Amtrol HYDROMAX HM-41 Installation instructions

HYDROMAX®
INDIRECT-FIRED WATER HEATERS
INSTALLATION & OPERATION INSTRUCTIONS
Models HM-41 & HM-80
READ CAREFULLY THE PRODUCT
INSTALLATION & OPERATION INSTRUCTIONS.
FAILURE TO FOLLOW THE INSTRUCTIONS AND WARNINGS IN THE
MANUAL MAY RESULT IN SERIOUS OR FATAL INJURY AND/OR
PROPERTY DAMAGE, AND WILL VOID THE PRODUCT WARRANTY.
THIS PRODUCT MUST BE INSTALLED BY A LICENSED
PROFESSIONAL. FOLLOW ALL APPLICABLE LOCAL AND STATE
CODES AND REGULATIONS, IN THE ABSENCE OF SUCH CODES,
FOLLOW THE CURRENT EDITIONS OF THE NATIONAL PLUMBING
CODE AND NATIONAL ELECTRIC CODE, AS APPLICABLE.
DO NOT LIFT OR CARRY WATER HEATER BY THE
TOP COVER. WATER HEATER DAMAGE OR
PERSONAL INJURY MAY OCCUR IF THE COVER BECOMES DETACHED.
The heat transfer medium must be water or
other nontoxic fluid having a toxicity rating or
class of 1, as listed in Clinical Toxicology of Commercial Products,
5th edition. The pressure of the heat transfer medium must be limited
to 30 PSIG by an approved safety or relief valve.
This product can expose you to chemicals including
lead, which is known to the State of California to
cause cancer and birth defects or other reproductive harm. For more
information go to www.P65Warnings.ca.gov.
NOTE: Inspect for shipping damage and notify freight carrier or store where purchased immediately if damage is present. To avoid risk of personal
injury and property damage, if the product appears to be malfunctioning or shows signs of corrosion, call a licensed professional immediately. Current
copies of the Product manual can be viewed at www.amtrol.com. Use proper safety equipment when installing.
THIS IS THE SAFETY ALERT SYMBOL. IT IS USED TO ALERT YOU TO POTENTIAL PERSONAL INJURY AND OTHER
HAZARDS. OBEY ALL SAFETY MESSAGES THAT FOLLOW THIS SYMBOL TO REDUCE THE RISK OF PERSONAL
INJURY AS WELL AS PROPERTY DAMAGE.

• THIS PRODUCT MUST BE INSTALLED AND MAINTAINED BY
A LICENSED PROFESSIONAL PLUMBER, ELECTRICIAN, AS
APPLICABLE. IN ADDITION TO THE INSTRUCTIONS IN THIS
MANUAL, FOLLOW ALL APPLICABLE LOCAL AND STATE CODES
INCLUDING MA CMR 248 OR IN THE ABSENCE OF SUCH CODES,
THE CURRENT EDITIONS OF THE NATIONAL PLUMBING CODE
AND THE NATIONAL ELECTRIC CODE.
• DRIP PAN AND DRAIN: This appliance should not be installed in
an area where leakage of the tank or connections can result in
damage to the area adjacent to the appliance or to lower floors of
the structure. When such locations cannot be avoided, a suitable
drain pan, adequately drained and kept clear, must be installed
under the appliance.
• CAUTION: Determine whether your water is corrosive or acidic,
and that there are no suspended solids, toxic or other substances
or abnormally high chlorine levels in the water that could damage
or affect the water heater or the rest of your plumbing system.
USEGLYCOLONLYWITHDOUBLE-WALLED
HEAT EXCHANGER MODELS. Glycol is a
poisonous substance. To avoid seepage or leakage of glycol to
surfaces where humans or animals can ingest it, use glycol only
in double-walled units, so that any leaks will most likely be
released to the atmosphere. However, a leak to a surface area
may still occur, so any use of glycol must be monitored closely
and humans and animals should be protected from contact with
the unit.
Do not connect the water heater domestic
supply with baseboard or other space
heating units or elements. Any contaminants in the baseboard
units will contaminate the potable water in the water heater and
also adversely affect its performance.
