Installation and Operation Instructions Document 8001F

Installation and Operation

Instructions for

Mini-Combo II

TM

(Models MCT, MCS)

Residential Gas-Fired

Space/Water Heater

NOTE: This manual is to be used in conjunction with Document 1025, Installation and Operation

Instructions for Mini-Therm II JV boilers.

U.S. Trademark Reg. 2,094,168

China Trademark Reg. 988,311

FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician, qualified in hot water boiler installation and maintenance. Improper installation and/or operation could create carbon monoxide gas in flue gases which could cause serious injury, property damage, or death.

Improper installation and/or operation will void the warranty.

WARNING

If the information in this manual is not followed exactly, a fire or explosion may result causing property damage, personal injury or loss of life.

Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.

WHAT TO DO IF YOU SMELL GAS

• Do not try to light any appliance.

• Do not touch any electrical switch; do not use any phone in your building.

• Immediately call your gas supplier from a nearby phone. Follow the gas supplier's instructions.

• If you cannot reach your gas supplier, call the fire department.

Installation and service must be performed by a qualified installer, service agency, or gas supplier.

AVERTISSEMENT

Assurez-vous de bien suivres les instructions données dans cette notice pour réduire au minimum le risque d’incendie ou d’explosion ou pour éviter tout dommage matériel, toute blessure ou la mort.

Ne pas entreposer ni utiliser d’essence ni d’autres vapeurs ou liquides inflammables dans le voisinage de cet appareil ou de tout autre appareil.

QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ:

• Ne pas tenter d’allumer d’appareils.

• Ne touchez à aucun interrupteur. Ne pas vous servir des téléphones dansle bâtiment où vous vous trouvez.

• Appelez immédiatement votre fournisseur de gaz depuis un voisin. Suivez les instructions du fournisseur.

• Si vous ne pouvez rejoindre le fournisseur de gaz, appelez le sservice des incendies.

L’installation et l’entretien doivent être assurés par un installateur ou un service d’entretien qualifié ou par le fournisseur de gaz.

A subsidiary of BRADFORD WHITE Corporation

Page 2

LAARS Heating Systems

TABLE OF CONTENTS

SECTION 1.

General Information

1.1

Introduction ....................................................... 3

SECTION 2.

Installation

2.1

2.2

2.3

2.4

2.5

Location ............................................................ 3

Heater Placement ............................................. 3

Piping ............................................................... 5

Wiring ............................. 5, 6, 7, 8, 9, 10, 11, 12

Sequence of Operation .................................. 13

SECTION 3.

Replacement Parts

3.1

3.2

Ordering Information ...................................... 15

Parts List ........................................................ 15

Mini-Combo II

Page 3

SECTION 1.

General Information

WARNING

This manual supplies information on the application, installation and operation of the indirect water heater unit. A complete instruction manual of the operation of the hydronic boiler (Document 1025) is supplied along with this manual. Both manuals should be reviewed completely before proceeding with the installation.

• Failure to follow the instructions provided may result in personal injury, death or substantial property damage.

• Any modifications to the boiler, water tank, gas and water connections, or wiring may void warranty.

• Consult the factory or local factory representative with any questions or problems regarding this equipment.

AVERTISSEMENT

Ce manuel donne des renseignements sur l’application, l’installation et le fonctionnement du chauffe-eau indirect. Un manuel complet d’instruction sur le fonctionnement de la chaudière hydronique

(Document 1025) est fourni avec ce manuel. Les deux manuels doivent être examinés attentivement avant de procéder à l’installation.

• Si les instructions ne sont pas suivies, il peut en résulter des blessures personnelles, la mort ou des dégâts matériels substantiels.

• Toute modification apportée à la chaudière, au réservoir d’eau, aux branchements de gaz et d’eau ou aux fils électriques peut invalider la garantie.

• Consultez le représentant de l’usine principale ou locale pour toute question ou problème concernant ce matériel.

1.1 Hazards and Your Safety

- Hot Water Can Scald!

The Consumer Product Safety Commission (CPSC) and some states/provinces recommend a temperature setting of 130°F (54°C) or less. The water heater thermostat is factory set to approximately 120°F (49°C).

If thermostat will be set above factory setting, install an anti-scald valve at either the water heater or at each hot water faucet.

