Thermo Products COMBOMAX User Manual

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COMBOMAX

Electricboiler withintegratedinstantaneouswaterheater

Models from 8 kW to 24 kW :

240 Volts ( single phase )

Use and Care Manual

With installation instructions for the contractor

Your COMBOMAX® electric boiler has been carefully assembled and factory tested to provide years of trouble-free service. This manual contains instructions for the safe and proper installation, operation and maintenance of the boiler, in order to ensure your full satisfaction

It is imperative that all persons who are expected to install, operate or adjust this boiler read the instructions carefully.

Any questions regarding the operation, maintenance, service or warranty of this water heater should be directed to the dealer or distributor you purchased it from. When all installation steps have been completed, replace this installation manual in its original envelope, and keep in a safe place near the heater for future reference.

THERMO 2000 INC.	revised : January 2006
Printed in Canada

Section 1 : Technical specifications

Table 1: Boiler specifications 240 Vac (single phase) :


	Power		Nominal load in amps		Numberof elements	\
	Power		Nominal load in amps			Stages\ Thermostats	pilots
Model			elements	circulator		Stages\ Thermostats	pilots	Wire	Fuse
				Including				Wire	Fuse
			Heating					Cu	Amps
	Kw	BTU/h	Heating					Cu	Amps
	Kw	BTU/h		the

COMBOMAX XX-8	8	27 296	33.3	34.3	1 X 3KW	2		8	50
COMBOMAX XX-8	8	27 296	33.3	34.3	1 X 5KW	2		8	50
					1 X 5KW
COMBOMAX XX-10	10	34 120	41.6	42.6	2 X 5KW	2		6	60
COMBOMAX XX-15	15	51 180	62.5	63.5	2 X 3KW	4		3	100
COMBOMAX XX-15	15	51 180	62.5	63.5	2 X 4.5KW	4		3	100
					2 X 4.5KW
COMBOMAX XX-18	18	61 416	75.0	76.0	4 X 4.5KW	4		3	100
COMBOMAX XX-20	20	68 240	83.4	84.4	4 X 5KW	4		2	125
COMBOMAX XX-24	24	81 888	100.0	101.0	4 X 6KW	4		1	125

Table 2 : Boiler and connection dimensions


Model	Capacity	Utility	Boiler	Height	Diam.	Ship.
		connection	connection			weight
Combomax 23	30 Gal US	3/4 ’’ Sweat F	1’’ NPT F	49’’	18’’	265 lbs
Combomax 34	40 Gal US	3/4 ’’ Sweat F	1’’ NPT F	65’’	18’’	315 lbs
Combomax 44	52 Gal US	3/4 ’’ Sweat F	1’’ NPT F	55’’	22’’	345 lbs
Combomax 64	76 Gal US	3/4 ’’ Sweat F	1’’ NPT F	67’’	24’’	425 lbs

Table 3 : Domestic hot water production capacity in US gallons


Model		1st hour		Continuous
	110F	140F	180F	110F		140F		180F
COMBOMAX 23-8	75	44	28	47	33		24
COMBOMAX 23-10	87	52	33	59	41		29
COMBOMAX 23-15	116	73	48	88	62		44
COMBOMAX 23-18	134	85	57	106	74		53
COMBOMAX 23-20	145	93	63	117	82		59
COMBOMAX 23-24	169	110	75	141	99		71


Model		1st hour		Continuous
	110F	140F	180F	110F		140F		180F
COMBOMAX 44-8	97	53	31	47		33		24
COMBOMAX 44-10	109	61	36	59		41		29
COMBOMAX 44-15	138	82	51	88		62		44
COMBOMAX 44-18	156	94	60	106		74		53
COMBOMAX 44-20	167	102	66	117		82		59
COMBOMAX 44-24	191	119	78	141		99		71


Model		1st hour		Continuous
	110F	140F	180F	110F	140F	180F
COMBOMAX 34-8	85	48	29	47	33	24
COMBOMAX 34-10	97	56	34	59	41	29
COMBOMAX 34-15	126	77	49	88	62	44
COMBOMAX 34-18	144	89	58	106	74	53
COMBOMAX 34-20	155	97	64	117	82	59
COMBOMAX 34-24	179	114	76	141	99	71