• Wiring Options. Select either a Non-Priority or Priority System:
Two options are available when wiring the controls of the water heater
in the space heating system (boiler and distribution elements).
1. Non-Priority System - The controls of the water heater must be
wired as a separate heating zone with a standard zone valve or a
separate circulator dedicated to the water heater “zone”.NOTICE: In
this non-priority option, the water heater will be supplied just as another
zone. This means that if all space heating zones call for hot boiler water
at the same time, the water heater may not be supplied with enough
hot boiler water to “recover” adequately. The delivery of domestic
hot water will be diminished. In many, but not all cases, this is not a
problem because the routine oversizing of boiler output is adequate for
both loads.
2. Priority System - Under this wiring option the water heater will be
supplied before space heating.
In limited circumstances, space heating can
be lost in the home in this priority mode. Any
demand for space heating is postponed until the water heater has
reached its 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 malfunctions such as circulator or
thermostat failure, space heating could be delayed indefinitely. If
undetected and uncorrected, freezing damage to piping could result.
• Select Circulator versus Zone Valve
The flow of hot boiler water to the water heater can be controlled with
either a motorized zone valve or a circulator.
1. Separate circulator. The recommended way to provide adequate flow
through the water heater heat exchanger is to use a separate dedicated
circulator. This option may be used even though the heating system
utilizes zone valves.
2. Zone valve If a zone valve is to be used, a flow rate of 3 to 5
gpm with all zones in use is required. A full-port zone valve should
be used.
• All installations require a low-water cut-off or automatic fill valve on your
boiler system to reduce the risk of boiler water loss.
• Steam boiler installations require a low-water cut-off which is also
required by most codes.
• Installation of a vacuum breaker is required to prevent damage to the
water heater when drained. There must be no valves installed between
the vacuum breaker and water heater.
2. Pre-Installation Checklist
IMPORTANT STEPS AND DECISIONS REQUIRED BEFORE INSTALLATION
-2-
1. Table Of Contents
Pre-Installation Checklist................................................................. 2
Required Components and Accessories Checklist ......................... 3
HYDROMAX®Plumbing .................................................................. 4
Ener-G-NET™Wiring ....................................................................5-6
Ener-G-NET Setup & Adjustment ................................................... 7
Mechanical Aquastat Wiring............................................................ 8
Startup Procedure ........................................................................... 9
Troubleshooting............................................................................... 9
General Safety Information ........................................................... 10
Replacement Parts........................................................................ 11
PLEASE READ THE FOLLOWING INSTRUCTIONS CAREFULLY
IMPORTANT GENERAL SAFETY INFORMATION -
ADDITIONAL SPECIFIC SAFETY ALERTS APPEAR IN THE FOLLOWING INSTRUCTIONS.

3. Required Components And Acessories Checklist
-3-
If a steel hydropneumatic tank is
in place, replace it with a properly
sized diaphragm expansion tank. Otherwise, significant
heat transfer problems can occur by causing air to be
trapped in the heat exchanger. If the boiler system has
an existing expansion tank and the boiler temperatures
are being changed, resize the existing diaphragm
expansion tank.
Use care when using a torch
near the top cover and heat
exchanger plate. It is recommended that the front half
be removed prior to soldering to avoid potential damage.
Boiler Return
Cold Water
Inlet
Retaining Screws (2) Heat Trap
Boiler Supply
Hot Water
Outlet
15
10
5
0
0 2 4 6 8
Head Loss (Feet)
Flow (Gallons Per Minute)
HYDROMAX®Components (Single Wall Shown) Two-Piece Cover Removal and Installation
Heat Exchanger Pressure Loss
MODEL CIRCULATOR
PERFORMANCE ZONE VALVE SHUTOFF VALVES RELIEF VALVE
THERMAL
EXPANSION
TANK
HM-41 4 GPM @ 6 FT 3/4" Full Port 4 Included 2.0 Gallon
HM-80 4 GPM @ 6 FT 3/4" Full Port 4 Included 4.4 Gallon
Removing Front Half:
Depress both tab buttons to
detach one side at a time.
Installing Front Half:
Align bottom groove of cover
onto metal retaining ring.