• Tempering valves are not anti-scald valves since they do not have a positive shutoff in case cold water supply fails. They are not recommended for shower/tub service. If needed, install an anti-scald valve at each shower/tub.

• Water heated to a temperature suitable for clothes washing, dish washing and other sanitizing needs can scald and cause permanent injury.

• Children and elderly, infirmed, or physically handicapped persons are more likely to be injured by hot water. Never leave them unattended in a bathtub or shower. Never allow small children to use a hot water tap or draw their own bath. If anyone using hot water in the building fits this description, or if state/province laws or local codes require certain water temperature at hot water taps, take special precautions:

Install an anti-scald valve at water heater or at each hot water faucet, bath, and shower outlet.

Use lowest practical temperature setting.

• Studies have indicated that dangerous bacteria can form in potable water distribution system if certain minimum water temperatures are not maintained.

Contact local health department for more information.

SECTION 2.

Installation

This installation must conform with the instructions in this manual and, where applicable:

National Fuel Gas Code (ANSI Z223.1).

National Electric Code (NEC-NFPA 70).

Local, state, provincial, and national codes, laws, regulations and ordinances.

In Canada - Natural Gas and Propane Installation

Code, CSA B149.1 and the Canadian Electric Code

(CEC - Can/CSA C22.1.

Where the recommendations made in this manual differ from local or national codes, the local or national codes take precedence.

2.1 Location

This water heater/boiler unit is not intended for outdoor installation. Select a convenient location where water leakage from the tank or connections will not result in damage to areas adjacent to the appliance or to lower floors of the structure. When a safe location cannot be found, install a suitable drain pan under the appliance, and pipe it to an adequate drain.

2.2 Heater Placement

The heater must be placed to provide clearances on all sides for maintenance and inspection. Allow 4 inches

(102mm) on each side for piping access. There must also be minimum distances maintained from combustible surfaces. Figure 2 shows minimum clearance from combustible surfaces. The Mini-Combo unit can be installed in a closet, as long as the minimum clearances are maintained. Special attention should be paid to the air supply opening to the closet. Refer to Table 1.

Page 4

LAARS Heating Systems

B

C

Vent Damper*

Mini-Therm

Boiler

(50-125)

Tank

Relief Valve

A

CL

System

Check Valve

Check Valve

24 1 /

2

622

(Sizes 50 & 25)

25 635

(Size 75 &

100)

FRONT VIEW

54

1372

Tank

Aquastat

Drain

Valve

24

610

7

178

28

711

Boiler

MC A B C In/Out

Size inches mm inches mm inches mm

NPT

50 58¾ 1492 12½ 318

75 58¾ 1492 12½ 318

100 59¾ 1518 14¼ 362

4

5

5

102

127

127

1¼

1¼

1¼

125 59¾ 1518 14¼ 362 6

152

*Vent damper is optional on some Canadian units.

1¼

Figure 1. Dimensional Information.

Gas

NPT

½

½

½

½

SIDE VIEW

Mounted

Pump

Hot

Water

Tank

Outlet

31

787

24

610

Dimensions shown in inches mm.

7

178

Inlet

24

610

Domestic

Approx.

Inlet/Outlet Weight

NPT lbs.

kgs

¾

¾

258 117

274 124

¾

¾

280 127

286 130

Minimum clearances from combustible surfaces: left side right side rear front top in.

mm

2

0

51

0

6

152

4

102

23

584

Service clearances: allow 4 102 on each side for piping access.

Space Heating -

Refer to Document 1025

6 152

2

51

24

610

28

711

4 102

23 584

Hot

Water

Supply

Cold

Water

Supply

Figure 3. Piping Schematic.

Top Clearance

Figure 2. Closet Installation.

Dimensions shown in inches

mm.

Figure 4. Typical Expansion Tank Installation.

Mini-Combo II

Page 5

Model

Net Free Area - square inches sq. mm

Inside Air Outside Air

MC50

MC75

MC100

MC125

100 645

100 645

100 645

125 807

15 97

20 129

25 161

32 207

Area indicated is for one of two openings: One at floor level and one at the ceiling, so the total free area would be double the figures indicated. Refer to Document 1025 for more information

Table 1. Minimum Recommended Air Supply.

