McQuay FMS Installation Manual

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Page 1

Installation & Maintenance Data IM 407-14

Vertical Water Source Heat Pump & Cooling Only Units

Group: WSHP Part Number: 106581201

Date: March 2002

Model nomenclature ............................................................ 2

Transportation and shortage ................................................ 2

Installation ....................................................................... 2–4

Electrical data ...................................................................... 5

Piping ............................................................................... 5,6

Cleaning and flushing system .............................................. 6

Start-up ........................................................................... 6, 7

Contents

Operating limits ................................................................... 7

Wiring diagrams ............................................................. 8–13

Unit operation .................................................................... 14

Thermostat Connections, Mark IV/AC units ....................... 15

Options for Mark IV/AC units ....................................... 16–20

Troubleshooting ................................................................. 21

Maintenance ...................................................................... 22

Page 2

Model Nomenclature

W FDD 1 009 E Z

Product Category

W = WSHP

Product Identifier

See box below

Design Series

1 = A Design 2 = B Deisgn 3 = C Design 4 = D Design 5 = E Design

Nominal Capacity

007 = 7,000 009 = 9,000 012 = 12,000 015 = 15,000 019 = 19,000 etc. . .

McQuay Product Identifiers

FDD = Floor Mtd/DDC Controls/Ext. Range/Less Board FDS = Floor Mtd/DDC Controls/Std. Range FDE = Floor Mtd/DDC Controls/Ext. Range FME = Floor Mtd/Mark IV/Ext. Range FDL = Floor Mtd/DDC Controls/Std. Range/Less Board FMS = Floor Mtd/Mark IV/Std. Range

Coil Options

(None)

Voltage

E= 208/230-60-1 F= 208/230-60-3 J= 265-60-1 K= 460-60-3 L= 575-60-3 M= 230-50-1 N= 380-50-3

Note: Installation and maintenance are to be performed only by qualified personnel who are familiar with local codes and regulations, and are experienced with this type of equipment. Caution: Sharp edges are a potential injury hazard. Avoid contact with them.

Transportation and Storage

Upon receipt of the equipment, check carton for visible damage. Make a notation on the shipper’s delivery ticket before signing. If there is any evidence of rough handling, the cartons should be opened at once to check for concealed damage. If any damage is found, notify the carrier within 48 hours to establish your claim and request their inspection and a report. The Warranty Claims Department should then be contacted.

Do not stand or transport the machines on end. For

storing, each carton is marked with “up” arrows.

In the event that elevator transfer makes upended posi-

tioning unavoidable, absolutely insure that the machine is in

the normal upright position for at least 24 hours before operating.

Temporary storage at the jobsite must be indoors, completely shielded from rain, snow, etc. High or low temperatures naturally associated with weather patterns will not harm the conditioners. Excessively high temperatures of

140

F (60oC) may deteriorate certain plastic materials and cause permanent damage. In addition, the solid-state circuit boards may experience operational problems.

Installation

General

1. To prevent damage, this equipment should not be operated for supplementary heating and cooling during the construction period.

2. Inspect the carton for any specific tagging numbers as requested by the installing contractor. At this time the voltage, phase and capacity should be checked against the plans.

3. Check the unit size against the plans to be sure that the unit will be installed in the correct location.

4. Before installation, check the available closet dimensions versus the dimensions of the unit.

5. Pay attention to the location and routing of water piping, and electrical wiring. The locations of these items are clearly marked on submittal drawings.

6. The installing contractor will find it beneficial to confer with piping, sheet metal, ceiling and electrical foremen together before installing any conditioners.

7. Remove shipping block from under the fan wheel.

8. We recommend that the contractor cover the conditioners with plastic film to protect the machines during finishing of the building. This is important if spraying fireproofing material on bar joists, sandblasting, spray painting and plastering operations have not been completed. If plastic film is not available, the shipping carton may be modified to cover the units during construction.

9. On extra-quiet construction units with spring mounted compressors, remove the shipping block under the compressor.

Page 2 / IM 407

Page 3

Unit location

1. Locate the unit in an area that allows for easy removal of the filter and access panels, and has enough space for service personnel to perform maintenance or repair. Provide sufficient room to make water, electrical and duct connections.

2. The contractor should make sure that access has been provided including clearance for duct collars and fittings at water and electrical connections.

3. Allow adequate room around the unit for a condensate trap.

4. The unit can be installed “free standing” in an equipment room; however, closet installations are more common for small vertical type units. Generally, the unit is located in the corner of a closet with the nonducted return air facing 90o to the door and the major access panels facing the door as in Figure 1A. Alternatively, the unit can have a ducted return air with the opening facing the door and the major access panels facing 90

Figure 1A. Typical closet installation with louver door return

to the door as in Figure 1B.

5. It is recommended that the unit be located on top of a vibration absorbing material such as rubber or carpet to reduce any vibration. See Figure 5.

6. If optional field installed controls are required (boilerless system), space must be provided for the enclosure to mount around the corner from the electrical entrances. Do not locate the side of the unit too close to a wall. See Figures 1A and 1B.

Minimum distance requirement from return air duct collar to wall, for non-ducted units.

Model Distance

007 – 012 .......................... 4 inches

015 – 019 .......................... 5 inches

024 – 030 .......................... 6 inches

036 – 042 .......................... 7 inches

048 – 060 .......................... 8 inches

Filter access

Each unit is shipped with a filter bracket for side filter removal.

Heat Pump

With Left-Hand

Return Air Arrangement

Return

Air

Opt. Controls

Elec. Entrance

Main Access Panel

Condensate

Water Supply

Water Return

Louvered Door

RisersReturn Air Thru

Figure 1B. Typical closet installation with ducted return

Heat Pump

Return

Duct &

Grille

With Left-Hand

Return Air Arrangement

Air

Opt. Controls

Elec. Entrance

Main Access Panel Main Access Panel

Heat Pump

With Right-Hand

Return Air Arrangement

Opt. Controls

Elec. Entrance

Main Access Panel

Condensate

Water Supply

Water Return

Return Air Thru Louvered Door

Heat Pump

With Right-Hand

Return Air Arrangement

Opt. Controls

Elec. Entrance

NOTE: Minimum distance

Return

requirement for non-ducted

Air

units. (see chart above)

Return

Air

Duct &

Grille

Condensate

Water Supply

Water Return

Condensate

Water Supply

Water Return

Risers

IM 407 / Page 3

Page 4

Ductwork and attenuation

Discharge ductwork is normally used with these conditioners. Return air ductwork may also be required, but will require field installation of a return air duct collar/2" (51mm) filter rack kit.

