York Meridian Technical Manual Download Page 2

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Zone

How Meridian



Works ........................................................................................................... 5

Why Should I Use Meridian



? ............................................................................................... 6

What Is Unique About Meridian



? ...................................................................................... 6-8

Zoning Systems Versus True VAV Systems .......................................................................... 9

Basics Of Designing A Zoning System ................................................................................ 10

Design Considerations ................................................................................................... 11-12

Zoning Design Procedures ............................................................................................. 13-21

System Installation ......................................................................................................... 22-26

Application Notes ................................................................................................................ 27

Table Of Contents

NOTE: Any reference in this document to roof top HVAC units
are for ease of communication. Meridian



can also be used on

split systems.

Form: 036-21478-001 Rev. A (0802) Supersedes: Nothing

Meridian



is a registered trademark of York International Corp.

York International Corp. assumes no responsibility for errors, or omissions.

This document is subject to change without notice.

Summary of Contents for Meridian

Page 1: ... Zoning T T T T Tec ec ec ec echnical Guide hnical Guide hnical Guide hnical Guide hnical Guide Contr Contr Contr Contr Control Systems ol Systems ol Systems ol Systems ol Systems Form 036 21478 001 Rev A 0802 Supersedes Nothing ...

Page 2: ...plication Notes 27 Table Of Contents NOTE Any reference in this document to roof top HVAC units are for ease of communication Meridian can also be used on split systems Form 036 21478 001 Rev A 0802 Supersedes Nothing Copyright 2002 York International Corp Meridian is a registered trademark of York International Corp York International Corp assumes no responsibility for errors or omissions This do...

Page 3: ...ferred Sensor Location 17 Figure 1 9 Acceptable Sensor Location 17 Figure 1 10 Least Desirable Sensor Location 17 Figure 1 11 Pressure Dependent Damper 18 Figure 1 12 Pressure Independent Damper 18 Figure 1 13 York Communications Wire 23 Figure 1 14 Meridian Basic System Communications Loop Wiring 24 Figure 1 15 Meridian Plus System Communications Loop Wiring 24 Figure 1 16 Transformer Wire Sizing...

Page 4: ......

Page 5: ...tes the heating and cooling require ments for each zone based on real time information re ceived from each Zone Controller Damper The Zone Manager then directs the HVAC unit to provide the appropriate amount of heating cooling and ventilation to satisfy each zone s requirements A bypass damper controlled by a static air pressure sensor modulates to maintain constant duct pressure The Meridian syst...

Page 6: ...is allows a contractor with limited con trols experience to easily install the Meridian system Pre Engineered Software System design software and documentation has already been done for you This eliminates the costly expense usually associated with conventional DDC systems making the Meridian system more competitive and easier to install and operate One System for Zoned or Single Zone Systems Not ...

Page 7: ...unications interface and a local phone line With the Remote Link the Meridian sys tem can be monitored and controlled from a remote lo cation using a computer and the Prism computer front end software package Memory Backup Instead of batteries which have to be replaced Meridian utilizes super capacitors to provide power for memory backup during power outages The major advantages to this approach i...

Page 8: ...g side note about the auxiliary relay board and airflow sensors These devices are typically used on the zone controllers in the Meridian Basic Plus systems When the system is powered up it automatically looks to see if these de vices are connected to the controller If they are the controller automatically reconfigures itself to utilize these devices and activates the appropriate set up screens bac...

Page 9: ...lume ter minal units used to control the volume of constant tem perature air delivered to the space Generally these sys tems use pressure independent damper control Zoning Systems Versus True VAV Systems Meridian Systems The Meridian zoning system is completely different in operation and design from the VAV system previ ously discussed One of the major differences between the zoning system and a t...

Page 10: ...uld contact the factory When using auxiliary heat for individual zones perimeter heat such as baseboard is always preferred and more economical to operate than a fan terminal unit with reheat If you have electric reheat coils mounted on VAV boxes it is recommended that a fan powered box be used Consult the factory for further details concerning this application If there is an economizer on the HVA...

Page 11: ...conomizer on your rooftop unit The Meridian control system is designed to take advantage of an economizer if it is installed The use of an economizer will save money on utilities and provide comfort under conditions when it is not possible to operate the mechanical cooling sys tem 2 Low Supply Air Temperatures Under lightly loaded conditions much of the supply air may be by passed back into the re...

Page 12: ...ire it you may find that you can use a smaller unit in many cases Bypass the air into the ceiling plenum If you have a system without ducted return bypass the air into the ceiling plenum instead of into the return air intake This method works best with plenum returns Do not use this method with ducted returns Use auxiliary heat Use an auxiliary heat source in either your VAV boxes or use baseboard...

Page 13: ...s could be divided into multiple offices with full partitions between them thus requiring separate Zone Controllers because of differ ent internal loads but the same external load Generally the greater the number of individual Zone Controllers the greater the comfort The designer will have to look at the specific building balancing the costs of multiple zones with the added comfort possible with m...

Page 14: ...internal zones so they will have similar load requirements Figure 1 4 shows a building with 7 zones 4 of the zones have a north exposure and the other 3 have a south ex posure Since there is a big difference in the affect on the building between north and south exposures instal lation of two separate zoned HVAC units is recom mended Figure 1 5 shows a combination manufacturing facility and office ...

Page 15: ...feet and a maximum duct velocity of 2000 FPM Note For pressure independent terminal units with velocity sensors and conventional VAV boxes properly selected for quiet operation this 2000 FPM rule can be exceeded by up to 50 percent The designer however should be very experienced in VAV system design before considering modification of this general rule Typical VAV systems with pressure independent ...