2.3 Piping

• To Prevent damage to the unit, all soldering is to be done prior to assembling the cold and hot water, and any other connections to the tank.

• Use suitable pipe dope or tape.

• Before piping the boiler to the heating system, be sure to install the system check valve (provided with the unit) onto the inlet (return) tee of the boiler with arrow pointed downward (see

Figure 3).

• If anti-freeze is used in boiler system, local codes may require a backflow preventer on cold supply line. Use anti-freeze specifically intended for hydronic heating system. Inhibited propylene glycol is recommended.

WARNING

Do not use automotive or ethylene glycol anti-freeze, or any undiluted anti-freeze. This can cause severe personal injury, death or substantial property damage.

AVERTISSEMENT

N’utilisez pas d’antigel de moteur ou à base d’éthylène glycol ou toute sorte d’antigel dilué. Il peut en résulter des blessures personnelles, la mort ou des dégâts matériels substantiels.

If a backflow preventer, pressure reducing valve or check valve is in cold water supply, install an expansion tank on cold water supply line (Figure 4) to prevent normal thermal expansion from repeatedly forcing open the Temperature and Pressure (T&P) relief valve.

T&P relief valves discharge piping must be directed so that hot water flows away from all persons. Attach run-off tube to T&P valve and run tube within 6"

(152mm) from floor. No reducing couplings, valves, or any other type of restriction is to be installed in this line.

This run-off tube must be installed to allow free and complete drainage of both valve and run-off tube.

Filling Storage Water Tank

1.

Open hot water faucet in house to allow air in the tank and in piping to escape.

2.

Open shut-off valve(s) in cold water supply line.

3.

Open shut-off valve(s) in hot water supply line.

4.

When water discharges from the faucet, close it.

Check for system leaks and repair if necessary.

Filling and connecting boiler pipes:

Consult the JV boiler manual, Document 1025.

CAUTION

Never use water heater/boiler unless it is completely filled with water.

ATTENTION

N’utilisez jamais le chauffe-eau/chaudière s’il n’est pas complètement rempli d’eau.

2.4 Wiring

Priority System: Under this wiring the storage tank will be supplied before space heating. This will insure that it gets adequate hot water flow from the boiler to maintain a fully rated delivery of domestic hot water.

CAUTION

In this priority mode, any demand for space heating is postponed until the storage water tank has reached set temperature. This delay in supplying the space heating zones is usually not noticed by the inhabitants of the living spaces. However, in the event of certain storage water tank malfunctions, space heating could be delayed indefinitely. If undetected and uncorrected, freezing damage to piping could result.

ATTENTION

Dans ce mode de priorité, toute demande de chauffage est retardée jusqu’à ce que le reservoir à eau ait atteint la température pré-réglée. Ce retard n’est normalement pas ressentie pas les habitants des zones habitables. Cependant, dans le cas d’un mauvais fonctionnement du réservoir d’eau, le chauffage pourrait être retardé indéfiniment. Si ce problème n’est pas détecté et corrigé, la tuyauterie pourrait geler.

WARNING

Electrical shock can cause severe personal injury or death. Disconnect power supply to the boiler before doing any electrical work.

AVERTISSEMENT

Les chocs électriques peuvent causer des blessures corporelles graves voire la mort. Débranchez la chaudière avant de commencer les travaux d’électricité.

Page 6

Electrical Connection: (See Figure 5, 6 and 7)

1.

Remove the two screws attaching the front cover of the control box.

2.

There are five wires coiled in the area on the right side of the control box, supplied with wire nuts: 2 black wires twisted together, 2 white wires twisted together, and a brown wire.

3.

Follow Figures 5, 6 and 7. Remove the wire nut from the two black wires, and connect the hot lead from a 115 volt power supply to both wires. Secure the three wires with the wire nut.

4.

The two white, neutral wires should be joined to the other neutral lead coming from the 115 volt power supply, and the neutral lead coming from the pump

(space heating).

5.

The brown wire attaches to the hot side of the space heating pump.

6.

There is a molex connector located on the left side of the control panel. Connect the vent damper harness to the molex connector and the other end to the vent damper receptacle.

NOTE: The connection in step 6 should remain intact at all times, otherwise the boiler will not fire.

Some Canadian units are supplied with vent damper jumper plug. Do not remove jumper unless vent damper is to be installed.

