Yazaki CH-K30 User manual

GAS-FIRED DOUBLE-EFFECT

ABSORPTION CHILLER-HEATER

This product is a gas-fired absorption unit which provides chilled water for cooling or

hot water for heating in central plant type air conditioning systems. Units with nominal

refrigeration capacities of 30, 40, 50, 60, 80, and 100 tons are complete with operating

and safety controls.

When this equipment is correctly applied, installed in accordance with Yazaki

INSTALLATION INSTRUCTIONS, and properly maintained, it can provide many years

of trouble-free operation.

CONTENTS

GENERAL Page

ABSORPTION PRINCIPLE 2

COOLING OPERATION 2

HEATING OPERATION 3

CONTROLS

GENERAL INFORMATION 4

CONTROL ADJUSTMENTS 6

OPERATION

COOLING 7

HEATING 7

SAFETY CONTROLS 7

REMOTE CONTROL 7

PRECAUTIONS 7

MAINTENANCE Page

GENERAL INFORMATION 8

ROUTINE MAINTENANCE 8

MAINTENANCE INTERVALS 8

EVACUATION OVERVIEW 8

CHEMICAL MAINTENANCE 9

WINTER SHUTDOWN 10

TROUBLESHOOTING 10

WATER QUALITY 11

ERROR CODES 11

STARTUP & MAINTENANCE

DATA SHEET 13

WARRANTY

YAZAKI LIMITED EXPRESS

WARRANTY 14

OPERATING INSTRUCTIONS

CH-K30, 40, 50, 60, 80, 100

GENERAL

These instructions are intended to

acquaint the Owner/End User with the

operation and general maintenance

requirements of Yazaki CH-K gas-fired

double-effect Absorption Chiller-Heaters.

Please read ALL instructions carefully and

observe precautions. Failure to operate and

maintain this equipment in accordance with

the OPERATING INSTRUCTIONS may

affect the equipment performance and

product Warranty.

If the equipment does not operate as

expected, check the Troubleshooting Guide

in these instructions BEFORE calling your

Yazaki Authorized Service Provider (ASP).

This approach will not only save cost but

also avoid any unnecessary downtime.

ABSORPTION PRINCIPLE

Yazaki absorption chiller-heaters use a

solution of lithium bromide and water, under

a vacuum, as the working fluid. Water is the

refrigerant and lithium bromide is the

absorbent.

During cooling operation, refrigerant

liquid boils under the influence of a deep

vacuum in the evaporator and creates a

refrigeration effect which removes heat from

the chilled water circuit.

The double-effect absorption cycle has

two generators, one heated by a burner and

the other heated by superheated refrigerant

vapor. It also utilizes a condenser, an

evaporator, and an absorber.

The absorber and condenser are water

cooled and heat is normally rejected to a

cooling tower, though ground loop is also an

option.

COOLING OPERATION

High Temperature Generator (HGE)

The gas burner heats a dilute lithium

bromide solution in the HE and the boiling

process drives superheated refrigerant vapor

and droplets of semi-concentrated solution

into the primary separator. The semi-

concentrated solution is precooled through a

heat exchanger before flowing into the LGE.

Low Temperature Generator (LGE)

Superheated refrigerant vapor from the

primary separator heats the semi-

concentrated solution in the LGE.

Refrigerant vapor that is liberated from this

solution flows into the Condenser while the

fully concentrated lithium bromide solution is

precooled through another heat exchanger

before flowing to the Absorber.

Condenser

In the condenser, refrigerant vapor is

condensed on the surface of the condenser

tubing bundle and latent heat, removed by

the cooling water, is rejected to a cooling

tower. Refrigerant liquid accumulates in the

condenser and then passes through an

orifice into the evaporator.

Evaporator

In the evaporator, refrigerant liquid is

exposed to a substantially deeper vacuum

than in the condenser due to the influence of

the absorber. As refrigerant liquid flows over

the surface of the evaporator tubing bundle,

it boils and removes from the chilled water

circuit an amount of heat equivalent to the

latent heat of the refrigerant. When at

design condition, the recirculating chilled

water is cooled to 44.6°F (7°C) while the

refrigerant vapor is attracted to the

concentrated solution dripping over the

absorber tubing bundle.