Beginning with one side,
align pin and push until both
tabs lock. Repeat for other
side, ensuring all tabs are
fully engaged.
Removing Entire Cover:
Remove front half, loosen
both retaining screws and
remove rear half.
Tab Buttons (4)

-4-
4. HYDROMAX®Plumbing
DOMESTIC WATER PIPING
1. Connect the cold water supply to the pipe labeled COLD WATER.
2. Connect the HOT WATER piping to the domestic hot water system.
3. When all domestic water piping is complete, open the cold water supply
and allow some water to enter the tank. Look and listen for signs of
leaks and repair as necessary before continuing.
NOTE: If installing on a city supply, a properly sized thermal expansion
tank is required and should be installed in accordance with the product
installation manual.
NOTE: If a water heater is installed in a closed water supply system,
such as one having a back-flow preventer in the cold water supply,
means shall be provided to control thermal expansion. Contact
the water supplier or local plumbing inspector on how to control
this situation.
NOTE: If an external electrical source is utilized, the appliance, when
installed,must be electrically grounded in accordance with local codes
or, in the absence of local codes, with the National Electrical Code,
ANSI/NFPA 70.
NOTE:The thermostat is adjusted to 120°F when shipped from
the factory.
4. Install a blowdown tube on the T&P relief valve outlet. Plumb to within
6 inches above a floor drain or as directed by plumbing code.
Do not drill, puncture or otherwise penetrate
the steel outer tank shell. Do not screw pipe
hangers or other hardware into the exterior of the tank.
BOILER PIPING
1. Plumb the circulator or zone valve on the BOILER SUPPLY line.
2. Pipe the BOILER RETURN connection to the boiler return line.
Be sure the return line is NOT plumbed to the
suction side of any heating circulators. This
may require moving the heating circulator off the boiler tapping on
packaged boilers. Failure to do so will result in overheating and tank
damage when the heating system is in operation.
3. Install a weighted flow check on the boiler return line. This is not
necessary on systems utilizing a zone valve to control the water
heater temperature.
4. After completing the boiler piping, slowly open the boiler fill valve
and pressurize the water heater loop. Check for leaks and repair as
necessary. Proceed to the appropriate wiring section in this manual.
EXPLOSION HAZARD. Do not install to a high
pressure steam boiler (greater than 15 psig).
An explosion could occur.
LEFT SIDE ..............1"
RIGHT SIDE.............1"
TOP ...................9"
REAR ..................1"
FLOOR .................0"
FRONT .................1"
Clearance From Combustible Surfaces
LEFT..................12"
RIGHT ................12"
FRONT ................30"
HEAD ROOM ......... 36"
REAR ................ 1"
Recommended Clearance for Servicing
PIPING USING ZONE VALVE
REAR VIEW (FOR CLARITY)
DRAIN
CONTROL
PANEL
TOP
COVER (2)
PIPING
CONNECTIONS
COMPONENT
LOCATIONS
T&P VALVE
COLD
SUPPLY
HOT
OUTLET
BOILER
RETURN
BOILER
SUPPLY
Double Wall Models
BOILER RETURN
Single Wall Models
BOILER SUPPLY
HOT
OUTLET
COLD
SUPPLY

5. Ener-G-NET™Wiring
-5-
Ener-G-NET incorporates all of the temperature sensing and control
necessary for HYDROMAX®operation. Built-in switching relays may be
wired to operate the boiler control and circulator pump or zone valve. The
diagram below illustrates these internal switching functions.
Examples of common wiring scenarios are provided on the following page.
After wiring is complete, insert the temperature sensor (thermistor) plug into the receptacle at the base of the digital control.
NOTE: Line-voltage and safety-circuit wiring which is external to the
water heater jacket when all panels are in place, and which is part of
the appliance, shall be protected by metal conduit, metal-clad cable or
raceways. Thermoelectric wiring shall be exempt from this provision.
NOTE: Strain relief shall be provided for all conductors leaving an
enclosure. For low-voltage wiring, strain relief at the point of exit from an
enclosure is not necessary if, by wire location or support, protection is
provided against accidental strain.