Model		1st hour		Continuous
	110F	140F	180F	110F	140F	180F
COMBOMAX 64-8	121	63	34	47	33	24
COMBOMAX 64-10	133	71	39	59	41	29
COMBOMAX 64-15	162	92	54	88	62	44
COMBOMAX 64-18	180	104	63	106	74	53
COMBOMAX 64-20	191	112	69	117	82	59
COMBOMAX 64-24	215	129	81	141	99	71

With domestic cold water at 40°F and heating water at 180°F

Operating temperature : from 50°F to 190°F; Maximum operating pressure: 30 psi

COMBOMAXMC Electric boiler Set-up, use and care guide (revised January 2006), Page 2.

DESSIN D'ATELIER / GENERAL DIMENSIONS COMBOMAX XX-XX				THERMO 2000 inc.
Figure 2		Legeng/Légende:
		1)	Boiler Water Supply Connection /
		2)	Alimentation du chauffage (1" npt F)
			Boiler Water Return/
		3)	Retour du chauffage (1" npt F)
			Domestic Water inlet /
7		4)	Entrée eau domestique (3/4" Sweat F)
			Domestic Water outlet/
		5)	Sortie eau domestique (3/4" Sweat F)
			Safety relief valve/
		6)	Soupape de sûreté (3/4" npt M.)
H	I		Temperature and pressure Gage/
			Indicateur de Température et pression (1/2'' npt. M)
		7) Drain Valve/
		8)	Valve de drainage (3/4'' npt F)
			Power supply wiring/
		9)	Alimentation électrique
F 1			Pilot Lights/
			Lampe témoin
		10) Electrical Compartments/
			Compartiment électrique
4		11) Circulator wiring/
			Alimentation pompe
		12) Thermostat wiring/
			Connection thermostat
		13) Air vent/
G			Purgeur d'air
		14) Valve 3 voies/
			3 ways valve
		15) Valve thermostatique/
			Thermostatic mixing valve
		16) Adjustable leg/
			Patte de support
14	15	3		6
				13	5	8

C E

DIMENSION/ DIMENSIONAL

Modèle/

Model

in.

degrés/degree

COMBOMAX 23-XX

3/16

42 1/4

7 1/4

10 1/2

COMBOMAX 34-XX

1/2

7 1/4

10 1/2

COMBOMAX 44-XX

3/4

49 1/2

9 1/2

3/4

12 1/2

COMBOMAX 64-XX

1/2

58 1/2

9 1/2

1/2

13 1/2

Page 3

!General Safety Precautions

Be sure to read and understand the entire Use & Care Manual before attempting to install or operate this water heater. Pay particular attention to the following General Safety Precautions. Failure to follow these warnings could cause property damage, bodily injury or death. Should you have any problems understanding the instructions in this manual, STOP, and get help from a qualified installer or technician.

Section 2 : Introduction

!WARNING

The important safeguards and instructions appearing in this manual are not meant to cover all possible conditions and situations that may occur. It should be understood that common sense, caution and care are factors which cannot be built into every product. These factors must be supplied by the person(s) caring for and operating the unit.

2.1LOCAL INSTALLATION REGULATIONS

This water heater must be installed in accordance with these instructions and must conform to local, or in the absence of local codes, with the current edition of the National Plumbing Code and the National Electric Code. In any case where instructions in this manual differ from local or national codes, the local or national codes take precedence.

2.2CORROSIVE ATMOSPHERE

The heater should not be located near an air supply containing halogenated hydrocarbons or high humidity. The limited warranty is voided when failure of the water heater is due to a corrosive atmosphere.

2.3 SHIPMENT INSPECTION

Inspect the water heater for possible shipping damage. The manufacturer’s responsibility ceases upon delivery of goods to the carrier in good condition. Consignee must file any claims for damage, shortage in shipments, or nondelivery immediately against carrier.

2.4 CHECKLIST

Please check the technical information plate to ensure you have the right model.

The following items are shipped with the unit :

•30 PSI pressure relief valve.

•Drain cock.

•Thermo manometer (heat and pressure indicator).

