L31103
Rev. 8/99
INSTALLATION INSTRUCTIONS
PURE AIR PLUS AIR DRYER
12 VOLT (N4250/DA33100)
24 VOLT (N4250A/DA33110)
CONNECTING THE HEATER
1.
Determine the vehicle's electrical system voltage and make certain that
the Pure Air Plus Air Dryer installed is of the same voltage.
2.
Connect the white lead from the dryer to a good ground on the vehicle chassis.
3.
The black lead should be attached to a wire which is hot when the ignition is "on."
A ten (10) amp fuse is recommended in this wire for a 12 volt dryer and a five (5) amp
fuse for a 24 volt dryer, in addition to the vehicle circuit breaker for that wire. Also the
"hot" wire from the vehicle should be a minimum of 14 gauge.
OPERATIONAL CHECKS
Once the unit is installed, start the engine, build up pressure to 100 psi, and shut off
the engine. Check for air leaks at the inlet and outlet of the dryer. Correct any leakage
problem. Restart the engine and build up pressure to compressor cutout pressure. At
cutout pressure the dryer purge valve opens and immediately expels a large volume of
air, followed by a slow flow of air lasting approximately thirty seconds. Check for
leakage at locations shown below to assure that the Pure Air Plus Air Dryer does not
cycle excessively. Monitoring wet tank pressure with an accurate air pressure gauge
will help determine if a significant air leak is present.
A. Compressor Unloader Mechanism.
B. Governor and associated fittings and air lines.
C. Drain Cock and Safety Valve in first (supply or wet tank) reservoir.
D. All air connections and air lines leading to and from the first (supply
or wet tank) reservoir.
DESICCANT CANISTER REMOVAL
(Note: Do not remove the Desiccant Canister until the wheels have been blocked and
the system has been drained of all pressure.) To check the condition of the coalescing
filter, carefully loosen the desiccant canister and spin off by hand. To reinstall the
canister, spin on by hand to contact, then turn by hand 1/2 turn past contact. (10 - 20
lb. ft., 14 - 27 Nm.)
APPLICATION GUIDELINES
The Pure Air Plus Air Dryer is designed to remove sufficient water, dirt, and oil during
normal highway applications. Unusual or severe duty applications such as trash
haulers or yard jockeys may have excessive compressor load cycles or insufficient
unload cycles. Either case will reduce the performance of the dryer.
For optimum performance the Pure Air Plus Air Dryer must have a minimum of thirty
seconds purge time between compressor load cycles, and the compressor load cycles
should average no more than eighty seconds.
Rev. 8/99 50M CM L31103
North American Sales Division
Haldex Brake Products Corporation
10707 N.W. Airworld Drive
Kansas City, Missouri 64153-1215
Phone: (816) 891-2470
Fax: (816) 880-9766
North American Sales Division
Haldex Limited
525 Southgate Drive, Unit 1
Guelph, Ontario CANADA N1G 3W6
Phone: (519) 826-7723
Fax: (519) 826-9497
Commercial Vehicle Systems
www.haldex.com
◆
www.hbsna.com