All ductwork should conform to industry standards of

good practice as described in ASHRAE Systems Guide.

The discharge duct system will normally consist of a flexible connector at the unit, a noninsulated transition piece to the full duct size, a short run of duct, an elbow without vanes, and a trunk duct teeing into a branch circuit with discharge diffusers as shown in Figure 2. The transition piece must not have an angle greater than 30 performance can result. Do not connect the full duct size to the unit without using a transition piece down to the size of the discharge collar on the unit. With metal duct material, the sides only of the elbow and entire branch duct should be internally lined with acoustic insulation for sound attenuation. Glass fiber duct board material is more absorbing and may permit omission of the flexible connector.

The ductwork should be laid out so that there is no line of sight between the conditioner discharge and the distribution diffusers.

Return air ducts can be brought in through a wall grille and then to the unit. The return duct system will normally consist of a flexible connector at the unit and a trunk duct to the return air grille. With metal duct material, the return air duct should be internally lined with acoustic insulation for sound attenuation. Glass fiber duct board material is more absorbing and may permit omission of the flexible connector.

Return air ductwork to the unit requires the optional return air duct collar/2" (51mm) filter rack kit. See Figure 3. The kit can be installed for face side or bottom filter removal. The flexible connector can then be attached to the 1" (25mm) duct collar.

Do not use sheet metal screws directly into the unit cabinet for connection of supply or return air ductwork, especially return air ductwork which can puncture the drain pan or the air coil.

or severe loss of air

Figure 2.

Trunk Duct

Square Elbow (Both Sides Internally Lined With Acoustic Insulation)

Branch Duct (Internally Lined)

Duct Transition

Canvas Collar

Discharge Collar (on Heat Pump)

Heat Pump

2 ft. x 2 ft Diffuser

Ventilation air

Outside air may be required for ventilation. The temperature of the ventilation air must be controlled so that mixture of outside air and return air entering the conditioner does not exceed application limits. It is also general practice to close off the ventilation air system during unoccupied periods (night setback).

The ventilation air system is generally a separate building subsystem with distribution ductwork. Simple introduction of the outside air into each return air plenum chamber reasonably close to the conditioner air inlet is not only adequate, but recommended. Do not duct outside air directly to the conditioner inlet. Provide sufficient distance for thorough mixing of outside and return air. See “Operating limits” on page 7.

Figure 3.

Sizes 007 thru 042 Sizes 048 & 060

Page 4 / IM 407

Page 5

Electrical Data

General

1. Be sure the available power is the same voltage and phase as that shown on the unit serial plate. Line and low voltage wiring must be done in accordance with local codes or the National Electrical Code, whichever is applicable.

2. Apply correct line voltage to the unit. A 7⁄8" (22mm) or 11⁄8" (29mm) hole is supplied on the side of the unit. A disconnect switch near the unit is required by code. Power to the unit must be sized correctly and have time delay (dual element) fuses or an HACR circuit breaker for branch circuit overcurrent protection. See the nameplate for correct ratings.

230 Volt operation and 50 cycle units

All 208-230 volt single and three-phase units are factory wired for 208 volt operation. For 230 volt operation, the line voltage tap on the 24 volt transformer must be changed.

Figure 4A. Figure 4B.

Disconnect and cap the red lead wire and interchange it with the orange lead wire on the primary of the 24 volt transformer. Three-phase 50 cycle units require a neutral wire for 230/50/1 power.

Fan speed change

All units have two-speed fan motors and are shipped for high speed operation. On unit sizes 007, 009 and 012, the change from high speed to low speed is done by removing the black wire from the fan relay and connecting the red wire to the fan relay (Figure 4A). On units sizes 015 through 060, each fan motor is supplied with a 5-pin terminal block mounted on the fan motor. To change from high speed to low speed, move the wire from the black #3 location to the red #4 location on unit sizes 015 through 042 or to the red #5 location on units sizes 048 and 060. On 575 volt units, add a jumper between black #3 and blue #4 for low speed operation. See Figure 4B.

COMMON (WHITE)

FAN

MOTOR

BROWN (CAPACITOR) BLACK (HIGH SPEED)

RED (LOW SPEED)

Piping

1. All units are recommended to be connected to supply and return piping in a two-pipe reverse return configuration. A reverse return system is inherently self-balancing and requires only trim balancing where multiple quantities of units with different flow and pressure drop characteristics are connected to the same loop. A simple way to check for proper water balance is to take a differential temperature reading across the water connections. To insure proper water flow, the differential should be 10

A direct return system may also be made to work acceptably, but proper water flow balancing is more difficult to achieve and maintain.

2. The piping can be steel, copper or PVC.

3. Supply and return runouts are usually connected to the unit by short lengths of high pressure flexible hose which are sound attenuators for both unit operating noise and hydraulic pumping noise. One end of the hose should have a swivel fitting to facilitate removal for service. Hard piping can also be brought directly to the unit although it is not recommended since no vibration or noise attenuation can be accomplished. The hard piping must have unions to facilitate unit removal. See Figure 5 for typical piping setup.

4. Supply and return shutoff valves are required at each conditioner. The return valve is used for balancing and should have a “memory stop” so that it can always be closed off but can only be reopened to the proper

F (5oC) to 14oF (8oC).

COMMON CAPACITOR

HIGH SPEED LOW SPEED

LOW SPEED

FAN

MOTOR

YELLOW 1

BROWN 2

BLACK 3

*RED 4 *RED 5

*On unit sizes 048 and 060, terminal 4 is colorcoded blue and terminal 5 is color-coded red.