•Thermostatic mixing valve

! WARNING

The boiler should not be located in an area where leakage from the tank or water connections will result in damage to the adjacent area or to lower floors of the structure. When such areas cannot be avoided, a suitable drain pan or nonflammable catch pan, adequately drained, must be installed under the boiler. The pan must be connected to a drain.

NOTE: Auxiliary catch pan MUST conform to local codes.

COMBOMAXMC Electric boiler Set-up, use and care guide (revised January 2006), Page 4.

Section 3 : INSTALLATION

!WARNING

The manufacturer’s warranty does not cover any damage or defect caused by installation or attachment or use of any special attachment other than those authorized by the manufacturer into, onto, or in conjunction with the water heater. The use of such unauthorized devices may shorten the life of the water heater and may endanger life and property. The manufacturer disclaims any responsibility for such loss or injury resulting from the use of such unauthorized devices.

3.1 SAFETY MEASURES

All domestic and commercial installations will include a pressure relief valve limiting the operating pressure to 30 psi.

This COMBOMAXMC electric boiler is designed for a maximum operating temperature of 190°F. It is designed as a hot water heating system only. A 30 to 50% water and ethyleneor propylene-glycol blend is allowed.

3.2 LOCATION

The COMBOMAXMC water heater should be installed in a clean, dry location. Long hot water lines should be insulated to conserve water and energy. The water heater and water lines should be protected from exposure to freezing.

COMBOMAXMC water heaters must be installed vertically. Use the adjustable feet to level the unit.

The COMBOMAXMC water heater must be located or protected so as not to be subject to physical damage, for example, by moving vehicles, area flooding, etc..

All models can be installed on combustible floors and in alcoves. If the water heater is to be installed in a restaurant or other location where the floor is frequently cleaned, it must be elevated to provide at least 6 inches of clearance from the floor to comply with NSF International recommendations.

The room temperature must not exceed 80°F or 27°C.

3.3 CLEARANCE

The minimum clearances required for proper inspection and servicing are as follows:

Table 4: Clearances

Left side	3 inches
Right side	3 inches
Top	24 inches
Front	24 inches
Back	3 inches

3.4 SYSTEM SETUP

Figures 2, 3 and 4 are general connection diagrams including the circulator, the expansion tank, the drain cock, the safety valve, the air bleeder, the flow check valve and the thermo manometer. Set-up details follow.

3.5 HEATING WATER CIRCUIT

3.5.1 Connecting the heating water piping

The boiler may be set up alone or in parallel with others. Parallel connections should be made using the reverse-piping method to ensure equal flow through each boiler.

The boiler water supply connector is located on top of the boiler and the boiler water return connector is located to the left of the three-way valve. They are both threaded NPT female connectors.

Unions are recommended on the hot and cold water lines to disconnect the water heater easily for servicing if necessary.

Dielectric (insulating) unions are required for protection of the water heater if copper-steel connections are made.

Use only clean copper or approved plastic pipe for water connections. Local codes or regulations shall govern the exact type of material to be used.

Insulate all pipes containing hot water, especially in unheated areas.

COMBOMAXMC Electric boiler Set-up, use and care guide (revised January 2006), Page 5.

Install shutoff (ball) valves for servicing convenience. Install thermometers on the inlet and outlet lines.

Never plug the pressure relief valve to avoid creating a hazardous situation.

3.5.2 Flow-check valve

If the heating system uses a single circulator, a flow-check valve must be installed to minimize gravity flow and heat loss during nondraw periods.

3.5.3 Pressure relief valve

No boiler set-up is complete without a pressure relief valve. Its pressure rating must not exceed 30 psi (207 kPa). It must conform to the « ASME Boiler and Pressure Vessel Code» and limit the boiler operating pressure. It is a safety device, not a control device.

The BTU per hour rating of the relief valve must equal or exceed the BTU per hour input of the boiler(s) or heat source(s) as marked on the boiler(s) rating plate.

Connect the outlet of the relief valve to a suitable open drain, with the discharge at most 6” above the floor, far from any live electrical parts. The discharge line must pitch downward from the valve to allow complete draining and be no smaller than the outlet of the valve. The end of the discharge line should not be threaded or concealed and should be protected from freezing. No valve of any type, restriction or reducer coupling should be installed in the discharge line. Local codes shall govern the installation of relief valves.