Normally Open
Close on call for hot water
Post-Purge function
Front Panel
Control
Screws (4)
Wiring Cover
Ground Screw
Conduit Holes (3)
Normally Open
Close on call for hot water
Normally Closed
Open on call for hot water
Priority function
Constant 24VAC or 120VAC Power In
{
{
{
{
ORANGE
ORANGE
BLUE
BLUE
VIOLET
VIOLET
WHITE
BLACK
Temperature
Sensor Plug

-6-
Ener-G-NET™Wiring
Common wiring diagrams are shown below. Select the appropriate
diagram for the application. Diagrams are popular examples only. If
your application is not shown, contact Amtrol Technical Support at
401.535.1216. NOTE: Ensure the Ener-G-NET installation is within the
following application and operating parameters:
• Ambient temperature from 38° to 125°F.
• Relative humidity ranging from 20% to 90% (non-condensing).
• Boiler load rating up to 15A resistive, 1/4hp inductive @ 120VAC.
• Circulator load rating up to 15A, 1/4hp inductive @ 120VAC.
• Space heating load rating up to 8A @ 120VAC.
HYDROMAX®
CIRCULATOR
HEATING
CIRCULATOR
ORANGE
ORANGE
WHITE
BLACK
BLUE
BLUE
VIOLET
VIOLET
POWER BURNER PUMP PRIORITY
ZR Input Terminal
L1 ZR C1
C2
L2
HYDROMAX™
CIRCULATOR
HEATING
CIRCULATOR
ORANGE
ORANGE
WHITE
BLACK
BLUE
BLUE
VIOLET
VIOLET
POWER BURNER PUMP PRIORITY
24 Volt
L1 B
Z
W
C1
C2
L2
HYDROMAX®
CIRCULATOR
HEATING
CIRCULATOR
ORANGE
ORANGE
WHITE
BLACK
BLUE
BLUE
VIOLET
VIOLET
POWER BURNER PUMP PRIORITY
High Limit (B Terminal)
L1 B C1
C2
L2
ORANGE
ORANGE
WHITE
BLACK
BLUE
BLUE
VIOLET
VIOLET
POWER BURNER PUMP PRIORITY
HYDROMAX®
CIRCULATOR
HEATING
CIRCULATOR
L1 BB2
Z W
C1
C2
L2
Millivolt
HYDROMAX®
CIRCULATOR
HEATING
CIRCULATOR
ORANGE
ORANGE
WHITE
BLACK
BLUE
BLUE
VIOLET
VIOLET
POWER BURNER PUMP PRIORITY
Triple-Aquastat
L1 BR C1
C2
L2
HYDROMAX®
CIRCULATOR
HEATING
CIRCULATOR
ORANGE
ORANGE
WHITE
BLACK
BLUE
BLUE
VIOLET
VIOLET
POWER BURNER PUMP PRIORITY
L1 BB2 C1
C2
L2
Self-Generating
Oil Burner Controls
Gas Valve Controls
Other Applications
HYDROMAX®
CIRCULATOR
DHW ZONE
ORANGE
ORANGE
WHITE
BLACK
BLUE
BLUE
VIOLET
VIOLET
POWER BURNER PUMP PRIORITY
Multi-Zone Control: Using Post Purge
L1L2
TO BOILER
XX
HYDROMAX®
CIRCULATOR
OR ZONE VALVE
DHW ZONE
24 OR 120VAC
ORANGE
ORANGE
WHITE
BLACK
BLUE
BLUE
VIOLET
VIOLET
POWER BURNER PUMP PRIORITY
Multi-Zone Control: No Post Purge
L1L2
TO BOILER
XX
HYDROMAX®
CIRCULATOR
Z
I
ORANGE
ORANGE
WHITE
BLACK
BLUE
BLUE
VIOLET
VIOLET
POWER BURNER PUMP PRIORITY
Outdoor Reset/Automatic Temperature Control
L1 ZC ZRL2
ZONE/INDRIECT SWITCH
(IF EQUIPPED)
SELECT “INDIRECT”
ZONE VALVE
END
SWITCH
MOTOR
24VAC
ORANGE
ORANGE
WHITE
BLACK
BLUE
BLUE
VIOLET
VIOLET
POWER BURNER PUMP PRIORITY
4-Wire Zone Valve
TRANSFORMER
L1L2

6. Ener-G-NET™Control Setup & Adjustment
-7-
Ener-G-NET features two distinct programming areas: User Modes and
Installer Settings. User Modes consist of three end-user functional
modes, while Installer Settings are primarily accessed upon initial setup
to specify critical operating parameters. Ener-G-NET factory defaults allow
traditional operation suitable for most homes. To optimize the control setup,
reference the tables below.
