Heater Craft 900H User Manual

ACU-HEAT

Installation and

Owners manual

For the following HEATER model numbers:

100H, 200H, 300H, 400H, 500H, 700H and 900H

INSTALLATION AND OWNERS MANUAL

Series Hydronic Heaters

Approximate Installation Time: 3-5 Hours

Tools Required:

#2 Phillips Screw Driver; Power Drill; 7/64" Drill Bit; 1"-4" Hole Saw; Jig Saw;

Hose Cutter; Wire Crimper; Teflon Plumbers Tape; Marine Sealant; Pencil.

cover

Guidelines And Definitions

These instructions contain information that is important for you to know and understand. The information
provided relates to safety issues for the installation and use of our products. To help you identify important
information, we use the following system.

Warning –

Important Safety information – A hazard that may cause an injur y, serious injury, or loss of life.

Caution –

Information for preventing improper operation of, or damage to equipment.

Note –

Information per taining to the installation, operation, and/or maintenance of this product that you should pay
special attention to.

Heater Craft will not be held liable for any accidental damage to persons and/or property resulting from any
installation not completed within the specified guidelines started herein.

Operation Warning

Carbon Monoxide (CO) is emitted from the engines' exhaust. Do not run the engine without proper
ventilation. Don not run the engine in a confined space or where back drafting may occur. For more
information about carbon monoxide refer to ABYC standards: A-7, T-22(1), and TH-23; or contact one of
the following agencies.

American Boat and Yacht Council, Inc   410-956-1050

United States Coast Guard    754-441-3287
 www.uscgboating.org

National Marine Manufacturers Association  313-946-6200
 www.nmma-medialink.com

Boat U.S.      703-823-9550
 www.boatus.com.

Heater Craft
6672 Boekel Road
Rathdrum, ID 83858
Attn: Technical Support
[phone]
Fax [phone]
www.heatercraft.com

Page 1

Heater System

1. Layout the heater system in the boat before installation and make sure the mounting location of the
heater unit and routing of all the hoses will work.

Warning – Do not mount the heater unit into the bilge area or any compartment that may draw air form
the bilge.

Types of Heater Installation:

 Ducted units typically mount under the helm or in a storage area that will allow routing of the vent 
 hoses to desired vent locations.

 Grill Mounted units typically mount into a stairwell of into a storage area.

Note – Our heater units are equipped with with 5/8" or 3/4" heater core outlets. Please make sure that you
have the proper size of heater hose and fittings for your installation. if the hoses and heater core outlets are
not the same size, it is necessary to install a hose coupling with the proper hose sizes to prevent coolant
leakage.

2. Determine your source for the hot water supply.

 Main engine – This installation is like your automobile, engine coolant will circulate from the engine
 to the heater unit and return to the engine.

Caution – If your engine application has a freshwater closed cooling system the heater unit should be
mounted below the level of the radiator cap. If heater is mounted above this level is is possible for air to be
come trapped in-line. IF there is air trapped in-line it will not allow the water to circulate efficiently and may
cause the engine to overheat. If the heater unit is mounted above the radiator cap it may be necessar y to
install an in-line air bleed valve at the highest point or an in-line circulation pump.

 Main engine with separate coolant loop for the heater – This installation will require additional  
 components. You will utilize a water exchanger to transfer heat from the engines' cooling system to 
 the heater loop. A pump is needed to circulate the water in the heater loop. Basic instructions are 
 outlined on page 8.

 Boiler-type system – Refer to the manufacture's instructions for hook-up information.

Note – Be sure the hoses are not kinked or pinched an any way, and do not contact any moving parts, sharp
objects or edges. They can be secured with a plastic tie.

3. Route and secure the heater water/coolant hoses between the heater unit location and the hot water
source.

Heater Craft
6672 Boekel Road
Rathdrum, ID 83858
Phone: [phone]
Fax: [phone]
www.heatercraft.com

Page 2

Engine

Warning – Hot engine coolant can cause severe burns! Never open the cap on a hot radiator. Some
vehicles are equipped with electric fans that may start without warning even with he engine shut off. Wait
until the engine has cooled completely before installation.

Note – Due to the wide variety of engine applications, the following are general instructions for a gasoline-

powered engine hook-up. please call Technical Support [phone] with your questions regarding your
specific engine application.

Always use silicone sealant or teflon tape on the threads of all fittings before installing to prevent
water/coolant leakage.

1. Refer to the engines manufacturers recomendations regarding the thermostat. The standard thermostat in
most factory applications is 142 degrees. The heater system will operate more effectively with a 160 degree
thermostat. If you are changing the thermostat, locate the thermostat housing on the engine. Remove the
existing thermostat and install a 160 degree thermostat. When installing a new thermostat, you may have to
replace the thermostat gasket or use RTV sealant.

2. Locate and remove the cooling system plug on the intake manifold. This would be located at the front of
the engine near the thermostat housing or on the thermostat housing itself. (On some applications it may be
necessary to rmove the temperature sending unit and install a brass tee.) Install the proper size hose barb.

Caution – The intake manifold also has vacuum ports. If you connect to a vacuum port, water/coolant will be
drawn into your engine and may cause internal damage.

Note – If you remove a sending unit, it is necessary to test the gauge operation after reinstalling to be sure it
is properly grounded.

The Hot water pressure will increase with engine RPM. This means on some applications the heater will cool
down during periods of extended idling. If your engine is normally operated at low engine RPM's it may be
necessary to install an in-line curculation pump. Please contact Technical Support [phone] for
options.

3. Locate and remove the plug on the water pump hosuing and install the proper size hose barb.

Note – If your particular engine does not have a plug to remove, it is necessary to install a hose tee into the
large hose connecting the thermostat housing to the water pump. Please contact Technical Suppor t (208)
687-4400 for options.

4. Cut the water/coolant hoses to length, attach with hose clamps, and secure in place.

Note – Fasten the hose clamps near the end of the hose to prevent the hose end from "mushrooming" and
to prevent coolant leakage.

Heater Craft
6672 Boekel Road
Rathdrum, ID 83858
Phone: [phone]
Fax: [phone]
www.heatercraft.com

Page 3