page no. 24 of 36
NVS Range Users, Installation & Servicing Instructions Doc Ref M102 issue 2.4 May 2018.
2.6.6.1.2. High/Lo Regulator
Cover
Lever point
Hexagonal
adjustment screw for
maximum pressure
setting
Internal slotted
adjustment screw for
minimum pressure
setting
1. Set external controls to ensure the main burner is off.
Open the side access panel. Connect a pressure gauge to
the burner pressure test point on the multifunctional
control.
2. Set external controls to turn on the main burner and
maintain high fire. Compare the measured burner gas
pressure to that stated on the data plate. In addition it
is advisable to check the gas rate using the gas meter
dial pointer ensuring that no other appliances supplied
through the meter are in operation.
3. Repeat 2 above with external controls set to maintain
low fire.
4. If it is necessary to adjust either the high fire or low fire
pressures proceed as follows after levering off the plastic
cover from the Hi/Lo regulator.
Note: High fire setting must be adjusted first
after which the low fire setting can be set. Any
adjustment of the high fire setting alters the
minimum setting.
Maximum Setting
With the controls set to high fire use an adjustable or 8mm
spanner to turn the adjustment screw for high fire pressure,
clockwise to increase and counter-clockwise to decrease,
until the required pressure is obtained. Turn the burner On
and OFF several times to check the pressure setting and
then turn off.
Minimum Setting
Disconnect electrical connection of high/low regulator and
turn burners back on and wait until the burner pressure has
stabilized. Use a screwdriver to turn the slotted adjustment
screw for low fire pressure, clockwise to increase and
counter-clockwise to decrease, until the required pressure
is obtained. Reconnect high/low regulator and check high
fire pressure. Repeat both steps if necessary and then
replace cover cap.
stated on the data plate. If necessary adjust the burner
gas pressure by turning the regulator screw anticlockwise
to decrease the pressure, or clockwise to increase the
pressure.
3. 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.
4. 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.
5. Turn off the main burner and disconnect the pressure
gauge and replace the sealing screw. Turn on the main
burner as above and test for gas soundness around
pressure test joint using a leak detection fluid e.g. soap
solution.
Governor adjustment screw under cover cap
(Honeywell VR4605AB1027)
Fitted to the NVS 30, 60, 90
Governor adjustment screw under cover cap (Honeywell
VK425AB1007)
Fitted to the NVS 140
