page no. 33 of 48
LNVx Range Users, Installation & Servicing Instructions Doc Ref M104 issue 1.0 Sep 2018.
For Modulation a modulating control board is fitted (which
also includes the fan command outputs). The board
interfaces between a 0-10VDC control signal and the
modulating regulator.
Basic operation method
1. With the 0 to 10 signal at 0, the gas valve drive signal
will be de-energised.
2. When the input control signal goes to >2V, the gas valve
drive output will be at its maximum output value for a
preset 2 minutes.
3. An input signal from the burner controller - when
received by the board continually for more than 30
seconds - will switch an output to the main heater fan.
4. After the preset 2 minutes of maximum output, the 0
to 10V input signal will take control of the gas valve drive.
5. When the 0 to 10V signal drops below 1V the signal will
drop to zero and the gas valve drive signal will be de-
energised.
6. The fan output will continue for a further 2.5 minutes.
1. In addition it is advisable to check the gas rate using the
gas meter dial pointer. Ensure that no other appliances
supplied through the meter are in operation.
2. If required, after checking or setting the burner
pressures, the CO2 content in the flue gases can be
checked by sampling in the first section of flue fitted to
the flue outlet of the unit. Nominal CO2 values are given
for guidance in the table at the bottom of the previous
page.
3. Turn on the main burner as before and test for gas
soundness around pressure test joint using a leak
detection fluid e.g. soap solution. Replace access panel.
1. To measure the flame current connect a multimeter
capable of measuring micro amps as shown in the
following diagram.
Flame Current
Measurement
2. Minimum current reading is 0.5µA and normal value
should be 1.5µA or higher.
The running current of the centrifugal fan must be
checked once the heater is running and compared with
the following table.
Model
Pha Motor
kW
Typical
Running
Current
Max
Running
Current
LNVx15
1
0.25
2.0A
5.0A
LNVx20
1
0.42
3.1A
4.2A
LNVx25
1
0.42
4.2A
4.2A
LNVx40
1
0.55
5.8A
8.0A
LNVx45
1
1.1
7.6A
9.8A
LNVx50
1
1.1
7.6A
9.8A
LNVx60
1
1.4
9.8A
10.0A
LNVx70
1
1.4
11.0A
12.0A
LNVx90
1
2 x 0.55
6.4A
8.0A*
LNVx120
1
2 x 1.4
8.5A
10.0A*
LNVx140
1
2 x 1.4
10.0A
10.0A*
* current shown for each fan
WARNING: Exceeding the MAX running
current will cause the fan’s thermal overload
to trip!
Adjust the balancing dampers within the airflow ductwork
system to achieve a current suitable for the model in
question.