Page 16: ...ss damper modulates on a signal from a duct static pressure sensor to by pass air from the supply duct back into the return air duct If the duct static pressure exceeds the adjustable setpoint then the damper opens to bypass more air and if the static pressure drops below the setpoint it closes to bypass less air Using a load calculation program the bypass damper should be sized to give you the ma...

Page 17: ...rmance without requiring a transi tion fitting One additional damper may be slaved together for large zones See zone wiring diagram for details This should be reserved for situations when it is not practical to use a single large damper Round zone dampers can be speci fied to be either pressure dependent or independent Fan RA Sensor SA Sensor 3D Min 2D Min Return Air Duct Supply Air Duct SP Pickup...

Page 18: ... or maximum airflow is maintained independently of the static pres sure available in the duct it is called pressure indepen Figure 1 11 Pressure Dependent Damper Figure 1 12 Pressure Independent Damper dent operation Pressure independent operation is avail able for round zone dampers only Pressure indepen dent rectangular dampers are not available See Figure 1 12 for a diagram of a typical pressur...

Page 19: ...ced Insulation Actuator Zone Controller Round Damper Blade Assembly Control Enclosure Cover Removed A IR FL O W A IR FL O W Table 1 1 Round Damper Selection Data Damper Round Duct Size Area Ft2 6 0 188 8 0 338 10 0 532 12 0 769 14 1 050 16 1 375 CFM 1 Velocity Pressure Air Flow Probe K Factor For Pressure Independent Applications Only 474 950 1417 2120 2908 3700 Velocity Through Zone Damper FPM Ai...

Page 20: ...0 0 01 2000 0 01 2080 0 01 12 560 0 07 650 0 05 730 0 03 850 0 02 970 0 02 1090 0 01 1210 0 01 1330 0 01 1460 0 01 1580 0 01 1700 0 01 1820 0 01 1940 2060 2190 14 660 0 05 770 0 03 880 0 02 1030 0 02 1180 0 01 1330 0 01 1480 0 01 1630 0 01 1760 0 01 1910 0 01 2060 2210 2360 2510 2640 16 750 0 04 890 0 03 1030 0 02 1200 0 01 1370 0 01 1540 0 01 1710 0 01 1880 0 01 2060 2230 2400 2570 2740 2910 3090...

Page 21: ...l lockout zone heat if the rooftop is delivering heated air Relay Expansion Board Outputs The following describes the operation of each of the relays on the optional relay expansion board The user can choose the appropriate relays for any given appli cation Relay 1 Parallel Fan If the Zone is in cooling or vent mode the parallel fan can activate anytime the zone temperature drops 0 5 F below the h...

Page 22: ...ble to power the system using one or more com mon transformers or individual transformers for each device Possible problems you may encounter using common transformers to power multiple devices are If polarity is not maintained between devices shorting of the transformer will occur resulting in damage to the electronics When using one transformer to power multiple devices it is possible to lose mo...

Page 23: ... should be color coded to facilitate error free wiring The communication loops will not work if any of the wires are reversed or otherwise landed incorrectly Com munications loops can be run up to a maximum of ap proximately 4000 ft in total length If your system ex ceeds this length please consult the York factory for more information regarding extended communication loop lengths and solutions Ca...

Page 24: ...COMM COMM R R YS101564 YS101564 EWDOG EWDOG 0 5 VDC 0 5 VDC 0 1 VDC 0 1 VDC CX6 SW1 U10 75176 EXPAN SION Q3 Q2 D3 VR1 7824 GND 24VAC M 7824C T MC340 64A 9936 R17 R16 U7 C7 R15 POWER R21 REV 2 YS101 562 MDL F1 250 D4 R26 LD3 L1 SCAN REC R12 C6 R11 TOKEN NET LD2 32 R14 R13 R100 LD1 C5 D1 K1 V2 fTimes New Roman b0 i0 c0 p18 G5L 114P PS 24VDC CONTACT UL CSA 5A250VAC fTimes New Roman b0 i0 c0 p18 OMRON...

Page 25: ... 2 Conductors 24 gauge minimum Outside Air Sensor 2 Conductors 24 gauge minimum Room Sensor 2 Conductors 24 gauge minimum 3 Conductors if using optional slide adjust Controller Wiring All controller wiring should be in accordance with all local state and national codes It is recommended that all wire be a minimum of 18 AWG unless otherwise specified in the charts below Controller connections and w...

Page 26: ...e to use one transformer to power all the controllers Next we must determine the maximum length of run allowable for the wire gauge we wish to use in the installation Each wire gauge below has a voltage drop per foot value we use to calculate total voltage drop 18ga wire 0 00054 voltage drop per 1 length of wire 16ga wire 0 00034 voltage drop per 1 length of wire 14ga wire 0 00021 voltage drop per...

Page 27: ...s please consult York Controls for assistance The 2ZEB004701024 8 Relay Staging Expansion Board is usually required as these units typically have more than 2 stages of cooling and heating Bypass dampers should be sized for 60 to 70 of the rated CFM of the unit Because of the large air volumes involved rectangular dampers should be used instead of round dampers Consult the rectangular damper sizing...

Page 28: ...ect to change without notice Printed in U S A Copyright by Unitary Products Group 2002 All rights reserved 036 21478 001 Rev A 0802 Supersedes Nothing Unitary Products Group 5005 York Drive Norman OK 73069 ...

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