3.5.4 Operating pressure control : expansion tank

Operating pressure control components ensure minimum and maximum operating limits are observed within the design operating temperature range. These components allow bleeding air from the piping, prevent boiling and cavitation at the circulator inlet, while minimizing the amount of fresh water input. Please contact a qualified plumber or contractor for more information on this subject.

The expansion tank connection point must be carefully chosen to prevent a situation where closing a valve would isolate the tank from the

boiler or any part of the circuit. It is preferable to use a calibrated diaphragm expansion tank.

3.5.5 Makeup valve

Connecting a makeup valve must be done according to code. This valve must include a flow-check valve to maintain the minimum operating pressure by admitting fresh water from the cold water supply line in case a leak occurs.

3.5.6 Air bleeder

There should be as little oxygen as possible in the heating circuit to prevent corrosion. As foreseen in section 3.5.4, this excludes the use of air as a pressure regulator within the circuit.

Installing manual or automatic air bleeders prevents air accumulation within the system. The bleeders must be set at the highest points of the system to purge any air accumulated during system set-up and to check its air tightness. Bleed the air regularly from the piping, making sure the heating water causes no bodily harm or material damage.

3.5.7 Circulator zoning

A flow-check valve must be installed in each zone, preferably at the outlet of each circulator, to prevent water flowing to zones where no heat is currently required. (see figure 4).

3.5.8 Zone valve zoning

Zone valves with low pressure drop are recommended. (see figure 3)

3.5.9 Circulator selection criteria

The COMBOMAXMC boiler includes a premounted circulator. The information below will help you select additional units for multiple circulator set-ups.

3.5.9.1 Pump flow rate calculation

The boiler output rating must correspond to the calculated heating load. Use the equation below to calculate the pump flow rate:

COMBOMAXMC Electric boiler Set-up, use and care guide (revised January 2006), Page 6.

Pump flow rate = Boiler output ÷ BWTD ÷ 500

•Pump flow rate is expressed in U.S. gallons per minute or GPM.

•The Boiler output ( in net BTU per hour) is the maximum amount of heat to be transferred through the heating circuit to meet the hot water demand.

•BWTD is the boiler water temperature drop through the heating circuit.

For example, a 24 Kw COMBOMAXMC boiler has a rated output of 81,964 BTU/hour. The system is designed for a boiler water temperature drop (BWTD) of 20°F.

Pump flow rate = 81,964 ÷ 20 ÷ 500 = 8,2 GPM.

The following table shows the required flow rate as a function of boiler water temperature drop (BWTD) and rated power output.

Table 5 : BWTD vs. flow (GPM)


Model	Kw		BWTD
Model	Kw	10o	20o	30o	40o
		F	F	F	F
COMBOMAX XX-8	8	5,5	2,7	1,8	1,4
COMBOMAX XX-10	10	6,8	3,4	2,3	1,7
COMBOMAX XX-15	15	10,2	5,1	3,4	2,6
COMBOMAX XX-18	18	12,3	6,1	4,1	3,1
COMBOMAX XX-20	20	13,7	6,8	4,6	3,4
COMBOMAX XX-24	24	16,4	8,2	5,5	4,1

3.5.9.2 Selecting a circulator

Consult the manufacturer’s operating characteristic curves to select the proper model. These curves plot flow versus pressure, together with other information such as efficiency and power. Ask your pump dealer or HVAC wholesaler to recommend the circulator which best fits your needs.

3.6 DOMESTIC HOT WATER CIRCUIT

3.6.1 Connecting the domestic hot water piping

The COMBOMAXMC domestic hot water coil may be set up alone or in parallel combination with other COMBOMAXMC units or storage tanks. Parallel connections should be made using the

reverse-piping method to ensure equal flow through each boiler.

The HOT WATER OUTLET and the COLD WATER INLET connections are clearly marked. Inlet water connections (COLD WATER INLET) are to be made to the copper pipe (sweat connection) at the bottom of the heater. Outlet water connections (HOT WATER OUTLET) are to be made to the three-way thermostatically controlled valve (sweat connection) at the top of the heater.

The installation of copper unions or copper alloy unions is recommended on the HOT and COLD water lines, so that the water heater may be easily disconnected for servicing if necessary. These unions must be dielectric (insulating) if you are making steel-copper connections.

