I-UDSA-UK (02-19) PN 06 00116 UDSA R3, page 14
Burner gas pressure adjustment
The gas pressure is set for the required heat input before the
appliance leaves the factory. Provided that the gas supply
to the air heater is in accordance with the supply pressure
described on the appliance data plate, the operating pressure
will not require adjustment. To check the pressure use the
following procedure:
* Ascertain correct operating gas pressure from heater’s
data plate
* Adjust room thermostat control to its lowest setting
* Remove screw from burner pressure test point of multi-
functional control valve and connect manometer to test
point (see Figures 9 and 10)
F
igure 9 : Gas valve (models 011-4E
→
043-4E)
Legend
:
1) Shut-off solenoid valve EV1
2a) Adjustment high fire (large nut)
2b) Adjustment low fire (small nut)
3) Inlet pressure test point
4) Outlet pressure test point
5) Shut-off solenoid valve EV2
6) Pilot outlet
7) Main gas outlet
8) Holes (M5) for fixing flanges
* Adjust room thermostat to call for heat (i.e., above room
ambient temperature)
* Observe burner gas pressure on manometer and compare
to required pressure on data plate
* If necessary, adjust burner gas pressure (only for natural
gas) by removing cover from regulator and turning regulator
screw anti-clockwise to decrease pressure or clockwise to
increase pressure
* Set room thermostat to lowest setting to turn OFF burners
* Replace test point screw/cap and use leak detector fluid
with main burner OFF to test for gas soundness
* Reset temperature control/room thermostat to comfort
operating level
F
igure 10 : Gas valve (models 050-4E
→
145-4E)
Table 8 : Burner jets and pressures
Diameters/Pressures
UDSA-4E
011
015
020
025
030
035
043
050
055
064
073
085
100
120
145
Natural Gas (G20)
*
Burner jet diameter (mm)
3.20 3.70 4.20 4.80 5.30 5.75 6.50 6.80 7.10 8.00 7.40 8.90 10.00 8.00 7.40
Burner pressure, high (mbar) 7.90 7.80 7.10 8.20 7.50 7.90 7.10 7.90 8.40 7.90 12.00 8.00 7.10 7.85 12.00
Burner pressure, low (mbar)
2.00
1.80 2.10 1.90 2.00 1.80 2.00 2.10 2.00 3.00 2.00 1.80 2.00 3.00
Propane (G31)
**
Burner jet diameter (mm)
1.70 1.95 2.15 2.60 2.80 3.10 3.35 3.70 3.90 4.15 4.50 4.90 5.20 4.15 4.50
Burner pressure, high (mbar)
36.90
36.80
36.00 35.90 35.80 35.70 35.60 35.10 34.60 34.50 34.80 34.40
Burner pressure, low (mbar)
15.60
15.20
15.10
15.00 14.80
14.60
14.70 14.50
*
Inlet pressure = 20 mbar. Low fire is 50% full rate.
**
Inlet pressure = 37 mbar. Low fire is 65% full rate.
2b
2a
1
5
3
4
8
7
6
Legend
:
1) Shut-off solenoid valve EV1
2a) Adjustment low fire (large nut)
2b) Adjustment high fire (small nut)
3) Inlet pressure test point (not visible on Figure 10)
4) Outlet pressure test point (not visible on Figure 10)
5) Shut-off solenoid valve EV2
6) Pilot outlet
7) Main gas outlet
8) Holes (M5) for fixing flanges
2a/2b
1
5
7
8
6
3
4
Instructions for gas conversion:
To convert the heater to/from natural gas (G20) or to/from propane (G31), refer to burner gas
pressure adjustment (above) and perform the following steps:
* Using hex wrench, adjust burner jet to corresponding burner diameter listed in Table 8
* Adjust burner pressure to corresponding burner pressure listed in Table 8
* Check inlet pressure as listed below
