modular ahu manual

7/30/2019 Modular AHU Manual

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Instruction The Installation Part of this manual is intended for professional installers.

Read the Operation Part carefully before you install the unit to prevent

unit damage or accidents caused by your mishandling.

The contents of this manual may change with the update of certain models,

and no further notice will be given for such change.

Product standard: GB/T 14294-93


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Contents1. General ....................................................................................................... 1

1.1 Introduction ......................................................................................... 1

1.2 Nomenclature and Structure ............................................................... 1

1.3 Unit Model List .................................................................................... 1

2. Installation of Units ...................................................................................... 32.1 Preparation Before Installation ............................................................ 3

2.2 Check-and-acceptRiggingPortage ............................................... 3

2.3 Installation ........................................................................................... 4

2.4 Unit Connection................................................................................... 5

2.5 Other Instructions ................................................................................ 6

3. Operation and Commisioning ...................................................................... 7

3.1 Wiring Connection Check .................................................................... 7

3.2 Operation ............................................................................................ 8

4. Unit Maintenance ........................................................................................ 9

4.1 Regular Maintenance .......................................................................... 9

4.2 Precautions ....................................................................................... 10

5. Troubleshooting .......................................................................................... 11


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1. General

1.1 Introduction

The MKZII modular air handling unit is an air handling device which cools, heats,

humidifies, purifies and conveys air. The unit does not carry cool or heat source, and the

refrigerant is water or vapor. The unit provides the functional sections such as fresh return

air hybrid section, cooling coil section, heating section, low/mid/high-efficiency filter

section, electric heating section, humidifier section, resistance muffler section, heat

recovery, secondary air return section, fan section, and flow equalization section. The

user can select any combination of the functional sections to meet the requirements. The

air handling unit is widely applied to the central air conditioning systems in medium and

big buildings for electronics, textile and chemical fibers, precision instruments, metallurgy,chemical industry, pharmaceutics, food, tobacco, shopping malls and stadium.

1.2 Nomenclature and Structure

MKZ II 2124 A Z 1

MKZ :Midea Modu lar AHU

II :Designing Serial Code;

2124 :The width and length module is 24 21 respectively.Each module is

equal to 100mm;

A :No. of Coi l Rows,A = 4B = 6C = Other;

Z :Direction of Pipe Connection,Z Left-handedY Right-handed ,See

Note 1;

1 :Direction of Air Discharge,1 Vertical Discharge 2 Horizotal

Discharge;

Note 1:It is LEFT-HANDED pipe connection if the header pipe is on the

left-hand side when viewing from the air inlet.

1.3 Unit Model List

Note:The Detail Specification Please Kindly Check In The Catalogue.

Unit Model MKZ 0710 MKZ 0712 MKZ 08 12 MKZ 0814 MKZ 0915 MKZ 1118

Air Volume

m3/h

5000 6000 7000 8000 10000 15000

1


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Modular Air Handling Unit Installation & Operation & Maintenance Manual

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Unit Model MKZ 1418 MKZ 1620 MKZ 1623 MKZ 1826 MKZ 2127 MKZ 2131

Air Volume

m3/h

20000 25000 30000 40000 50000 60000

Unit Model MKZ 2631 MKZ 2635 MKZ 3136

Air Volume

m3/h

70000 80000 100000


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2. Installation of Units

The unit must be installed and implemented under GB50243-2002 Specifications for

Quality Acceptance of Ventilation and Air Conditioning Projects.

2.1 Preparation Before Installation(1) Get familiar with the relevant drawings and documents, and check whether the

installation site is readily available.

(2) Check whether the devices (or parts) and relevant accessories are complete.

Name Quantity Remarks

Installation and operationmanual of modular air

conditioning unit1 (Must be delivered to the user)

Customer service guide 1 (Must be delivered to the user)

(3) Prepare the conveyance devices (or components) and installation tools.

(4) Coordinate the installation progress of all parties to the project.

2.2 Check-and-acceptRiggingPortage

(1) If the integrated equipment is delivered to the destination, open the outer packageafter the unit, and Check the appearance quality of the product in the box and the

completeness of accessories. If any damage occurs, contact the logistics company

of Midea or claim against the carrier.

(2) If disassembled components are delivered to the destination, decide whether to

unpack first or convey the package to the site first.

(3) Convey the equipment according to the following figure in order not to damage the

unit in the conveyance and installation process.


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(4) If rollers are used for conveying the unit, use at least three materials longer than the

width of the unit.

(5) Handle with care and be cautious during the conveyance.

2.3 Installation

(1) The schematic diagram of installing the unit serves as a reference for the user.