JUMPER

position for the flow required.

5. No unit should be connected to the supply and return piping until the water system has been cleaned and flushed completely. After the cleaning and flushing has taken place, the initial connection should have all valves wide open in preparation for water system flushing.

6. Condensate piping can be steel, copper or PVC. Each unit is supplied with a

⁄8" (22mm) ODM copper stub.

7. The condensate disposal piping must have a trap and the piping must be pitched away from the unit not less

⁄4" inch per foot (21mm per meter). Generally, the

than condensate trap is made of copper and soldered on the unit. See Figure 6. A piece of vinyl hose from the trap to the drain line is used for simple removal. A complete copper or PVC condensate system can also be used. Union fittings in the copper lines should be applied to facilitate removal. Factory supplied condensate hose assemblies have a

⁄8" (22mm) sweat to FPT fitting to facilitate connection of a flexible vinyl, rubber or steel braided hose.

8. No point in the drain system may be above the drain connection of any unit.

9. Automatic flow controlled devices must not be installed prior to system cleaning and flushing.

10. A high point of the piping system must be vented.

11. Check local code for the need for dielectric fittings.

IM 407 / Page 5

Page 6

Figure 5. Figure 6.

Balancing Blower Motor Access

Flexible Hose With Brass Pipe Fitting

Electrical & Compressor Access

Isolator Pad

Note: Condensate drain connection must be minimum of 1" (25mm) below connection to heat pump.

Note: Do not overtorque fittings. The maximum torque without damage to fittings is 30 foot pounds. If a torque wrench is not available, use as a rule of thumb, finger-tight plus one quarter turn. Use two wrenches to tighten the union, one to hold the line and one for simultaneous tightening of the nut.

Valve With

Close-off

Supply

Return

Condensate

(38mm)

⁄2"

Electrical Access Panel

⁄2"

(38mm)

Optional Cleanout

⁄4'' Per Foot

(21mm Per Meter)

Cleaning and Flushing System

1. Prior to first operation of any conditioner, the water circulating system must be cleaned and flushed of all construction dirt and debris.

If the conditioners are equipped with water shutoff valves, either electric or pressure operated, the supply and return runouts must be connected together at each conditioner location. This will prevent the introduction of dirt into the unit. Additionally, pressure operated valves only open when the compressor is operating.

Figure 7.

Return Runout

Supply Runout

Mains

Rubber Hose

Runouts Initially Connected Together

2. The system should be filled at the city water makeup connection with all air vents open. After filling, vents should be closed.

The contractor should start main circulator with pressure reducing valve makeup open. Vents should be checked in sequence to bleed off any trapped air to assure circulation through all components of the system.

Power to the heat rejector unit should be off, and the supplementary heat control set at 80

F (27oC).

While circulating water, the contractor should check

and repair any leaks in the piping. Drains at the lowest point(s) in the system should be opened for initial flush and blow-down, making sure city water fill valves are set to make up water at the same rate. Check the pressure gauge at pump suction and manually adjust the makeup to hold the same positive steady pressure both before and after opening the drain valves. Flush should continue for at least two hours, or longer if required, to see clear, clean drain water.

3. Supplemental heater and circulator pump should be shut off. All drains and vents should be opened to completely drain down the system. Short circuited supply and return runouts should now be connected to the conditioner supply and return connections. Teflon tape is recommended over pipe dope for pipe thread connections. Use no sealers at the swivel flare connections of hoses.

4. Trisodium phosphate was formerly recommended as a cleaning agent during flushing. However, many states and localities ban the introduction of phosphates into their sewage systems. The current recommendation is to simply flush longer with warm 80

F (27oC) water.

5. Refill the system with clean water. Test the litmus paper for acidity, and treat as required to leave the water slightly alkaline (pH 7.5 to 8.5). The specified percentage of antifreeze may also be added at this time. Use commercial grade antifreeze designed for HVAC systems only. Do not use automotive grade antifreeze.

6. Set the system control and alarm panel heat add setpoint

to 70

F (21oC) and the heat rejection setpoint to 85oF

C). Supply power to all motors and start the circulating

(29 pumps. After full flow has been established through all components including the heat rejector (regardless of season) and air vented and loop temperatures stabilized, each of the conditioners will be ready for check, test and start-up and for air and water balancing.

Start-up

1. Open all valves to full open position and turn on power to the conditioners.

2. Set thermostat for “Fan Only” operation by selecting “Off” at the system switch and “On” at the fan switch. If “Auto” fan operation were selected, the fan would cycle with the compressor. Check for proper air delivery.

Page 6 / IM 407

3. All units have two-speed motors. Reconnect for low speed operation if necessary.

4. Set thermostat to “Cool.” If the thermostat is an automatic changeover type, simply set the cooling temperature to the coolest position. On manual changeover types additionally select “Cool” at the system switch.

Page 7

Again, many conditioners have time delays which protect the compressor against short cycling. After a few minutes of operation, check the discharge grilles for cool air delivery. Measure the temperature difference between entering and leaving water. It should be approximately 1 temperature difference. For example, if the cooling temperature difference is 15 ture difference should have been 12

Without automatic flow control valves, a cooling temperature difference of 10

⁄2 times greater than the heating mode

F (8oC), the heating tempera-

F (5oC).

F to 14oF (5oC to 8oC) is about right. Adjust the combination shutoff/balancing valve in the return line to a water flow rate which will result in the 10

F to 14oF (5oC to 8oC) difference.

5. Set thermostat to “Heat.” If thermostat is the automatic changeover type, set system switch to the “Auto” position and depress the heat setting to the warmest selection. Some conditioners have built-in time delays which prevent the compressor from immediately starting. With most control schemes, the fan will start immediately. After a few minutes of compressor operation, check for warm air delivery at discharge grille. If this is a “cold building” start-up, leave unit running until return air to the unit is at least 65

F (18oC).