LAARS Heating Systems

Mini-Combo II

Page 7

OPTIONAL

AQUASTAT

WALL

THERMOSTAT

(FIELD

SUPPLIED)

R

R

BR

P

HIGH

LIMIT

O

24V

COM

SEN

VENT DAMPER

RECEPTACLE*

P

R

Y

TANK

AQUASTAT

R

Y

Y

TRANSFORMER

24V 115V

W

BK

G

ZONE

PUMP

RELAY

Y

BK

BR

BL

TERMINAL

STRIP

P

JUMPER

Y

POWER VENTER

FAN PROVING

SWITCH

RECEPTACLE

SEE DOC. 1056

BK - BLACK

W

- WHITE

R

- RED

Y

- YELLOW

BL - BLUE

BR - BROWN

O

- ORANGE

P

- PURPLE

G

- GREEN

SENSOR

SPARK IGNITION WIRE

115V-FACTORY WIRED

115V-FIELD WIRED

24V-FACTORY WIRED

24V-FIELD WIRED

IF ANY OF THE ORIGINAL WIRE (AS

SUPPLIED WITH THE APPLIANCE) MUST

BE REPLACED, IT MUST BE REPLACED

WITH APPLIANCE WIRING MATERIAL

SUITABLE FOR 105 DEGREES C OR ITS

EQUIVALENT

BK

BK

BLOCKED

VENT

SAFETY

SWITCH

Y

ROLL-OUT

BL

SAFETY SWITCH

BR

TH

Y

TR

BL

R R

TANK

PUMP

RELAY

BR

BK

PILOT BURNER &

THERMOCOUPLE

HOT

115/60HZ

POWER SUPPLY

NEUTRAL

GROUNDING

CONDUCTOR

PUMP

(FIELD

SUPPLIED)

W

W

Y

TANK

PUMP

THE BOILER WILL NOT OPERATE WITHOUT

THE AUTOMATIC VENT DAMPER. THE VENT

DAMPER WIRE HARNESS MUST BE

INSERTED INTO THE VENT DAMPER

RECEPTACLE

* IN CANADA: SOME UNITS ARE SUPPLIED

WITH VENT DAMPER JUMPER PLUG. DO

NOT REMOVE JUMPER UNLESS VENT

DAMPER IS TO BE INSTALLED.

MODEL MCT

H2001700H

GAS VALVE

HW VR8300

Figure 5. Wiring Diagram, Model MCT.

Page 8

LAARS Heating Systems

Figure 6. Wiring Diagram, Model MCS, Sizes 50-75.

Mini-Combo II

Page 9

Figure 7. Wiring Diagram, Model MCS, Sizes 100-125.

Page 10

LAARS Heating Systems

*

Figure 8. MCT Schematic.

*Some Canadian units are supplied with vent damper jumper plug. Do not remove jumper unless vent damper is to be installed.

Mini-Combo II

Page 11

Figure 9. MCS Schematic, Sizes 50-75.

Page 12

LAARS Heating Systems

*

*Some Canadian units are supplied with vent damper jumper plug. Do not remove jumper unless vent damper is to be installed.

Figure 10. MCS Schematic, Sizes 100-125.

Mini-Combo II

2.5 Sequence of Operation

115 Volts Supply

Transformer

Vent Damper Motor

Tank Stat

(common)

Domestic Demand

(N.C.)

Tank Pump

(energized)

High Limit

Switch

Vent Damper

Open

Power Vent

Fan Switch (optional)

Safety Limit

Switches

Main Gas Valve

(energized)

Boiler On

Figure 11. Sequence of Operation.

Heating Demand

(N.O.)

Heating Pump

(energized)

Page 13

Page 14

LAARS Heating Systems

Figure 12. Parts Identification.

Mini-Combo II

Page 15

SECTION 3.

Replacement Parts

3.1 Ordering Information

To order or purchase parts for the Laars products, contact your nearest Laars dealer or distributor. If they cannot supply you with what you need, contact Laars Customer Service at the address shown on the back cover of this manual.