(2) Enough maintenance space shall be reserved around the unit to facilitate daily

maintenance and upkeep of the unit. Note that at least 1m width shall be reserved in

the direction of setting up the overhauling door. The air system installer shall provide

the location dimensions of the direction for connecting the air duct.

(3) To install the unit, put the sections onto the foundation sequentially against the

drawing. For application sensitive to vibration, a damping cushion made of natural

rubber 10mm thick shall be applied between the unit and the foundation.

(4) If the unit is a small unit of the Company and needs to be installed in a suspended

way, the user shall allow for a maintenance space and a suspending weight.

(5) When connecting all sections of the unit, rubber plastic shall be used for sealing

between the sections.

(6) In the installation process, the installers shall pay attention to the weight-bearingcapacity of the unit and the panel.

(7) The procedure of installing the dry vapor humidifier is as follows: (The vapour spray

direction of the humidifier is opposite to air flow, and a drainage controller shall be set

at the vapour outlet).

(8) For any questions about installation, consult our technical department.


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2.4 Unit Connection

(1) According to the air volume and air pressure of this unit, select the proper ducts. The

ducts shall undergo heat insulation treatment. A straight pipe as long as at least

double length of the air outlet shall be reserved before the outtake duct is connected

from the air outlet to the elbow pipe.

(2) An air volume regulating valve shall be set at the intake duct and outtake duct for

ease of regulating the air volume of the system. flexible connection shall be set

between the unit and the outside.

(3) The top operating pressure of the cooling coil and the heating water unit shall not

exceed 1.6 MPa. Screws or flanges shall be applied for connection between the

lead-in water pipe and the lead-out water pipe. Thread seal tape shall be applied

around the pipe screws. The water pipes shall be led in from the top and led out from

the bottom, as shown in the following figure.

(4) When the maximum operating pressure in vapor heating is not greater than 1.4 MPa,

screws or flanges shall be applied for connection between lead-out water pipes. The

vapor is led in from the top and led out from the bottom. A drainage controller shall be

set at the vapor outlet. See the following figure.

(5) Regulating valves shall be installed for both lead-in water pipes and lead-out water

pipes of the unit (except the condensate pipe) for purpose of air volume regulation

and maintenance. The lead-in and lead-out water pipes of the unit shall insulate heat.

Necessary water seals shall be set on the condensate pipe. See the pipe diagram.

(6) Set a manometer and a thermometer on the lead-in water pipe and lead-out waterpipe of the unit for monitoring whether the water system is normal.

(7) All wire installation must adhere to the local power regulations. Before distributing the

wires, check whether the power supply and wires meet requirements against the

parameters on the nameplate of the unit.

(8) The power supply lead-in is located at the overhauling door side of the fan section

(unless otherwise required by the user). Connect the power wire to the motor junction

box of the unit.

(9) Configure the electric devices and wires according to the electric heating wire

diagram and the schematic diagram of the unit, and connect the wires correctly. Themetal enclosure of the electric heating coil pipe shall be well grounded. The

temperature relay signals in the electric heating coil pipe must be connected to the

electric heating controller center. This ensures that the electric heating power supply

will be cut off in case too high temperature of air in the unit. The electric heating

controller shall perform interlocked control for the fan and the electric heater, and

ensure that the electric heating power supply is disconnected when the fan stops.


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2.5 Other InstructionsAdopt flexible connection when connecting the external intake duct and outtake duct.

This prevents the vibration and duct weight from being borne by the unit.

In case of connecting external lead-in and lead-out water pipes, use flexible adapters.

Apply force equally when connecting the pipes. For piping of the vapor coil pipe, connect

the pipes according to the heating specifications in order to prevent the coil pipe from

being damaged by the heat stress. The intake and outtake pipes of various coil pipes

shall be connected as opposite to the air flow direction (the air flow direction shall be

inverse to flow direction of the refrigerant).

If a drain pipe is connected externally, connect the U-shape drain elbow first to

prevent difficulty of draining the condensate water caused by negative pressure in the unit.

The height difference of the water seal of the drain elbow may be twice as much as thenegative pressure in the unit. For the configuration of the foundation and the water seal,

see the following figure.

Both cooling and heating water shall be clean demineralized water. Before

supplying water, clean the water pipelines of the system and use the exhaust valve to

expel the air in the coil pipe completely.If the unit needs to stop operation in winter, be sure to keep continuous flow of the

water in the coil pipe, fill anti-freeze liquid, and close the fresh air valve to prevent freezing

of the coil pipe. If the unit needs to stop operation in winter for a long period, empty the

water in the coil pipe.


