacing the seals each time it
is opened.
7.5. Checking the combustion quality
This check is carried out with a calibrated
combustion kit. To do so, insert the measurement
rod into the fume nozzle (see figure opposite).
The water heater setpoint must be equal to or
greater than 65°C.
IMPORTANT:
Do not forget to put the cap back on the sampling plug opening after
the measurement.
The CO
2
content measured under these conditions must be within the
values indicated in the table on the end of section 7.6 (depending on
the type of gas and the Dorchester DR-SG model).
If this is not the case, you must readjust the gas valve (see next §).
Following this check, you must take a "gas start" flow rate measurement. This
measurement is used to check the dirt build-up on the combustion circuit.
The "gas start" must be made for a period over 3 minutes to obtain a
satisfactory level of accuracy.
If the gas flow rate is 20% lower in relation to the value indicated in the table
in paragraph § 3.3, you must clean the burner (see § 7.7).
figure 20 - Sampling plug
Fume sampling plug
opening
figure 19 - Combustion leaks
Zone to be
checked
Page 46 / 104
00U07337760-A
DORCHESTER DR-SG -
Installation, Operation and Maintenance