Measure the temperature difference between entering and leaving air and entering and leaving water. With entering water of 60 water should be 6

F to 80oF (16oC to 27oC), leaving

F to 12oF (3.3oC to 6.7oC) cooler, and

the air temperature rise through the machine should not

exceed 35oF (19oC). If the air temperature exceeds 35oF

(19

C), the airflow rate is probably inadequate.

If the water temperature difference is less than 6

(3.3

C), the water flow rate is excessive. If the water

temperature difference exceeds 12

F (6.7oC), then the

water flow rate is inadequate.

6. Check the elevation and cleanliness of the condensate line. If the air is too dry for sufficient dehumidification, slowly pour enough water into the condensate pan to ensure proper drainage.

7. If the conditioner does not operate, the following points should be checked: a. Is proper voltage being supplied to the machine? b. Is the proper type of thermostat being used? c. Is the wiring to the thermostat correct?

8. If the conditioner operates but stops after a brief period, check for: a. Is there proper airflow? Check for dirty filter, incorrect

fan rotation (3-phase fan motors only), or incorrect ductwork.

b. Is there proper water flow rate within temperature

limits? Check water balancing; backflush unit if dirt clogged.

9. Check the unit for vibrating refrigerant piping, fan wheels, etc.

10. Do not lubricate the fan motor during the first year of operation as it is prelubricated at the factory.

Operating Limits

Environment

This equipment is designed for indoor installation only. Sheltered locations such as attics, garages, etc., generally will not provide sufficient protection against extremes in temperature and/or humidity, and equipment performance, reliability, and service life may be adversely affected.

Power supply

A voltage variation of ±10% of nameplate utilization voltage is acceptable. Three-phase system unbalance shall not exceed 2%.

Operating voltages

115/60/1............................... 104 volts min.; 127 volts max.

208-230/60/1 .......................197 volts min.; 253 volts max.

265/60/1............................... 238 volts min.; 292 volts max.

230/50/1............................... 197 volts min.; 253 volts max.

460/60/3............................... 414 volts min.; 506 volts max.

380/50/3............................... 342 volts min.; 418 volts max.

575/60/3............................... 515 volts min.; 632 volts max.

Note: Voltages listed are to show voltage range. However, units operating with overvoltage and undervoltage for extended periods of time will experience premature component failure.

Additional information

1. Standard units — Units are designed to start and operate

in an ambient of 40 with entering water at 70 at the flow rates used in the ARI Standard 320-86 rating test, for initial start-up in winter.

Note: This is not a normal or continuous operating con-

dition. It is assumed that such a start-up is for the purpose of bringing the building space up to occupancy temperature.

F (5oC), with entering air at 40oF (5oC),

F (21oC), with both air and water

2. Extended range units — Extended range heat pump

conditioners are designed to start and operate in an ambient of 40 entering water at 40

F (5oC), with entering air at 40oF (5oC), with

F (5oC), with both air and water at the flow rates used in the ARI Standard 320-86 rating test, for initial start-up in winter.

Note: This is not a normal or continuous operating con-

dition. It is assumed that such a start-up is for the purpose of bringing the building space up to occupancy temperature.

Air and water limits

STANDARD EXTENDED

UNITS RANGE UNITS

Cooling Heating Cooling Heating Min. Amb. Air 50oF/10oC50oF/10oC40oF/5oC40oF/5oC Normal Amb. Air 80oF/27oC70oF/21oC80oF/27oC70oF/21oC Max. Amb. Air 100oF/38oC85oF/29oC 100oF/38oC85oF/29oC Min. Ent. Air ➀ ➁ 50oF/10oC50oF/10oC50oF/10oC40oF/5oC Normal Ent. Air, 80/67 db/wb 27/19oC21oC 27/19oC21oC Max. Ent. Air, 100/83 db/wb ➀ ➁ 38/28oC27oC 38/28oC27oC

F70oF 80/67oF70oF

F80oF 100/83oF80oF

Water enthalpy

Min. Ent. Water

➀ ➁

Normal Ent. Water 85oF/29oC70oF/21oC85oF/29oC70oF/21oC Max. Ent. Air,

➀ ➁

➀ At ARI flow rate ➁ Maximum and minimum values may not be combined. If one value is at

maximum or minimum, the other two conditions may not exceed the normal condition for standard units. Extended range units may combine any two maximum or minimum conditions, but not more than two, with all other conditions being normal conditions.

Cooling Heating Cooling Heating

F/13oC55oF/13oC40oF/5oC40oF/5oC

F/43oC90oF/32oC 110oF/43oC90oF/32oC

110

IM 407 / Page 7

Page 8

60 Cycle Wiring Diagrams — Mark IV/AC Units

Figure 8. Unit sizes 007 through 012 (208-230, 265 volts, single-phase) 060686404 Rev. A

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

2. Unit is factory wired for 230V operation. If 230V power supply is used, transformer must be rewired by disconnecting the power from the red transformer primary wire and connecting the power lead to the orange transformer primary wire. Place an insulation cap on the red transformer primary wire.

3. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

4. All temperature and pressure switches are normally closed.

5. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

Figure 9. Unit size 015 (208-230, 265 volts, single-phase) 060856804 Rev. A

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

3. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

4. All temperature and pressure switches are normally closed.

5. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

Page 8 / IM 407

Page 9

Figure 10. Unit sizes 019 through 048 (208-230, 265 volts, single-phase) 060686606 Rev. C

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

3. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

4. All temperature and pressure switches are normally closed.

5. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

Figure 11. Unit sizes 060 (208-230 volts, single-phase) 063393303 Rev. C

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

3. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

4. All temperature and pressure switches are normally closed.

5. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

IM 407 / Page 9

Page 10

Figure 12. Unit sizes 024 through 060 (208-230 volts, three-phase) 060686704 Rev. B

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

3. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

4. All temperature and pressure switches are normally closed.

5. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

Figure 13. Unit sizes 024 through 060 (460 and 575 volts, three-phase) 060686804 Rev. B