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3.Operation and Commisioning

3.1 Wiring Connection Check(1) The system should be correct and smooth without leak.

(2) The power wires shall be correctly connected, safe and tight. The motor of the unit

shall be connected to the power supply with phase loss protection and overload

protection. The startup of motors of over 11 kw shall be implemented through

potential fall. The motors of the unit shall under a one-to-one protection mechanism.

It is not allowed to connect two or more motors in parallel with the same protection

switch. Before connecting the power supply, check whether the voltage meets the

requirements, whether phase loss occurs, and whether the three phases are

balanced. After connecting the power supply, start the motor first to check whetherthe fan rotation direction is correct. If not correct, adjust the phase sequence.

W1V1U1

W1V1

U1

~M1

FR1

KM1

QF

L1 L2 L3 N

SB1SB2

KM1

FR1KM1


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(3) The air system is safe, reliable and correct. It is clean inside the pipe.

(4) No foreign matters exist in the fan, the fan VANE does not scratch the enclosure, and

the fan rotation direction is correct.

(5) If the integrated equipment is delivered out of the factory, remove the fixing block

beside the vibration absorber.

3.2 Operation

(1) This unit is designed according to the pressure and air volume required by the user.

Adjust the location of the damper as required, AND prevent a high pressure

difference between the inside and the outside of the unit because this will lead to

deformation of the unit.

(2) When supplying water to the unit, open the gas valve to expel air.

(3) In winter (especially in areas characterized by cold weather), the outdoor

temperature is low. Evacuate the water in the coil pipe or take proper protection

measures to prevent frost crack.

(4) For the unit with a humidifier, turn on the fan before giving out water (vapor); to shut

down the unit, stop the water (vapor) before turning off the fan.

(5) For the unit with an electric heater, the heater should be interlocked with the fan.

(6) To start the unit, turn on the fan before supplying water (vapor) to the coil pipe. To

shut down the unit, stop the water (vapor) before turning off the fan.

L1 L2 L3

QF1

QF2

N

M

KM1

FR

KM2

U1V1

W1

V2 W2U2

KM3

KM3

KT

KM3 KM2KT

KM1

FR

KM1

SB1

SB2 KM1

KM2

KM2KT


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4.Unit Maintenance

4.1 Regular Maintenance(1) During operation of the unit, observe the operation status of the fan regularly, and

check the belt tightness and the bearing conditions periodically.(2) The Rotation Power Momentum (RPM) of the fan depends on the required air volume

and the resistance caused by the accessories, the supply air and return air pipelinesystem of the unit. Such data can be used to determine the RPM of the fan accordingto the characteristic curve of the fan. The sheave and the belt specifications can bedetermined according to the required RPM and motor power. After the motor isstarted, adjust the resistance of the supply air and return air pipeline system toensure that the air is supplied evenly in the air conditioner room.

(3) By adjusting the location of the motor sheave and the fan sheave, let the belt beproperly tense (Figure 3). Press the belt with a finger, and the deformation size shall

be about 20 mm). Stop the fan during full-speed running. After stop of running, thestop time interval of the fan should be over 7 seconds.

(4) After the unit has run for a week, adjust the belt to the proper tenseness again.Afterward, perform a routine inspection every another month or every another two

months, and ensure that the results fall within the value range shown in the figure.Otherwise, adjust or replace the belt.

Note: Too loose and too tense belts will damage the system and increase noise.

(5) Rinse the filter (a) before the unit is started for the first time; (b) after the unit has runfor 3 months (in an average environment); or (c) an alarm is raised by the monitoringsystem. The procedure of rinsing the filter is: If the filter is cleanable, put the filter intoa neutral solution and scrub it gently, and reinstall it after sunning it dry. If the filter isnot cleanable, replace it. The non-woven fabric filter cannot be cleaned for more thanthree times, and the metal filter can be cleaned repeatedly.

(6) For the High Efficiency Particulate Air Filter (HEPA), install the filter in a clean indoorenvironment which must be airtight.

(7) Clean the surface of the coil pipe periodically. After the unit has run for 2-3 years,

Fig 3: Adjusting the tighteness of the V belt


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cleanse the pipe chemically to remove the incrustation scale in the pipe.(8) Check the electric devices periodically.

4.2 Precautions

(1) The supply air temperature of the unit cannot be greater than 80C.(2) The supplied water shall be dmineralized water. Generally, the lead-in cool water

temperature is about 7C and the lead-in hot water temperature is about 60C.(3) The unit shall work under rated air volume or rated current.(4) In case of low temperature, pay special attention to frost prevention.


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5. TroubleshootingCommon

faultLocation Possible cause Solution

Abnormalsound

1. Impeller

The impeller deviates from the

spindle.

The bearings become loose due to

too big spacing between them

The impeller becomes loose.

The spindle and the bearing sleeve

become loose.

The impeller is damaged.

