
8514-272-002 Rev PR page 13
CAUTION: The dryer and its individual shutoff valve must be disconnected from the gas supply piping system
during any pressure testing of that system at test pressures in excess of 1/2 psig (35 mbar). The dryer must be
isolated from the gas supply piping system by closing its individual manual shutoff valve during any pressure testing
of the gas supply piping system at test pressures equal to or less than 1/2 psig (35 mbar).
6. EXHAUST INSTALLATION. Exhausting of the dryer(s) should be planned and constructed so that no air
restrictions occur. Any restriction due to pipe size or type of installation can cause slow drying time, excessive
heat, and lint in the room.
From an operational standpoint, incorrect or inadequate exhausting can cause a cycling of the high limit thermostat
which shuts off the main burners and results in inefficient drying.
Individual exhausting of the dryers is required. All heat, moisture, and lint should be exhausted outside by
attaching a pipe of the proper diameter to the dryer adapter collar and extending it out through an outside wall.
This pipe must be very smooth on the inside, as rough surfaces tend to collect lint which will eventually clog the
duct and prevent the dryer from exhausting properly. All elbows must be smooth on the inside. All joints must
be made so the exhaust end of one pipe is inside the next one downstream. The addition of an exhaust pipe
tends to reduce the amount of air the blower can exhaust. This does not affect the dryer operation if held within
practical limits. For the most efficient operation, it is recommended that no more than 14' (4.25m) of straight 8
in. (203mm) diameter pipe be used with two right angle elbows. The design of the vent system shall be such
that any condensate formed when operating the dryer from cold shall either be retained and re-evaporated or
discharged.
Maintain minimum 1 in. (25) clearance between duct and combustible material.
If the exhaust pipe passes through a wall, a metal sleeve of slightly larger diameter should be set in the wall and
the exhaust pipe passed through this sleeve. This practice is required by some local codes and is recommended in
all cases to protect the wall. This type of installation should have a means provided to prevent rain and high winds
from entering the exhaust when the dryer is not in use. A hood with a hinged damper can be used for this purpose.
Another method would be to point the outlet end of the pipe downward to prevent entrance of wind and rain. In
either case, the outlet should be kept clear, by at least 24 in. (610 mm), of any objects which would cause an air
restriction.
Never install a protective screen over the exhaust outlet.
When exhausting a dryer straight up through a roof, the overall length of the duct has the same limits as exhausting
through a wall. A rain cap must be placed on top of the exhaust and must be of such a type as to be free from
clogging. The type using a cone shaped “roof” over the pipe is suitable for this application.
Exhausting the dryer into a chimney or under a building is not permitted. The exhaust air should not be vented
into a wall, a ceiling, or a concealed space of building. In these cases, there is a danger of lint build-up which
can be highly combustible.
7. DRYER IGNITION (SOLID STATE IGNITION). The solid state ignition system lights the main burner gas
by spark. The gas is ignited and burns only when the gas-valve relay (in the electronic controller) calls for heat.
The procedure for first-time starting of a dryer is as follows:
A. First, review and comply with the “WARNINGS ABOUT USE AND OPERATION” found on the inside front
cover of this manual. Be sure the electrical power supply is connected correctly. The white (neutral) wire
is to be connected to the N terminal while the black (line) wire to the L1 terminal of the terminal block in
the rear control box. The dryer MUST be properly earthed.
B. Make sure all gas supply lines are purged of air. Close the main gas shut-off valve and wait for five minutes
before turning the valve back on.
C. Turn on main electrical power switch. The dryer may be started by following the “OPERATING
INSTRUCTIONS” found later in this manual.
D. Natural gas and liquefied petroleum gas fired dryers both operate in the same manner. When gas-valve
relay contacts are closed (indicating a demand for heat), the solid state ignition control will automatically