Absorber

A deep vacuum in the absorber is

maintained by the affinity of the concentrated

solution from the LGE for the refrigerant

vapor formed in the evaporator. Refrigerant

vapor is absorbed by the concentrated

lithium bromide solution flowing across the

surface of the absorber tube bundle. The

heat of condensation and dilution are

removed by the cooling water and rejected to

a cooling tower. The resulting dilute solution

is preheated through heat exchangers before

the solution pump returns it to the HGE

where the cycle is repeated.

Figure 1 –DOUBLE-EFFECT

ABSORPTION CYCLE (COOLING)

HEATING OPERATION

High Temperature Generator (HGE)

The solution boils in the HGE and

superheated refrigerant vapor and semi-

concentrated solution flow into the primary

separator in exactly the same manner as in

the cooling cycle.

Low Temperature Generator (LGE)

In Heat mode, the changeover valve

opens a path for the semi-concentrated

solution to flow out of the primary separator

directly into the Absorber/Evaporator sump.

Therefore, the LGE and both heat

exchangers are completely bypassed while

in Heat mode.

Condenser/Absorber

It is imperative that there be NO

COOLING WATER FLOW in the Heat mode.

As such, neither the Condenser nor the

Absorber have any function in Heat mode.

Evaporator

Since the Evaporator acts as the

Condenser in Heat mode, hot refrigerant

vapor condenses on the surface of the

evaporator coil and heat, equivalent to the

latent heat of the refrigerant, is transferred to

the hot water circuit, heating it to a leaving

temperature of 131°F (55°C). The condensed

refrigerant drips off the evaporator and into

the absorber sump where it mixes with the

semi-concentrated solution, diluting it once

again.

Figure 2 –DOUBLE-EFFECT

ABSORPTION CYCLE (HEATING)

CONTROLS

GENERAL INFORMATION

A control panel (Figure 3) is built into each

absorption chiller-heater and is located on

the control box, behind the hinged, lower

front-left panel. After inspecting the control

panel and/or making changes to the mode of

operation, make sure that the front panel

closed securely to prevent rain from entering

the cabinet as well as unauthorized

tampering with the controls.

The chiller-heater may also be supervised

and controlled by external control systems to

a limited degree when the necessary

interconnections are installed. Additional

controls and interlocks can be explained by

your ASP.

Once COOLING or HEATING operation is

selected and the unit is started, the chiller-

heater will function automatically and remain

in operation as long as there is a demand for

chilled or hot water.

Be aware that the STOP lamp is lit

anytime the unit is Disabled. The RUN lamp

is lit anytime the unit is Enabled, whether or

not the unit is actively running to control the

chilled or hot water temperature.

Figure 3 –CONTROL PANEL

Figure 4 –CONTROL BOX LAYOUT

Fuse Rating Chart

Symbol

Amps

Replacement

Bussmann Model

GLQ-3, GMQ-3 or

GMQ-3-2/10, Rated

300vac.

Fuji Model FGAO-2,

Rated 250vac.

F11, F12

Fuji Model FGAO-2,

Rated 250vac.

F31, F32

Fuji Model FGAO-2,

Rated 250vac.

FB11,

FB12

Fuji Model FGAO-2,

Rated 250vac.

FB21,

FB22

Nagasawa Model

GAB

Fuji Model FGAO-2,

Rated 250vac.

FT1, FT2,

FT3

Fuji Model FGAO-2,

Rated 250vac.

Figure 5 –FUSE PANEL

Unit Size

THRP Settings (amps)

208v

230v

K30

3.0

2.8

K40

4.5

4.0

K50

4.5

4.0

K60

6.0

5.5

K80

6.0

5.5

K100

6.0

5.5

Figure 6 –SOLUTION PUMP THERMAL OVERLOAD

CONTROL ADJUSTMENTS

The leaving chilled water temperature is

controlled to a standard rating point of

44.6°F (7°C). The operating dead band of

Low Fire is 3.6°F (2°C). The Low Fire dead

band is not adjustable. The operating dead

band of High fire is 7.2°F (4°C). The High

Fire dead band can be cut in half by setting

Dip Switch 2 on the I/O Board to ON. The

leaving chilled water temperature can be

adjusted using the TC potentiometer on the

CPU Board. The leaving chilled water set

point can be set in a range of 40.1°F (4.5°C)

to 59.9°F (15.5°C).