The fan fastener becomes loose.

Foreign matter exists in the fan.

Contact the seller.

Contact the seller.

Contact the seller.

Contact the seller.

Contact the seller.

Tighten the screws.

Eliminate foreign

matters.

2. Conveyance part

The sheave is fastened on the

spindle.

The V belt becomes loose. Adjust it48 hours after the first operation.

The V belt is too tight.

The model of the V belt in use is

improper.

Multiple V belts in a unit have different

lengths.

The V sheave of the fan is not aligned

with the V sheave of the motor

properly.

The V belt is damaged.

The motor and the screws for

fastening the motor seat becomeloose.

Tighten the sheave.

Adjust the V belt

Adjust the V beltReplace the V belt.

Replace the V belt and

make the length

consistent.

Align the V sheave.

Replace the V belt.

Tighten the screws.

3. Bearing

Lube has run out.

The bearing sleeve becomes loose.

The unit is not installed in a level and

straight way.

Foreign matter exists in the bearing.

The bearing is damaged.

The bearing becomes rusted.

Apply lube

Tighten the bearing

sleeve.

Perform a reinstallation.

Eliminate foreign

matters.

Replace the bearing.

Remove rust or replace

the bearing.

4. Fan scroll case

Foreign matter exists in the scroll

case.

The scroll case becomes loose.

The air inlet scroll case is damaged.

Eliminate foreign

matters.

Contact the seller.

Contact the seller.

5. Electric partThe lead-in wire becomes loose.

The motor raises a resonant sound.

Phase is lost.

Tighten the lead-in wires.

Contact the seller.

Supply 3-phase power

6. Spindle

It becomes bent and deformed.

The counterbalance becomes loose.

The spindle becomes loose.

Replace the spindle

Tighten the

counterbalance.

Tighten the spindle.

7. Too high air speed

The duct is too small.

The practical static pressure does not

reach the designed static pressure

value.

Redesign the duct.

Change the V sheaves,

and reduce the fan

rotation speed.


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8. Periodical vibration

The duct is too small.

The system is not stable.

The duct vibrates with the pulsation of

the fan.

Redesign the duct.

Adjust the system.

Adjust the fan rotation

speed.9. Noise caused by

high-speed air running

through gaps and holesThe duct leaks air Apply gasket cement.

10. Clucks or squeaks

caused by obstructed

high-speed air

The duct has too sharp bends.

The duct flares sharply.

The duct tapers sharply.

The air speed in the duct is too high.

The damping adapter is too tight.

Redesign the duct.

Redesign the duct.

Redesign the duct.

Redesign the duct.

Adjust the damping

adapter.

The fan runs

normally but

the supplied

air volume is

deficient

1. Fan

The impeller is installed incorrectly.

The fan runs inversely.Contact the seller.

Adjust the phase

sequence of the power

supply.

2. Duct system

The actual duct system resistanceexceeds the designed resistance.

The duct is not hermetic.

The fire valve is closed.

Redesign the system.Apply gasket cement.

Open the fire valve.

3. FilterThe assembly is too dirty or even

blocked.Cleanse or replace the

filter.

4. Coil pipeThe assembly is too dirty or even

blocked.Rinse the coil pipe.

5. Short air

The outlet area is not sharply

separated from the inlet of the fan,

and the air runs through the partition

plate which provides poor partition to

the inlet area.

Apply a partition plate.

6.Blocked fan inlet

The elbow at the air return place is

too close to the unit.

The fan inlet is too close to the fan

panel.

Obstacles exist at the fan outlet.

Redesign the location of

the elbow.

Move the fan.

Remove the obstacles.

7. No straight pipe at the

fan outlet

A segment of straight pipe is set at

the fan outlet at the time of fan test.

If the straight pipe lacks in practical

use, the fan performance will be

deteriorated, and the fan rotation

speed may increase to overcome the

resistance caused by it.

Install a straight pipe.

8. Obstacles in the air

systemObstacles exist at the fan outlet.

A bend exists at the fan outlet.Remove the obstacles.

Redesign the duct.


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The fan runs

normally but

the supplied

air volume is

excessive

1. System

The fan size is improper.

The overhauling door is open.

The system is out of balance, and the

actual resistance is less than the

designed resistance.

No damper or damper vane is

installed.

The filter is detached.

Redesign the duct.

Close the overhauling

door

Redesign the system.

Install damper or damper

vane.

Reinstall the filter.

2. Duct The return duct leaks air. Apply gasket cement.The air in

the air

conditioner

room is not

fresh.

1. FilterThe filter is too dirty. Rinse or replace the

filter.

2. Fresh airThe fresh air volume is deficient. Increase fresh air.


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modular ahu manual

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