Temperature settings above 120° F can create a
scald hazard.
Mode
Indicators
User
Modes
Installer
Settings
LED
Display
User Mode Code Description
Standard
Efficiency
Vacation
On-Demand sensing reduces fuel consumption by limiting boiler operation during idle periods.
Traditional operation within preset temperature differential using a low and high limit.
Reduced temperature setting minimizes boiler operation during anticipaated periods of non-use.
User Modes are used to select from three distinct operational modes. To select, press the green MODE button and press again to cycle through the three
available modes. A green dot illuminates to display the current mode.
Indicator Code Description
Startup Test
Idle
Heating
Displayed briefly during intial powerup to test LED display segments.
Operating Indicators are used to display operational and functional status. Water sensor temperature may be shown for 30 seconds by pressing
the ▲ button.
Static numeric [setpoint] readout (factory default shown) indicates domestic hot water setpoint.
Alternating On and [Setpoint] is displayed during a heating cycle while the circulator pump contacts are closed.
Setting Code Description Range
Temperature Domestic hot water setpoint. Default is 120°F 90-150
Differential Domestic hot water temperature drop before call for heat. Default is 10°F. 5,10*
Post-Purge Early boiler shutoff prior to hot water setpoint. Circulator runs until setpoint. Default is 0°F. 0,4,8**
Priority Temporarily cancels space heat to maxmize available energy for hot water. Default is 'n'. y/n
Capacity Water heater capacity; select appropriate size for proper operation. Default is 41 Gallons. 26,41,60,80,120
BTU Transfer Real-time BTU transfer estimate in 1000 BTU/Hr increments. Diagnostic readout only. 0-199MBH/Hr
*Available in Standard Mode only.
**Available only when Differential setting is 10.
Installer Settings are used to adjust functional operating parameters. To adjust, press and hold the SET button until the Temperature setting appears.
Cycle through settings by depressing the SET button and using the ▼and ▲buttons to change the settings.
Error Code Description Potential Causes***
Temp Sensor Temperature sensor (thermistor) fault. Sensor unplugged
Sensor damaged
Overheating Domestic hot water temperature has exceeded maximum setpoint.
Error in boiler plumbing
Zone valve stuck open
Leak in sensor well
Slow Heating Unit has taken over 60 minutes to reach hot water setpoint or cannot reach setpoint.
Faulty equipment
Fouled heat exchanger
No fuel
***See Troubleshooting section for additional information
Diagnostic Error Codes display a visual indicator and sound an alarm if a fault is detected. Codes clear automatically when corrected or can be reset by
interrupting power to the control for 5 seconds. To silence an alarm, depress the ▼on the keypad.

-8-
7. Mechanical Aquastat Wiring Diagrams
Common wiring diagrams are shown below. Select the appropriate diagram for the application. Diagrams are popular examples only. If your application
is not shown, contact Amtrol Technical Support at 401.535.1216.