Similarly, the leaving hot water standard

rating point is 131°F (55°C). The Low Fire

dead band and High Fire dead bands are

identical to Cool mode, but the High Fire

dead band can be cut in half by setting Dip

Switch 4 on the I/O Board to ON. The

leaving hot water temperature can be

adjusted using the TH potentiometer on the

CPU Board. The leaving hot water set point

can be set in a range of 122.9°F (50.5°C) to

140.9°F (60.5°C).

Figure 7 –TEMPERATURE CONTROL ADJUSTMENTS

OPERATION

COOLING

To engage the unit in Cool mode, press

the COOL button on the Control Panel.

Then choose between RUN and REMOTE

setting. If the unit was not in Heat mode

prior to this point, and the unit is Enabled,

then the unit will engage in cool mode

immediately. If, however, the unit was

previously in Heat mode, the unit will engage

a 30-minute mode change timer and the

PRETIME light will illuminate. Once the 30-

minute timer has expired, the PRETIME light

will go out and the unit will engage Cool

mode immediately.

HEATING

To engage a chiller-heater in Heat mode,

press the HEAT button on the Control Panel.

Then choose between RUN and REMOTE

setting. If the unit was not in Cool mode

prior to this point, and the unit is Enabled,

the unit will engage in heat mode

immediately. If, however, the unit was

previously in Cool mode, the unit will engage

a 30-minute mode change timer and the

PRETIME light will illuminate. Once the 30-

minute timer has expired, the PRETIME light

will go out and the unit will engage Heat

mode immediately.

SAFETY CONTROLS

Safety and limit controls monitor critical

operating conditions within the chiller-heater

and will shut down the unit when abnormal

conditions arise. An Error Code that

designates the cause of the shutdown (see

Table 2) is displayed on the control panel.

When the abnormal condition has been

cleared, press the alarm RESET button to

restart the cooling or heating operation. If

Error Code 52 is amongst the codes being

displayed, it will also be necessary to press

the RESET button on the burner controller

itself. If the unit does not restart, then

contact your ASP.

REMOTE CONTROL

The chiller-heater can be Enabled or

Disabled remotely. It can also be instructed

to change between Cool and Heat modes

remotely. No other remote control capability

exists. To enable the unit to be controlled

remotely, switch the unit into REMOTE. The

unit will now Enable or Disable based on the

external connection signals tied into the

Junction Box.

If the unit is in RUN, the unit will ignore

Enable/Disable signals from the remote

signal source, but the unit will still follow

remote Cool/Heat changeover commands

while set to RUN.

PRECAUTIONS

1. Ensure that all AUTO-OFF-HAND

switches for external pumps and the

cooling tower fan are set in the AUTO

position during normal operation. The

chiller-heater is designed to automatically

control the chilled water pump, cooling

water pump, and cooling tower fan.

2. At the beginning of the cooling season

clean and refill the cooling tower with

fresh water.

3. During the winter season the cooling

tower and cooling water circuits should be

drained to avoid freezing and scaling in

the absorber and condenser circuits.

4. When two or more absorption chiller-

heater modules are installed in parallel,

set all units for the same operating mode.

Leaving water temperature set points may

differ, but operating mode must always be

the same.

MAINTENANCE

GENERAL INFORMATION

ALL MAINTENANCE SHOULD BE

PERFORMED BY TRAINED AND

EXPERIENCED PERSONNEL. Your Yazaki

Authorized Service Provider (ASP) can help

you establish a standard maintenance

procedure.

For your safety, keep the area around

the equipment clear and free of combustible

materials, gasoline and other flammable

substances. DO NOT obstruct service

access or combustion air supply to the

equipment.

ROUTINE MAINTENANCE

Routine maintenance should be provided

throughout the life of the equipment to

ensure satisfactory performance and

operation.