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

2. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

3. All temperature and pressure switches are normally closed.

4. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

Page 10 / IM 407

Page 11

50 Cycle Wiring Diagrams — Mark IV/AC Units

Figure 14. Unit sizes 007 through 012 (230 volts, single-phase) 061415316 Rev. A

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

2. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

3. All temperature and pressure switches are normally closed.

4. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

Figure 15. Unit sizes 015 through 019 (230 volts, single-phase) 061415318 Rev. A

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

2. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

3. All temperature and pressure switches are normally closed.

4. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

IM 407 / Page 11

Page 12

Figure 16. Unit sizes 024 (230 volts, single-phase) 061415320 Rev. A

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

2. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

3. All temperature and pressure switches are normally closed.

4. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

Figure 17. Unit sizes 048 and 060 (230 volts, single-phase) 063393303 Rev. C

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

2. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

3. All temperature and pressure switches are normally closed.

4. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

Page 12 / IM 407

Page 13

Figure 18. Unit sizes 024 through 042 (380 volts, three-phase) 061415321 Rev. A

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

2. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

3. All temperature and pressure switches are normally closed.

4. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

Figure 19. Unit sizes 048 and 060 (380 volts, three-phase) 061415322 Rev. A

Notes:

1. Mark IV/AC controller board contains a static sensitive microprocessor. Proper grounding of field service personnel is required or damage to controller may result.

2. Terminal block on Mark IV/AC board provides 24 VAC at terminals R and C. All other terminals are 24 VDC output.

3. All temperature and pressure switches are normally closed.

4. Field supplied relays attached to the 24 volt terminals R, W, Y or G may introduce electrical noise. Never install relays in series with the inputs.

IM 407 / Page 13

Page 14

Unit Operation

General

Each unit has a printed circuit board control system. The low voltage output from the low voltage terminal strip on the control board is always 24 volts DC (direct current). Terminals R and C on the low voltage terminal strip supply 24 volts AC power. The unit has been designed for operation with a 24 volt mercury bulb type wall thermostat or a microelectronic wall thermostat selected by the manufacturer. Do not operate the unit with any other type of wall thermostat.

Two types of units are available: electromechanical control units or Mark IV/AC control units. Both have 24 volt DC circuits on the output of the low voltage terminal strip. Each requires its own unique automatic changeover thermostat.

Mark IV/AC control units

The Mark IV/AC circuit board is an optional control system with built-in features such as random start, compressor time delay, night setback, load shed, shutdown, condensate overflow protection, defrost cycle, brownout, and LED/fault outputs. Figure 28 shows the LED and fault output sequences.

The 24 volt low voltage terminal strip is set up so R-G energizes the fan, R-Y1 energizes the compressor for cooling operation, R-W1 energizes the compressor and reversing valve for heating operation. The reversing valve is set up to be energized in the heating mode. The circuit board has a fan interlock circuit to energize the fan whenever the compressor is on if the thermostat logic fails to do so.

The Mark IV/AC control board has a lockout circuit to stop compressor operation if any one of its safety switches opens (high pressure switch and low pressure switch on unit sizes 048 and 060). If the low temperature switch opens, the unit will go into the cooling mode for 60 seconds to defrost any slush in the water-to-refrigerant heat exchanger. After 60 seconds the compressor is locked out. If the condensate sensor detects a filled drain pan, the compressor operation will be suspended only in the cooling mode. The unit is reset by opening and closing the disconnect switch on the main power supply to the unit in the event the unit compressor operation has been suspended due to low temperature (freezestat) switch, high pressure switch, or low pressure switch on unit sizes 048 and 060. The unit does not have to be reset on a condensate overflow detection.

The Mark IV/AC control circuit has a fault output signal to an LED on a wall thermostat. Figure 28 shows for which functions the fault output is “on” (sending a signal to the LED).

The Mark IV/AC control circuit has built-in night setback operation. A “grounded” signal to the “U” terminal on the low voltage terminal strip puts the unit into the unoccupied mode for night setback operation. The fan shuts off and the unit is put under control from the night setback terminal on the thermostat, W2; day heating and cooling operation is locked out. R-W2 energizes the compressor and reversing valve for

Figure 28.

INDICATION

Normal mode Off On Off Off High pressure fault Off Off Flash On

* Low temperature fault Flash Off Off On

Condensate overflow On Dim Off On Brownout Off Flash Off On Load shed Off Off On Off Unoccupied mode On On Off Off Unit shutdown Off Flash Off On

YELLOW GREEN RED OUTPUT

LEDS FAULT

* In heating mode only.

Figure 29.

Unit #1 Unit #2

Time Clock

To activate the unoccupied mode for units on the same clock schedule, a single wire can be “daisy-chained” between units and simply grounded through the time clock contacts. The same system can also be done to activate the load shed and emergency shutdown modes by running additional wires between units to ground.

Unit #3

Ground

To Additional Units

heating operation. Night setback operation can be overridden for two hours by toggling the fan switch (intermittently closing the R to O terminals) on the Deluxe Auto Changeover thermostat. Day thermostat setpoints the control the heating and cooling operation. The Mark IV/AC control system is also set up for load shed and shutdown operation on receipt of a “grounded” signal to the “L” and “E” terminals, respectively, on the low voltage terminal strip. See Figure 29.

The P and C terminals of the Mark IV/AC board are used for pump restart. These terminals pass a voltage signal whenever the unit compressor is turned on. This signal is detected by a pump restart relay board providing an N.O. or N.C. set of contacts for heat pump loop circulation pump control. When used with the Loop Water Controller, the relay operation accommodates turning off circulation pump control. When used with the Loop Water Controller, the relay operation accommodates turning off circulation pumps during unoccupied periods with a safety override dependent on, at minimum, one WSHP's need. The P and C terminals may be “daisy-chained” between 200 units. See page 19.

