Tweco PAK 10 - Manual (Page 30)

Service 18 Manual No. 0-0515
WARNING
Disconnect primary power before installing the
leads extension package. Do not turn on pri-
mary power to unit until all connections are
made and insulators are in place.
The leads that are furnished with the extension pack-
ages are the same as standard leads with the exception
of the control switch leads for the hand torch. On the
extension package the control switch leads terminate
in a receptacle for the 2 prong “Twist-Loc” plug. The
standard leads have a square plastic connector that
mates with the one on the torch leads.
NOTE
For leads extension over 100 feet the two-second
gas purge is not adequate. Replacement of TD2
Relay (Catalog No. 9-2694) with a Catalog No.
9-3528 Relay will increase the purge time to ten
seconds.
4.3 PAK UNIT MAINTENANCE
The only routine maintenance required for the PAK 10
system is a thorough cleaning and inspection of the unit.
This should be done on a regular basis, the frequency
depending on the amount of usage and the environ-
ment in which the unit is operated.
WARNING
Removing the cover of a PAK 10 with a Run-
ning Gear also removes the retaining chains
making the gas cylinder free-standing. This cyl-
inder must be restrained by some temporary
means until the cover and retaining bar are re-
placed and the retaining chains reconnected.
To clean the PAK unit, first make sure that the power is
disconnected and AC Power Light (LT1) off. Remove
the cover and side panels of the unit and blow out any
accumulated dirt and dust with compressed air. The
unit should also be wiped clean. If necessary, solvents
that are recommended for cleaning electrical appara-
tus may be used.
While the covers are off, inspect the wiring in the unit,
looking for any frayed wires or loose connections that
should be corrected. When cleaning the unit pay par-
ticular attention to the area around the high frequency
spark gap points since accumulated dirt in that area
can weaken the high frequency starting current.
4.4 GAS PRESSURE
REGULATORS
The Thermal Arc gas pressure regulators provide a
means of conveniently selecting and maintaining the
required working pressures of the gases. The regula-
tor will hold this pressure constant. Inlet pressure is
reduced in one step to the working pressure by means
of a pressure balanced poppet valve controlled by a
spring loaded piston in a low pressure chamber. A large
adjusting knob (6, Figure 4-E) provides for adjusting
spring pressure against the piston. A sintered stainless
steel filter, in the inlet connector (1), prevents dirt from
entering the regulator mechanism.
No regular maintenance of the gas pressure regulators
is required, except an occasional lubrication of the ad-
justing screw thread and on its end, where it contacts
the adjusting spring. Lubricant is available from Ther-
mal Dynamics for this purpose (Catalog No. 9-2871).
Replaceable parts in the regulator include the pressure
gauges, the O-ring seals on the piston and above the
poppet valve, and the poppet valve. (See Assembly
Parts List Fig. 5-10 for replacement parts).
CAUTION
Do not attempt to remove the sintered metal fil-
ter in the inlet connection. This is not a service-
able item.