During the warranty period, an ASP must

be engaged to provide routine maintenance

on chiller-heaters at the beginning of each

cooling season. When the chiller-heater is

used for process cooling or heavy load

operation it may be necessary to schedule

additional service visits to evacuate non-

condensable gases from the vacuum

section.

MAINTENANCE INTERVALS

Every 4 months (Spring, Summer, Winter):

Evacuation (Units not used in Heat mode can

skip the winter evacuation)

Every 12 months:

Burner Combustion Analysis and Gas

Pressure Check (Supply and Manifold)

Inhibitor Check (If required. For the K-Series, an

inhibitor charge is needed every 3 years, on

average.)

Palladium Cell Heater Check

Flow Rate Check

Solution Pump Rotation Check

Flame Rod Replacement (if required)

Igniter Rod Replacement (if used and required)

Every 3 years:

HGE Inspection (pulling the burner to see the

condition inside the HGE)

Average interval for Inhibitor Charge

Average interval for Flame and Igniter Rod

Replacement.

EVACUATION OVERVIEW

Arguably the most important aspect of

maintenance for the chiller-heater is

maintaining a proper level of vacuum.

Evacuation is performed at the front of the

machine. The evacuation service valves are

referred to as Service Valve A (upper) and

Service Valve B (lower).

The evacuation service valves are back-

seating access valves similar to those used

throughout the refrigeration industry. The

stem has a 10mm square head. The stem

secures a copper seal to a steel seat inside

the valve. Do not over-torque this valve or

else the seal can become damaged and

compromise vacuum integrity. The proper

torque is 14.75 ft-lbs (20 Nm). Yazaki offers a

torque wrench (P/N N7510) specifically for

use with this service valve.

A number of precautions should be

observed at all times during evacuation.

*** Great care must be taken to ensure

that no oil enters the Yazaki chiller-

heater! Permanent damage could result

from even a small amount of oil being

introduced into the vacuum section! ***

Never leave a vacuum pump running

unattended. Power loss could allow the

chiller-heater vacuum section to suck oil

out of the pump in a matter of seconds.

Never have the Service Valve open

unless the vacuum pump is running and

the integrity of the vacuum lines between

the valve and the pump has been verified

as tight.

Never have the vacuum pump discharge

tube in the water bucket unless the

vacuum pump is running. The vacuum

pump could suck water from the bucket

and contaminate the oil charge.

Never pull an extended vacuum

(exceeding a few hours). If such seems to

be necessary, there is likely to be

something wrong with the vacuum pump

or the oil has been contaminated with

moisture inherently found inside the

chiller-heater vacuum section.

Always start with a fresh oil charge in the

vacuum pump.

Always use a liquid trap or collection

flask.

Always use a vacuum gauge to verify the

level of vacuum achieved. Run time has

almost nothing to do with the level of

vacuum achieved.

Use only dual-stage, deep vacuum

pumps. Typical refrigeration vacuum pumps

may not perform well on a vessel as large as

the chiller-heater’s vacuum section. Just

because the vacuum pump has stopped

producing bubbles in the water bucket does

NOT mean the vacuum level is adequate. A

digital vacuum gauge MUST be used in

order to determine the true level of vacuum

achieved.

The desired level of vacuum on a

machine that is not running would be less

than 2000 microns (<2 mmHg), with less than

1000 microns (<1 mmHg) preferred. On a

machine actively running in Cool mode

(currently attempting to satisfy chilled water loop

load), the desired level of vacuum is 4000-

5000 microns (4-5 mmHg), no less. Any lower

than that on a running machine can cause

the vacuum pump to remove an

extraordinary amount of refrigerant vapor

(water).

A step-by-step, detailed evacuation

method is provided in the Service Manual.

The general evacuation assembly setup is

displayed in Figure 9.

Figure 9 –GENERAL EVACUATION

ASSEMBLY SETUP

CHEMICAL MAINTENANCE

It is not necessary to perform regular

chemical maintenance on the Yazaki

chiller-heater itself.

The chemical balance has been

established in the factory during run testing.