Page 14 / IM 407

Page 15

Mark IV/AC Sequence of Operation

14-Position Terminal Strip

Pin Designation Description

1CTransformer ground (Ovac) 2RTransformer supply (24vac) 3V-DC power connection 4PPump request output 5A Alarm fault output 6UUnoccupied input 7LLoad shed input 8ERemote shutdown input

9F+DC power connection 10 Y1 Occupied cooling mode input 11 W1 Occupied heating mode input 12 G Fan only input 13 W2 Unoccupied heating mode

input

14 O Tenant override input

LED Status and Fault Output Status

Board Status LED’s Fault Output

Mode Yellow Green Red Terminal A

Occupied Off On Off Energized Unoccupied On On Off Energized Load Shed Off Off On Energized Condensate Overflow On Dim Off De-Energized High/Low Pressure Fault Off Off Flash De-Energized Low Temperature Fault* Flash Off Off De-Energized Brownout Off Flash Off De-Energized Emergency Shutdown Off Flash Off De-Energized

*in heating mode only Note: The fault output is energized when no faults exist. The fault output is

de-energized during faults and when unit power is off.

General Use and Information

The Mark IV/AC control board is provided with three drive terminals, R(24vac), F(24vdc), and C(Ovac) that can be used by the end user to drive the thermostat inputs (G, Y1, W1, and W2) and control inputs (U, L, E, and O). Any combination of a single board drive terminal (R, F, or C) may be used to operate the Mark IV/AC boards control or thermostat inputs. However, only one drive terminal (R, F, or C) can be connected to any individual input terminal or damage will occur. Some of the control inputs are used within the Water Source Heat Pump and not accessible to the end user. For example, HP, LT, and COF are not available for use by the end user.

Typically the Mark IV/AC board’s R(24vac) terminal is used to drive the board’s thermostat inputs and control inputs by connecting it to the R terminal of an industry standard thermostat. The control outputs of the standard thermostat are then connected to the Mark IV/AC board thermostat inputs and control inputs as needed. Any remaining board input(s) may be operated by additional thermostat outputs or remote relays (dry contacts only).

All Mark IV/AC board inputs must be operated by dry contacts powered by the control board’s power terminals. No solid state devices (Triacs) may be used to operate Mark IV/AC board inputs. No outside power sources may be used to operate Mark IV/AC board inputs.

Using Drive Using Drive Using Drive

Terminal R (24vac) Terminal F (vdc) Terminal C (ground)

De-energized Energized De-energized Energized De-energized Energized

Place the Meters

Red (+) Lead on

Input to be

checked

U, L, E, Y1, W1,

G, W2, O 14vac 26vac

• Do I need to use the same drive terminal for all Mark IV/AC board inputs?

Place the Meters Place the Meters Place the Meters

on Black (-) Lead Black (-) Lead Black (-) Lead

on C on V on R

10 to 22 to

30 to 10 to 22 to

0vdc

33vdc

14vac 26vac

Yes

Flash Green LED

Flash Yellow L E D

Turn On Red LED

Turn On Yellow LED

Reversing Valve On

Read Outputs

Check Timers

Pres. Sw ?

Brown Out ?

Low Temp Sw ?

Lo Shed ?

N S B ?

Cond. Overflow?

R - W 1 ?

R -Y 1 ?

Stop Comp.

Flash Red LED

Stop Comp.

Stop Fan

Stop Comp.

Htg Mode?

Stop Comp.

R - W 2 ?

Start Comp.

Cooling Mode

Stop Comp.

Time Delay

Start Comp.

Yes

IM 407 / Page 15

Page 16

Thermostat Connection Diagrams

Mark IV/AC Units – Unit Sizes 007 to 060

Manual Changeover Thermostat (P/N 106069001)

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

P/N 106069001 Includes Thermostat and Subbase

GWYR

Thermostat Terminals

Standard Automatic and Manual Changeover Thermostat (P/N 105570701)

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

(Honeywell P/N T834C2416) Fan Switch: Auto / On System Switch: Heat / Off / Cool

GW1Y1A Rc Rh

Thermostat Terminals

P/N 105570701 Includes Thermostat and Subbase (Honeywell P/N’s T874A1598 and Q674E1460) Fan Switch: Auto / On System Switch: Off / Heat / Auto / Cool

Deluxe Automatic Changeover Thermostat (P/N 105571001)

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

OW2GW1Y1 A R

Thermostat Terminals

Note: Thermostat provides a fixed 13oF differential between W1 and W2.

P/N 105571003 Includes Thermostat and Subbase (Honeywell P/N’s T874C1869 and Q674C1579) Fan Switch: Auto / On / Tenant Override System Switch: Off / Auto

Time Clock (by others)

Daisy-chain connection to additional units Mark IV/AC board “U” terminals

Non-Programmable Electronic Thermostat (P/N 105570801)

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

Operation: The units Mark IV/AC board will be in the occupied mode, monitoring terminals W1 and Y1 and ignoring terminal W2, when the time clock contacts are open. The Mark IV/AC board will be in the unoccupied mode, monitoring terminal W2 and ignoring terminals W1 and Y1, when the time clock contacts are closed. No cooling is allowed during the unoccupied mode. The tenant override feature of the thermostat allows the occupant to force a 2-hour override of unoccupied mode. During this override period the W1 and Y1 terminals are monitored and the W2 terminal is ignored (same as occupied).

Page 16 / IM 407

GW1Y1 RRc C

Thermostat Terminals

P/N 105570801 Includes Thermostat and Wall Plate (Honeywell P/N T8524D1064)

Page 17

Programmable Electronic Thermostat (P/N 105570901)

WSHP Mark IV/AC Board Low Voltage Terminal

OW2GW1Y1 F E L U A P V R C

P/N 105570901 Includes Thermostat and Wall Plate

GW1Y1 RRc C

Thermostat Terminals

(Honeywell P/N T8624D2111)

Multiple Unit Control Panel for Mark IV

Up to 3 Units (Part No. 056794201)

The multiple unit control board is an accessory used when you need to control up to 3-units from a single thermostat. The board is typically mounted in the unit control box closest to the thermostat. A maximum of 2 boards may be used together if up to 6-units must be connected and controlled from a single thermostat.