AQUASTAT
HYDROMAX®
CIRCULATOR
COIL
2
31
4 6
5
HONEYWELL
R4222D 1013
OR EQUIVALENT
DPDT RELAY
WHEN NO “ZR” TERMINAL IS AVAILABLE
GO TO THE SUPPLY SIDE OF THE HI LIMIT
L1
L2
ZR
Typical Oil Burner (Non-Priority)
AQUASTAT
3-Wire
ZONE VALVE
24VAC
END
SWITCH
TRANSFORMER
L1L2
AQUASTAT
Multi-Zone Control
HYDROMAX®
CIRCULATOR
OR ZONE VALVE
DHW ZONE
L1L2
TO BOILER
XX
AQUASTAT
HYDROMAX®
CIRCULATOR
COIL
2
31
4 6
5
HONEYWELL
R4222D 1013
OR EQUIVALENT
DPDT RELAY
Z
W
L1
L2
B
Typical Gas Valves (Non-Priority)
AQUASTAT
ZONE VALVE
MOTOR
24VAC
END
SWITCH
TRANSFORMER
L1L2
4-Wire
AQUASTAT
Boiler Control Input
HYDROMAX®
CIRCULATOR
OR ZONE VALVE
DHW ZONE
Boiler Controls
Zone Valves Universal Sensor Kit
Other Applications
AQUASTAT
SENSOR BULB
(REMOVE)
BOILER CONTROL
EXTENSION
CABLE PLUG
UNIVERSAL SENSOR
IN SENSOR WELL
HYDROMAX®
BOILER
DHW
Installing Universal 10K Ohm Sensor Kit
HYDROMAX models with a mechanical aquastat
include a universal temperature sensor kit allowing
HYDROMAX to be used with any boiler control featuring
a standard “10K” DHW thermisor input (10,000 Ohms at
77°F). When installed, domestic water temperature is
regulated by the boiler and the HYDROMAX aquastat
is not used.
1. Unscrew and remove copper sensor bulb from
sensor well.
2. Insert Universal Sensor to bottom of sensor well.
3. Cut male plug from end of sensor cable, strip
sheathing and wire insulation from end.
4. Connect wire leads to DHW input terminals on
boiler control.

-9-
PROBLEM POSSIBLE CAUSES SOLUTION
No hot water
1. No power to unit
2. Circulator air-bound
3. Faulty circulator or zone valve
4. Faulty control
5. Boiler inoperable
1. Check circuit breaker, boiler emergency switch and boiler reset switch.
2. Purge air. Ensure circulator is on Boiler Supply. Check air vents.
3. Check circulator and zone valve. Repair or replace if necessary.
4. Check continuity. Switching circuits should close. If not, replace control.
5. Check boiler system. Boiler must operate to generate hot water.
Insufficient hot water
1. Demand exceeds capacity
2. Temperature too low
3. Boiler lacks output for simultaneous heat & hot water
4. Fouled heat exchanger
5. Insufficient heat exchanger flow
1. Check sizing based on household size and boiler output.
2. Increase temperature setpoint.
3. Set up for priority. If problem persists add storage or increase tank size.
4. Check Boiler Supply/Boiler Return during cold startup. If difference is
less than 20°F, clean heat exchanger as outlined below. Install water
treatment equipment to prevent recurrence.
5. Check for undersized or faulty circulator, stuck or undersized zone valve.
Ensure all shutoff valves are open. Check for stuck flow check valve.
Purge boiler loop to remove air.
Water too hot
1. Improper plumbing
2. Temperature set too high
3. Temperature sensor not fully inserted
4. Stuck zone valve
5. Flow check valve stuck open
1. If Boiler Return is plumbed to the suction-side of a heating circulator,
overheating will occur when the home’s heat is on. Fix plumbing.
2. Reduce temperature setting.
3. Re-insert temperature sensor.
4. Repair or replace.
5. Clean, repair or replace.
Relief valve dripping or
opening
1. Thermal expansion tank undersized or missing
2. Thermal expansion tank set improperly
3. City pressure too high
4. System over temperature
5. Faulty relief valve
1. Install the properly sized thermal expansion tank.
2. Ensure precharge air pressure matches static water pressure.
3. Install a Pressure Reducing Valve (PRV) if city pressure is over 80 psi.
4. Determine cause of over temperature condition and correct problem.
5. Replace relief valve.
Discolored water
at faucet
1. Poor water quality
2. Sediment or suspended particles
1. Have water tested for contaminants.
2. Install sediment filter, purge unit more often to avoid future problems.
Boiler will not operate
when calling for
hot water
1. Improper or loose wiring
2. Boiler high limit has been reached
3. Post Purge (POS) set too high
4. Problem with boiler system
1. Check connections against wiring diagrams in this manual.
2. Boiler will periodically cycle on and off during operation.
3. Post Purge shuts the boiler off prior to reaching domestic setpoint. If
set too high, the boiler may not have enough energy to raise the water
temperature to setpoint. Reduce POS or set to 0 if the problem persists.
