SERVICE TIPS Unitary Products Group

5005 York Drive

Norman, OK 73069

877-874-7378

DATE: June 26, 2007 ST-014-07

TO: All York Branches and Distributors

All York Service Managers

All Field Service Supervisors

SUBJECT: Economizer Troubleshooting

Units: D*CE036-060 180-300, D*CG036-060 180-300, DH036-060 180-240, DHE036-060

180-240, DHG036-060 180-240, DM036-072 078-150 180-300, DJ036-060 180-300,

DR090-150 180-300, D*EE036-060, DF078-120, ZJ180-300, WJ180-300,

WR180-300

AIR CONDITIONERS

BP036-072 078-150 180-240, XP036-060, BQ036-060, B*CH036-060

HEAT PUMPS

We have received several calls concerning economizers. This “Service Tips” letter is simply a guide to use in order

to minimize parts changing without correct diagnosis. Knowing how an economizer works as well as inputs and

outputs can be very helpful when troubleshooting or setting up new systems.

Economizer Troubleshooting

Part numbers:

C7400 S1-03100863000

M7415 S1-02526250700

W7549 S1-03100862700

DAS S1-03100878001

The above information should assist in understanding operation of economizers and its components for the models

listed.

Sincerely,

Ken BlakleyKen BlakleyKen BlakleyKen Blakley

Ken Blakley

Field Service Supervisor