This version of the board uses VAC relays and should not be used in combination with any other accessories or equipment that require VDC connections to the "G", "W1", or "Y1" terminals (i.e. Boilerless System Kit).

The multiple unit control board provides the components necessary to protect the Mark IV/AC board from electrical damage that may occur when using standard off-the-shelf relays.

Multiple Unit

Control Panel

GWY R C

GW1Y1RRc C

Thermostat Terminals

TB4

TB3

TB2

TB1

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

Y G W

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

Y G W

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

Y G W

Up to 2 Units (Part No. 106059801)

The multiple unit control board is an accessory used when you need to control up to 2-units from a single thermostat. The board is typically mounted in the unit control box closest to the thermostat. The "G", "W", "Y", "C", and "L" connections are short flying leads pre-attached to the board. A maximum of 3 boards may be used together if up to 4-units must be connected and controlled from a single thermostat.

This version of the board uses VDC relays and should not be used in combination with any other accessories or equipment that require VAC Connections to the "G", "W1" or "Y1" terminals (i.e. Boilerless System Kit). Do not use the unoccupied (U-terminal) feature with the multiple unit control board.

The multiple unit control board provides the components necessary to protect the Mark IV/AC board from electrical damage that may occur when using standard off-the-shelf relays.

Multiple Unit

Control

Panel

GWY C L

GW1Y1 R Rc C

Thermostat Terminals

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

Y G W

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

IM 407 / Page 17

Page 18

Motorized Valve & Relay for Unit Sizes 007 to 060

Wired as shown below the motorized valve will open on a call for compressor operation. Valves for unit sizes 007 to 019 are 1⁄2˝ power-open spring-return while unit sizes 024 to 060 are 3⁄4˝ power-open power-close. Other thermostat combinations may be used. Valve and auxiliary relay are purchased separately.

Note: The wiring shown below can only be used when the “P” terminal is not being used as a pump restart signal to other equipment. If the “P” terminal must be used as a pump restart signal to other equipment, then wire the auxiliary relay’s yellow wire to “Y1”, white wire to “W1”, and orange wire to “C”, then the valve will open on a call for occupied

heating or cooling from the thermostat.

WSHP Mark IV/AC Board Low Voltage Terminal Strip

Valve

P/N 060977401 - 1/2" Valve Kit P/N 060977301 - 3/4" Valve Kit P/N 859004354 - Valve Relay Kit

Connector

36" (915 mm)

Lead Length

Anti-Short Bushing

Conduit

Pins,

Female

Black to 6

White to 1

3 1

Plug

2 3

Orange

Yellow

White

Auxiliary Relay

631

Note: Thermostat provides a fixed 13oF differential between W1 and W2.

Options on Mark IV/AC Units

Auxilliary Relay (P/N 106059701)

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

Operation: In this example the auxiliary relay contacts can be used to indicate a fault condition. With the auxiliary relay connected as shown, the normally open contacts will close during a fault condition.

2 3

Auxiliary Relay

Orange

Yellow

White

OW2GW1Y1 F E L U A P V R C

OW2GW1Y1 A R

Thermostat Terminals

P/N 105571003 Includes Thermostat and Subbase (Honeywell P/N’s T874C1869 and Q674C1579) Fan Switch: Auto / On / Tenant Override System Switch: Off / Auto

The auxiliary relay is designed to interface external equipment with the Mark IV/AC board. The auxiliary relay has been provided with the components necessary to protect from electrical damage that may occur to the Mark IV/AC board when using standard off-the-self relays. The auxiliary relay can be used to provide fault signals, unit operation signals, or to provide a means for remote equipment to control the Mark IV/AC board. The orange, yellow, and white connections are short flying leads pre-attached to the board. The diagrams shown are some connection examples.

Time Clock (by others)

Daisy-chain to additional Mark IV/AC board “U” terminals

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

Operation: In this example the auxiliary relay contacts can be used to signal WSHP fan operation to another device. In this example when the thermostat energizes the “G” terminal the auxiliary relay normally open contacts will close.

2 3

Auxiliary Relay

Orange

Yellow

White

Page 18 / IM 407

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

2 3

Auxiliary Relay

Orange

Yellow

White

Operation: In this example the auxiliary relay is used to interface other control devices to the Mark IV/AC board. Using the Orange (-) and White (+) wires, and 24vac or 24vdc, another device could be used to start and stop the WSHP heating sequence.

Page 19

6.5 (165 mm) (007 – 042)

4.12 (105 mm) (048 – 060)

Boilerless System Kit (BSK)

P/N 062522201 for Sizes 007 to 042 P/N 062522204 for Sizes 048 to 060

The BSK option for use with the Mark IV/AC control board provides the capability to control a remote duct heater. The duct heater must be provided with a low voltage control circuit that only requires a set of dry contacts for operation.

The contacts shown on the Boilerless System board (termi-

9.66

(245 mm)

(007 – 042)

14.50

(368 mm)

(048 – 060)

1.75

(44.5 mm)

Wire Ends to be Field

Connected to the

Mark IV/AC Board

nals 1, 2, and 3) are used to control the remote duct heater, the N.O. contacts will close on a call for duct heater heat. POT1 provides a means to manually adjust the water temperature setpoint (adjustment range is 43 Normal/Override switch provides a means to manually force electric heat to always be used in place of heat pump heat when in the override position (default position is normal - heat pump heat).

When the water temperature drops below the value of POT1, then the duct heater will be used instead of heat pump heat on a call for heat from the low voltage thermostat (not included).

43 Ohm

2 3

Auxiliary Relay

WSHP Mark IV/AC Board Low Voltage Terminal Strip

4-pin

Plug

GR GR

Orange

Yellow

White

RD WH

Boilerless

System

Board

Normal

Pot 1

Override

F to 60OF). The

Water

Temperature

Sensor

12345

Signal to remote duct heater control circuit

The BSK field installed kits include the sheet metal enclosure with cover, wire harness, boilerless system board, auxiliary relay, and water temperature sensor. When used, one BSK is required for each unit. To use the BSK kit you attach the sheet metal enclosure to the unit as shown, route the 4-wire harness through knockouts and connect to the Mark IV/AC board, mount and connect and insulate the water temperature sensor on the water supply line, and then connect the duct heater control contacts to the duct heater control circuit.