4. Have boiler diagnosed for proper operation.
8. Startup Procedure
9. Troubleshooting
1. Purge Heat Exchanger: The heat exchanger should be free of large air
pockets to allow the circulator to operate properly. Using the diagram
below as a guide, isolate the boiler return line and flush the loop until large
air pockets are purged. After this, the air elimination equipment will collect
smaller air bubbles.
2. Fill Tank: Open the hot water fixture furthest from the heater. Open the cold
water supply and allow the water to run until air stops emerging. Air pockets
may appear at any hot water fixture. This is considered normal and will clear
as hot water is used.
3. Start Heater: Turn power on to the unit. Digital Control models come pre-set
to 120°F for safety. Mechanical controls should have the knob rotated to
the 120°F mark. The circulator or zone valve should operate and the boiler
should start.
4. Check Operation: The water heater will begin to heat. Depending upon the
size of the water heater, output of the boiler and the space heating load, the
unit should typically reach set temperature within 15 to 60 minutes. If heating
does not occur, consult the troubleshooting section in this manual. Note:
Large heaters coupled with small boilers may exceed this time period upon
initial startup.
5. Set Temperature: The control should be set to the minimum temperature
consistent with the user’s needs. This maximizes efficiency and reduces
scald potential.
6. The water heater and system should be periodically checked by a licensed
professional at least annually and more often as system ages.
1. Close
Return 3.
Purge
Air
2. Fill
Boiler

SCALDING HAZARD.If the water temperature is
over 120°F., household members can suffer serious
or fatal scalding and painful and permanent injury.
• The Consumer Products Safety Commission recommends an initial
setting of 120°F., but advised that a slower response time of infants,
aged, disabled and other persons increases the scalding hazard and
may require lower settings.
• Always check the water temperature before use, including washing,
bathing or showering.
• Temperature limiting valves are available from your plumbing supplier. A
check valve must be installed in the boiler return line to prevent gravity
flow through the heat exchanger. This can cause overheating and result
in serious or fatal scalding.
SCALDING HAZARD. If the thermostat is not
working properly or if this product is not installed in
accordance with the manual, water temperature can reach excessive
levels that may cause serious or fatal scalding. After installation and any
servicing of the unit, verify that the thermostat is working and firmly
inserted in the thermostat well by following the thermostat testing
instructions in the manual.
Failure to use the correct replacement parts may
make your product unsafe.
In limited circumstances, space heating can be lost
in the home with unit utilizing priority mode. Any
demand for space heating is postponed until the water heater has
reached its 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 malfunctions such as circulator or
thermostat failure, space heating could be delayed indefinitely. If
undetected and uncorrected, freezing damage to piping could result.
If a steel hydropneumatic tank is in place, replace it
with a properly sized diaphragm expansion tank.
Otherwise, significant heat transfer problems can occur by causing air to
be trapped in the heat exchanger. If the boiler system has a diaphragm
expansion tank and the boiler temperatures are being changed, resize the
expansion tank.
If installing on city water supply, a properly sized
thermal expansion tank is required with the water
heater and should be installed as set forth in the product installation
manual. Contact your water supplier or local plumbing inspector for
additional information.
Prevent pressure build-up in any existing internal
tankless coil. Do not plug incoming or outgoing
tappings in the internal tankless coil plate. Leave the coil in the boiler and
leave system connections open to prevent pressure build-up.
Electrocution hazard. The water heater must be
electrically grounded. Electrical supply must come
from the boiler side of boiler’s emergency shut-off switch in order to
prevent unsafe boiler operation.
Chlorine Aggressive Water: The water quality can
significantly influence the life of this Product. You
should test for corrosive elements, acidity, total solids and other relevant
contaminants, including chlorine and treat your water appropriately to
insure satisfactory performance and prevent premature failure.