Visit our website at www.laars.com for Service Center listings

3.2 Parts List

14

15

16

17

18

9

10

11

12

13

6

7

4

5

8

#

1

2

3

4

1

1

1

1

2

1

4

2

1

1

1

1

1

1

Qty Part #

1

Description

20085700 Weldment, Panel, Base

1

1

20085600 Weldment, Panel, Top

20086300 Weldment, Panel, Door

20086400 Panel, Side, Right

20127900 Weldment, Panel, Side, Left

20085900 Panel, Rear

20086500 Panel, Access

20084000 Bracket, Mounting, Left

20085400 Bracket, Support, Tank

P2015400 Tee, Blk, 1¼" x 1¼" x ¾" NPT

P0014400 Nipple, Black, ¾" NPT x 2.5" LG

P0014100 Nipple, Close, ¾" NPT

P2016900 Elbow, Blk, 90°, ¾" x 1" NPT

P0009300 Elbow, Street, Blk, ¾" NPT

H2078100 Label, Attention, Toxicity

P2014800 Fitting, Compress,

7

/

8

" OD x ¾" NPT

P0008300 Elbow, Blk, 90°, ¾" NPT

A2085600 Valve, Check, ¾" NPT

19 6 ft.

P2015000 Tubing, Copper, Type “L”

7

/

8

" OD

20 1 A2085700 Valve, Drain, Tank, ¾" NPT

21

22

23

1

1

1

P0025300 Nipple, Brass, ¾" NPT x 2" LG

E0205000 Temperature Control, Electronic

A2085400 Valve, Relief, Temp & Pressure

24

25

26

27

2

1

1

1

2

A2085300 30 Gal Water Tank, Single Wall HX

A2085301 30 Gal Water Tank, Double Wall HX

Field Supplied Nipple, Brass ¾" NPT x 4" LG

Field Supplied Nipple, Brass 1" NPT x 3" LG

20087300 Door Latch Assembly

28

29

1

1

H2020600 Logo, Mini-Como II

H2016800 Label, Warning, Installation

33

36

37

38

39

#

30

31

32

40

41

42

43

45

2

1

1

1

2

1

1

1

1

1

Qty Part #

2

Description

H0090700 Label, Hot

56 not shown part not sold

F0024300 Screw, 10-16 x

5

/

8

" LG

S0064900 Bushing, Nylon, Univ,

7

/

8

" Dia.

A0066500 Pump, circulator, 1/25 HP

P0017100 Nipple, Close, Blk, 1¼" NPT

A2086600 Valve, Check, 1¼" NPT

H2017100 Tag, Important, Check Valve

A2087600 Handle, Door

H2017800 Label, Caution, Setting, Temp

A2086700 Flange, Pump, ¾" NPT

Vendor Supplied Well, Immersion, ¾ NPT

F0035900 Screw, #6-32 x

5

/

8

" LG,

46

47

48

49

1

1

1

1

Phillips, Rnd Hd

Vendor Supplied Nipple, Brass 1" NPT x 2" Long

P0095000 Tee, 1" x 1" x ¾", Black Iron

P0071400 Plug, 1" Stainless Steel w/Vibroseal

20084001 Bracket, Mounting, Right

50

51

52

53

1

1

1

2

A2001500 Pump, Taco, 220V

E2103100 Sensor, Temperature

Q0068400 Tubing, Aluminum, 5"

F0035600 Nut, Speed, Push On

54 4¼ ft E0020900 Conduit, Flex,

3

/

8

"

60

61

62

55

56

2

2

E0008300 Nut, Conduit, Lock

E0008100 Conduit Connector,

3

/

8

"

57 5 E0007700 Wire Nut, 2 #4 Wires

58 4½ ft E0052500 Wire, #18 AWG

3

/

64

", Yellow

59 4½ ft E0051900 Wire, #18 AWG

3

/

64

", White

2

1

1

E0036100 Bushing

E0088400 Relay

E0097700 Relay, Case and Cover

A subsidiary of BRADFORD WHITE Corporation

800.900.9276 • Fax 800.559.1583 (Customer Service, Service Advisors)

20 Industrial Way, Rochester, NH 03867 • 603.335.6300 • Fax 603.335.3355

1869 Sismet Road, Mississauga, Ontario, Canada L4W 1W8 • 905.238.0100 • Fax 905.366.0130

www.Laars.com

Litho in U.S.A. © Laars Heating Systems 0806 Document 8001F