Operating Instructions
1. Introduction
The UNILOW FURNACE No. 1365 is a non domestic portable high output furnace for use with
propane at 0.35 – 1 bar pressure. The wide low frame gives good
stability. It is fitted with an adjustable air intake to allow
for a wide range of flame patterns ranging
from soft to vigorous and the burner design
prevents the jet from being easily blocked by
spillage. It is ideal for melting lead and other
metals, compounds bitumen, etc. The furnace
is fitted with a needle valve, it is also supplied
with a hose tail end suitable for fitting to 4.8 bore
LPG hose to BS 3212/2 (high pressure). To get the
best results from the furnace it should be used in
accordance with these instructions and the
enclosed safety precautions leaflet giving
general advice on the safe use of LP
gas.
2. Ventilation and free space
Use only in a well ventilated area. The
minimum room size for the Standard Furnace
should not be less that 126m3(4453 ft3) with a free
ventilation area of more than 315 cm2(49 in2) divided equally between high and low levels. This
free space and ventilation area are in addition to those required for any other gas appliance and
occupants of the room.
3. Positioning
Care should be taken to position the furnace so that it cannot overheat the gas cylinder (3m
minimum distance) or any other combustible surface or wall (300 mm minimum distance). Avoid
twisting or kinking the flexible hose. Do not use aerosols, paints, glues or other flammable liquids
in the same room as the furnace. Do not use in basements or below ground level.
4. Gas supply
The furnace requires a propane gas supply at 1 bar (15 psi) regulated pressure. Minimum
cylinder size 13 kg. Use a high pressure propane regulator, either pre set to 1 bar or variable up to
1 bar (Bullfinch Variable Tinyreg No. 1051/01 is suitable) and at least 3 m of high pressure 4,8
bore LPG hose to BS 3212/2 (Bullfinch No. 1299).
4.1 Connection to the gas supply
1 Fit hose to regulator and hose connector and secure with suitable hose clips.
2 Check that the regulator connection and the inside sealing face of the cylinder valve are clean
and undamaged, connect the regulator to the cylinder and spanner tighten the nut. It has a
left hand thread.
3 Check that the hose is not twisted or kinked and is secured to the fittings at both ends with
the appropriate clips and that the gas connections are tight. Ensure that the furnace valve is
in the off position and turn on the gas at the cylinder valve and if required adjust the
pressure regulator to 1 bar.
4 Check for gas leaks using a soap solution or leak detecting fluid as described in the Safety
Precautions. Do not light the furnace if it is leaking but turn off the cylinder valve and have
the furnace serviced. Never search for gas leaks with a naked flame.
5 When changing gas cylinders always ensure that there are no naked flames in the area. Check
that the cylinder valve is closed before disconnecting or reconnecting the furnace.
4.2 Lighting the furnace.
1 Adjust the pressure regulator to 1 bar and turn on the cylinder valve.
2 Open the flame adjuster by turning the knurled collar to allow maximum amount of primary
air into the mixing tube.
3 Open the furnace valve slightly to allow a small flow of gas to the burner and apply a flame
to the top edge of the burner, once the burner is lit open the valve fully. The flame should
burn fiercely without a yellow tip, with a dark blue outer mantle of approximately 270 mm
long with a lighter blue inner cone of approximately 120 mm long.
4 The flame pattern can be softened by using the knurled flame adjuster to close off the amount
of primary air to the burner. Progressive loss of primary air to the burner causes the flame to
become less fierce with less definition to the outer and inner cones, the flame will also burn
with a yellow tip.
5 If a variable regulator is being used, the heat input can be varied by reducing the pressure at
the regulator.
6 After use turn the furnace off using the gas cylinder valve and allow the flame to die away
before closing the furnace valve. Do not turn on the cylinder valve again until the furnace is
about to be used.
If you are in any doubt about the use of the Standard Single Furnace, turn off the gas at the
cylinder valve and consult your dealer.
5. Technical data
Section 2
Maintenance and Servicing Instructions
6. Routine maintenance
The following routine maintenance checks should be carried out at regular intervals or if the
furnace has not been used for a year or more.
6.1 Cleaning.
When the furnace is cold wipe exposed metal surfaces with a damp cloth. Occasionally,
especially if the furnace has not been used for some time dust or insect debris may become
lodged in the burner or the tube, this may be removed by blowing through the tube with a
high pressure air line.
6.2 Gas soundness
Check the soundness of all gas joints with a leak detecting fluid (Bullfinch No. 550) and
rectify all leaks before lighting the furnace.
Never search for gas leaks with a naked flame.
6.3 Operation.
Light the furnace in accordance with the operating instructions and ensure that it ignites and
burns correctly.
6.4 Controls.
Check that the furnace valve operates without force and that it always closes off the gas flow
to the burner when it is turned to the closed position.
7. Servicing
Important: Servicing should only be carried out by trained and competent service agents. After
servicing or replacement of any part, check for gas leaks and correct operation before returning
the furnace to the user.
7.1 Burner. To replace the burner tube assembly:
1 Unscrew the burner assembly from the mixing tube elbow.
2 Refit new burner assembly.
7.2 Gas Jet. To clean or replace the gas jet (size 90):
1 Retract the flame adjuster to give maximum aeration.
2 Unscrew the jet from the jet carrier and clean or renew.