A shutoff (ball) valve is present on the COMBOMAXMC domestic hot water outlet for servicing convenience.

Use only clean copper or approved plastic pipe for water connections. Local codes or regulations shall govern the exact type of material to be used.

Insulate all pipes containing hot water, especially in unheated areas.

Thermometer(s) should be installed to indicate the temperature of the water at or near the outlet of the water heater and storage tank(s), if provided.

3.6.2 Expansion tank on the cold water supply line

Determine if a flow check valve, a back flow preventer, a pressure-reducing valve, a water meter or a water softener is present on the cold water supply line.

A flow check valve creates a closed system and prevents the water, as it is being heated, from expanding back into the cold water supply line. Pressure can build up within the water heater, causing the pressure relief valve to operate during a heating cycle. This excessive operation can cause premature failure of the relief valve and possibly of the water heater itself.

Replacing the relief valve will not correct the problem. One method of preventing pressure build-up is to install an expansion tank on the

COMBOMAXMC Electric boiler Set-up, use and care guide (revised January 2006), Page 7.

cold water supply line between the COMBOMAXMC unit and flow check valve. Contact your installing contractor, water supplier, local plumbing inspector or plumbing supply house for assistance.

3.6.3Recirculation line (if applicable)

If a recirculation line is installed, the return connection should be made to a tee close to the inlet connection on the water heater. A check valve should always be installed in the recirculation line to prevent cold water from entering.

3.6.4Domestic hot water temperature and pressure relief valve

An automatic temperature and pressure relief valve must be installed at set-up time. No valve of any type should be placed between the safety relief valve and the water heater. Use a tee to set the relief valve onto the hot water outlet. The pressure rating of the relief valve must not exceed 150 psi.

The BTU per hour rating of the relief valve must equal or exceed the BTU per hour input of the boiler(s) or heat source(s) as recorded on the boiler(s) rating plate. For a circulating tank installation, the separate storage tank(s) must have similar protection.

3.6.5 Thermostatically controlled mixing valve (included)

For general-purpose hot water requirements in a domestic environment, a thermostatically controlled mixing valve is recommended to reduce the risk of scald injury. Contact a licensed plumber or the local plumbing authority for further information. Adjust the mixing valve to the lowest required temperature setting.

3.7 BOILER WIRING

The boiler cabling and grounding must conform to local codes or, in their absence, to the National Electrical Code.

Power must be provided by a 120/240 volt (single phase, 60 Hz) circuit, appropriately fused and with 3-wire plus ground cabling of sufficient gage. The fuse and cabling gauge may be determined from the boiler rating plate.

3.8 CIRCULATOR WIRING

The COMBOMAXMC heating pump (120 Vac, 1/25 Hp) is connected to the C&C terminals on the boiler electrical panel. The control circuit is designed to start the pump upon receiving a heating signal from the thermostat or priority aquastat.

3.9 CONNECTING THE THERMOSTAT

3.9.1 240V models

3.9.1.1 Single heating zone

Connect the low-voltage thermostat to the T&T terminals on the COMBOMAXMC electrical panel (DO NOT apply current to these terminals).

(see figure 10).

3.9.1.2 Zone valve zoning

Connect the low-voltage thermostat to the zone valve. The components must wired such that, upon a heating signal from a thermostat, only the corresponding zone valve will be actuated and will in turn activate the COMBOMAXMC circulator relay. Connect the zone valve switch to the T&T terminals on the COMBOMAXMC electrical panel (DO NOT apply current to these terminals). See figures 9 and 10.

The transformer used to power the zone valves must be of sufficient capacity to handle the load represented by all zone valves.

3.9.1.3 Multiple circulator zoning

Connect the low-voltage thermostat to the relay (Honeywell #RA-889, RA-89A). The components must wired such that, upon a heating signal from a thermostat, only the corresponding circulator will be activated. See figure 9.

3.10 PRIORITIZING TERMINAL POST

The K&K terminals on the electrical panel create a dry contact when the domestic hot water priority aquastat contact closes.

COMBOMAXMC Electric boiler Set-up, use and care guide (revised January 2006), Page 8.

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