Wire ends

from

Boilerless

System Kit

WSHP Mark IV/AC Board

Low Voltage Terminal Strip

OR BR RD

43 Ohm

0W2 GW1Y1 F E L U A P VR C 0W2 G W1Y1FE L U A P V R C

GW1Y1 W2 Y2 R Rc C

Thermostat Terminals

If night setback (U-terminal) is used, the duct heater will respond to the occupied W1 thermostat signal. The load shed input (L-terminal) cannot be used for other control functions when being used with the BSK.

The BSK is a DC voltage device, when the BSK is used the thermostat must be wired for VDC operation, one example is provided below. This example is for a 2-circuit WSHP, R1 is a field supplied 24vdc relay. R1 is not required on 1-circuit units.

WSHP Mark IV/AC Board

Low Voltage Terminal Strip

IM 407 / Page 19

Page 20

Pump Restart Relay Kit P/N 061419001

Used as an option with the Mark IV/AC board, the pump restart relay kit provides a means to alert the loop water controller that water flow is required by a WSHP so that the system pump can be started. This option is typically used in installations where the pump may be shut off when there is no need for water flow (i.e. temperature OK, etc.). Typically only one pump restart relay kit is required per installation as up to 200 Mark IV/AC boards can be “daisy-chained” together.

The Mark IV/AC “P” terminal is used to determine WSHP compressor operation. Wired as shown below, when compressor operation is required, the Mark IV/AC “P” terminal

will change state causing a contact closure between terminal 58 and 64 signaling the loop water control (LWC) panel to restart the loop pump if Off.

The pump restart relay kit is typically mounted within one WSHP or within the LWC panel, whichever is more convenient, diagrams are provided below for each location. To install the relay, remove the cover on the double-faced tape provided on the relay and attach the relay either to the inside of the LWC panel (adjacent to circuit breaker CB1 and terminal block TB3) or in the WSHP control box (in a convenient location), then wire as shown below.

Wiring Pump Restart Relay when Installed within the LWC Panel

WSHP Mark IV/AC Board Low Voltage Terminal Strip

OW2GW1Y1 F E L U A P V R C

Pump

Restart

Relay

7 6 5 4 3

64 58

Daisy chain to other Mark IV/AC board “P” and “C” terminals

Loop

Water Controller Terminals

2 1

Wiring Pump Restart Relay when Installed within a WSHP Control Box

WSHP Mark IV/AC Board Low Voltage Terminal Strip (Circuit 1)

OW2GW1Y1 F E L U A P V R C

Daisy chain to other Mark IV/AC board “P” and “C” terminals

64 58

Controller Terminals

Loop

Water

Pump

Restart

Relay

7 6 5 4 3 2 1

Page 20 / IM 407

Page 21

WARNING

Troubleshooting Water Source Heat Pump

To avoid electrical shock, personal injury or death, be sure that field wiring complies with local and national fire, safety, and electrical codes, and voltage to the system is within the limits shown in the job-specific drawings and unit electrical data plate(s). Power supply to unit must be disconnected when making field connections. To avoid electrical shock, personal injury or death, be sure to rigorously adhere to field wiring procedures regarding proper lockout and tagout of components.

Low Voltage, check power supply voltage

Check wiring - loose or broken and check for bad connection

Check relays and contacts, also capacitor and wiring

Check high pressure switch and low temperature switch to see if unit is cycling on the safety

Check to see if the reversing valve is not hung up and is operating correctly

Check condensate overflow switch in cool mode of operation

Fuse may be blown, circuit breaker is open

Fan, nor Compressor Run

Compressor runs in short cycle

Compressor attempts to start but doesn’t

Wires may be loose or broken. Replace or retighten wires

Fan operates,

Unit

Insufficient cooling or heating

Compressor does not

Unit Control, check thermostat for correct wiring or bad t’stat

Check capacitor

Check wiring - loose or broken and check for bad connection

Hi pressure lockout A. Cool mode, check water flow B. Heating mode, check air flow C. Check reversing valve for proper valve position

Check compressor overload make sure it’s closed

Check compressor to ground, or for internal short to ground.

Compressor winding may be open. Check continuity with ohm meter

Check compressor wiring for defective wiring or loose connection

Check for defective compressor internal windings with ohm meter

Check for bad compressor capacitor

Check for lock rotor amp draw

Check themostat for improper location

Check for proper air flow. Filter could be dirty

Check blower assembly for dirt or bad fan motor capacity

Check for low refrigerant charge

Check amp draw on blower assembly

IM 407 / Page 21

Page 22

Maintenance

1. Normal maintenance on all conditioners is generally limited to filter changes. Lubrication of the fan motor is not required but may be performed to extend motor life. Use SAE-20 nondetergent electric motor oil.

2. Filter changes are required at regular intervals. The time period between changes will depend upon the project requirements. Some applications such as motels produce a lot of lint from carpeting and linen changes, and will require more frequent filter changes. It is suggested that the filter be checked at 60-day intervals for the first year until experience is acquired. If light cannot be seen through the filter when held up to sunlight or a bright light, it should be changed. A more critical standard may be desirable.

3. The condensate drain pan should be checked annually and cleaned and flushed as required.

4. Recording of performance measurements of volts, amps, and water temperature differences (both heating and cooling) is recommended. A comparison of logged data with start-up and other annual data is useful as an indicator of general equipment condition.

5. Periodic lockouts always are caused by air or water problems. The lockout (shutdown) of the conditioner is a normal protective result. Check for dirt in the water system, water flow rates, water temperatures, airflow rates (filter may be dirty), and air temperatures. If the lockout occurs in the morning following a return from night setback, entering air below machine limits may be the cause.

Page 22 / IM 407

Page 23

Notes

IM 407 / Page 23

Page 24

This document contains the most current product information as of this printing. For the most up-to-date product information, please go to www.mcquay.com.