NOTE: Inspect for shipping damage and notify freight carrier or store
where purchased immediately if damage is present. To avoid risk
of personal injury and property damage, if the product appears to be
malfunctioning or shows signs of corrosion, call a licensed professional
immediately. Current copies of the Product Manual can be obtained at the
place of purchase. Use proper safety equipment when installing.
EXPLOSION HAZARD.The pressure of the heat
transfer medium must be limited to a maximum of
30 psig by an approved safety or relief valve on your boiler. The water
heater pressure must be limited to 150 psig maximum by the installation
of a temperature and pressure relief valve (included). The relief tube must
be plumbed to a suitable drain per code. No reducing coupling or other
restriction may be placed in this line.
This Product, like most Products under pressure,
may over time corrode, weaken and burst or
explode, causing serious or fatal injury, leaking or flooding and/or property
damage. To minimize risk, a licensed professional must install and
periodically inspect and service the Product. A drip pan connected to an
adequate drain must be installed if leaking or flooding could cause
property damage. Do not locate in an area where leaking could cause
property damage to the area adjacent to the appliance or to lower floors
of the structure.
EXPLOSION OR RUPTURE HAZARD. A relief
valve must be installed to prevent pressure in
excess of local code requirement or maximum working pressure
designated in the Product Manual, whichever is less. Do not expose
Product to freezing temperatures or temperatures in excess of the
maximum rated operating temperature.
If not installed by the boiler manufacturer, install a
low water cut-off or pressure reducing valve on your
boiler so that leaking will not result in a dry boiler which if the boiler
continues to fire, will cause an explosion hazard.
This unit must be installed as a separate heating
zone. Do not connect this unit to an existing heating
zone or feed boiler water directly through the coil as dangerous
over-heating will result.
Do not drain this appliance before shutting off the
supply valve and opening the relief valve or
another downstream fixture, as it will damage this unit. A vacuum breaker
should be installed to avoid damaging the liner. Damage to the unit and
leakage can occur if a vacuum breaker is not installed.
USE GLYCOL ONLY WITH DOUBLE-WALLED
HEAT EXCHANGER MODELS. Avoid risk of
ingesting a toxic glycol fluid. The heat transfer medium should be water.
If glycol must be used, it should only be used with double-walled heat
exchangers and closely monitored for leakage.
As in all plumbing products and water storage
vessels, bacteria can grow in this Product, especially
during times of non-use. Consult your local plumbing professional
regarding any steps you may wish to take to safely disinfect your home’s
plumbing system.
EXPLOSION OR RUPTURE HAZARD! A relief
valve must be installed to prevent pressure in
excess of local code requirement or maximum working pressure
designated in the Product Manual, whichever is less. At least once every
3 years or if discharge is present, a licensed contractor should inspect the
temperature and pressure relief valve and replace if corrosion is evident
or the valve does not function. FAILURE TO INSPECT THIS VALVE AS
DIRECTED COULD RESULT IN UNSAFE TEMPERATURE OR
PRESSURE BUILD-UP WHICH CAN RESULT IN PRODUCT FAILURE,
SERIOUS INJURY OR DEATH AND/OR SEVERE PROPERTY DAMAGE
AND VOID THE PRODUCT WARRANTY.
10. General Safety Information
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Description ID HM-41 Models HM-80 Models
Heat Exchanger Replacement Kit, Single Wall 1 393465 393448
Heat Exchanger Replacement Kit, Double Wall 1 2800R001 2801R001
Top Cover Half (2 Required) 2 393381 393381
Digital Control Upgrade Kit with Panel 3 396411 396411
Digital Temperature Control 4 396413 396413
Temperature Sensor for Digital Control - 393281 393281
Mechanical Temperature Control only 5 393232 393232
Cold Water Inlet Tube 6 393199 393168
T&P Safety Relief Valve 7 393107 393107
Bottom Drain Assembly 8 9340R160 9340R160
11. REPLACEMENT PARTS
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8
1
6
72
4
5
3

© 2021 Worthington Industries Inc. Part #: 9040-694 (06/21)
One or more features of this product are covered by U.S. patents, visit www.amtrol.com/patents for more information.
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