Normally, the only chemical that must be

maintained is the inhibitor charge. By

capturing non-condensable gases,

comparisons can be made to determine if

the normal hydrogen byproduct is being

produced at anticipated rates. If more

hydrogen is being produced than anticipated,

a maintenance inhibitor charge may need to

be introduced into the machine by the ASP.

An inhibitor charge is typically needed every

three (3) years in Yazaki gas-fired chiller-

heaters.

SHUTDOWN

The fluids within the chiller-heater itself

need no preparation for freezing conditions.

Only the fluids in the chilled water and

cooling water circuits need to be addressed

during potentially freezing conditions.

When the equipment is located outdoors

in climates subject to freezing, cooling water

should be drained from the chiller-heater,

fluid circuit piping, and cooling tower at the

end of the cooling season. Use glycol of

adequate concentration in the chilled water

and heat medium circuits to prevent freeze

damage. The glycol will reduce the cooling

and heating capacity but this may be offset

somewhat by increasing the circuit fluid flow

rate. If in doubt about potential freeze

damage in your area, discuss it with your

ASP. Damage to the unit due to freezing is

not covered by the product warranty.

If a unit is to be shut down for the winter,

but no fluid circuits are to be drained, then

simply Disable the chiller-heater and allow

the unit to complete its Post Dilution Cycle.

Once completed, it is safe to leave the unit

as it sits for the off-season. Take

appropriate measures to ensure the fluids in

all fluid circuits are protected from freezing

(glycol, heat tape, etc.).

If a chiller-heater is to be shut down long-

term, then fluid circuits should be drained.

Disable the chiller-heater and allow the unit

to complete its Post Dilution Cycle. Once

completed, turn off the breaker on the unit

control panel. Then drain each fluid circuit.

Once drained, make sure to blow in both

directions through each circuit with

compressed air (or similar) to make sure no

significant amount of liquid remains inside

them. Close all isolation valves so as to

isolate the unit from the rest of the respective

fluid circuit. Pressurize each fluid circuit in

the chiller-heater with dry nitrogen to a

pressure of 1-2 PSI (7-14 kPa) to help inhibit

corrosion in the circuit during storage. It may

be desirable to break the vacuum in the

chiller-heater itself as well. If doing so,

pressurize the unit to the same pressure as

the circuits using nitrogen. See the Service

Manual for further details.

TROUBLESHOOTING

SYMPTOM: Chiller-heater does not operate.

Possible Cause

REMEDY

No High Voltage

Check the LED for the Power indication on the Control Panel. If it is not illuminated, check the

main power disconnect, fuses, and breakers.

Solution Pump Not

Running

Check the THRP overload switch. Check the GP temperature. Until the GP temperature rises

above 190°F (88°C), the solution pump may remain off until the GP temperature warms up.

Chiller-heater is not

running but WTO

temperature is above

set point.

Nothing may be wrong. If the system chilled water loop has satisfied by reaching the desired set

point, the unit will shut down until the WTO sensor reads a temperature 3.6°F (2°C) above the set

point temperature, no matter how long that may take. To force operation, turn off power to the

chiller-heater, leave power off for 10 seconds, and then restore power. The chiller-heater should

start up if the WTO sensor reading is above the set point.

SYMPTOM: Poor cooling capacity.

Possible Cause

REMEDY

Poor Vacuum

Evacuate the machine per normal maintenance procedure. A leak check may also be necessary.

High Inlet Cooling

Water Temperature

Check the cooling tower fan. Check the cooling tower fluid level.

Low Cooling Water

Flow Rate

Check the cooling tower sump and cooling water circuit strainers.

Condenser/Absorber

Fouling, Scale Buildup

Check the cooling water circuit strainers. A chemical de-scaling procedure will be necessary.

Everything appears

normal but the leaving

chilled water

temperature is too

high.

Nothing may be wrong. If the load of the chilled water circuit exceeds the capacity of the chiller-

heater, the system will find equilibrium at a higher leaving chilled water temperature. If the

temperature drop through the chilled water loop is approximately 8-12°F (4-6°C), then the unit

may actually be giving its full capacity and its capacity simply may not be enough. Check for

reasons that the load may have artificially increased (open doors, new equipment, leaking valves, etc.)

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