Xylem H-3551 - Manual (Page 6)

1-2 Introduction
H-3551
1.2 How it Works
The H-3551 has a motor driven compressor which maintains pressure in a small tank. Gas flows from the
tank through a precision restriction to the output port. The pressure across the restriction is measured with
a pressure transducer. By turning the compressor on and off, the micro controller attempts to maintain a
constant pressure across the restriction. Thus maintaining a constant gas flow. The micro controller also
compensates for the effects of gas density change with temperature to maintain a constant flow through the
restriction.
1.3 Unpacking the H-3551
You should have received the following items:
1. W ATER LOG ® Series H-3551 "Smart Gas" system
2. RS-485 Communications/power Cable
3. Installation Kit
4. This Owner’s Manual
Please verify you have received these components and any other optional equipment you may have ordered.
It is recommended that you visually inspect inside the H-3551 enclosure to verify all electrical connections
are secure, where some movement may have occurred during shipment.
1.4 Testing the System
Before installing the H-3551, you may wish to test the system in the shop or lab. This will familiarize you
with the instrument in an environment where it is easy to work and you are near a telephone if questions
should arise.
If you are unable to get the H-3551 up and running, refer to Chapter 2 (Installation) and Chapter 4
(Trouble Shooting). If you have further questions, feel free to call one of our support personnel at (435)
753-2212 for assistance.