Hubbell Electric Heater Company SLN Operating instructions

OPERATING AND MAINTENANCE MANUAL FOR
COMMERCIAL SOLAR WATER HEATER
ELECTRIC HEATER COMPANY
BASE MODEL “SLN”

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HUBBELL
ELECTRIC HEATER COMPANY
P.O. BOX 288
STRATFORD, CT 06615
PHONE: [phone]
FAX: [phone]
INTERNET: http://www.hubbellheaters.com/
-- IMPORTANT --
Always reference the full model number and serial number when calling the factory.
WARNING / CAUTION
1. Tank is to be completely filled with water and all air is to be vented before energizing.
2. Due to the rigors of transportation, all connections should be checked for tightness before heater
is placed in operation.
3. Safety relief valve must be installed in tapping provided.
4. KEEP AWAY FROM LIVE ELECTRICAL CIRCUITS.
Do not perform any maintenance, make any adjustments, or replace any components inside the
control panel with the high voltage power supply turned on. Under certain circumstances,
dangerous potentials may exist even when the power supply is off. To avoid casualties, always
turn the power supply safety switch to off, turn the charge or ground the circuit before
performing any maintenance or adjustment procedure.
5. The unit is designed to operate at pressure not more than 150 psi.
6. Generalized instructions and procedures cannot anticipate all situations. For this reason, only
qualified installers should perform the installations. A qualified installer is a person who has
licensed training and a working knowledge of the applicable codes regulation, tools, equipment,
and methods necessary for safe installation of an electric resistance water heater. If questions
regarding installation arise, check your local plumbing and electrical inspectors for proper
procedures and codes. If you cannot obtain the required information, contact the company.

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TABLE OF CONTENTS
SECTION TITLE PAGE #
I GENERAL DESCRIPTION AND CONSTRUCTION 5
II INSTALLATION 8
III SCHEDULED MAINTENANCE AND OPERATION 11
IV TROUBLESHOOTING 13
V SERVICING AND REPLACEMENT OF PARTS 15

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5
SECTION I - GENERAL DESCRIPTION AND CONSTRUCTION
GENERAL DESCRIPTION
This book describes a packaged solar water heater that is a stationary, self-contained unit. The complete
assembly on a standard unit consists of the storage tank, immersion heating coil, and an ASME rated
combination temperature and pressure safety relief valve. The water heater heats domestic potable
water by transferring heat from the solar loop (typically ethylene glycol) to the domestic water via an
immersion heating coil inserted into the water heater tank. Optional equipment may be supplied with
your unit. Please consult the product drawing for details specific to your assembly. The unit is factory
assembled, insulated, jacketed, wired, and tested.
CONSTRUCTION
TANK
The standard storage tank is constructed of steel and internally lined with specially formulated
Hydrastone cement to a ½-inch minimum thickness. The tank is designed for a maximum allowable
working pressure of 150 psi (300 psi TP).
TANK CONNECTIONS
The heater is supplied with separate cold water and hot water connections. Water entering the cold
water inlet is deflected by means of a baffle within the tank. The hot water outlet includes a built in heat
trap to prevent hot water from radiating out from the heater. A ¾-inch FNPT connection is located on
the side of the heater for mounting a combination safety temperature and pressure relief valve. An
overflow line should be installed from the relief valve outlet to a floor drain. A ¾-inch GHT connection
is supplied for draining. See drawing for locations and sizes.
HEATING COIL
The water heater is supplied with a high quality, factory installed, high efficiency, single walled,
copper finned heating coil designed for a maximum working pressure of 150 psi. The tubing is
installed in a heavy-duty fabricated steel head with threaded NPT connections. Each assembly is
fastened to a corresponding tank flange using a gasket and hex head steel bolts and nuts. Double
walled tubing may be supplied as an option.

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OUTER SHELL AND INSULATION
The tank is encapsulated in 2-inch thick polyurethane foam insulation. The insulation is protected by a
high impact non-corroding colorized composite protective jacket.
THERMISTOR CLIP
The water heater is supplied with a thermistor clip located just above the heating coil tank flange for
attaching a sensing probe to the water heater tank. Temperature sensors and controls are not included
with the water heater.
OPTIONAL BACK-UP ELECTRIC HEATING SYSTEM
Back-up Electric Heating Element
The water heater may be supplied with an electric immersion heating element assembly(s), composed
of a copper sheathed element(s) that are brazed into a brass flange. Each assembly is fastened to a
corresponding tank flange using a gasket and four (4) 3/8-16 x 1-inch long hex head steel bolts and
nuts. See drawing for voltage and power ratings.
Control Thermostat
The water heater may be supplied with either a surface mounted or immersion thermostatic switch to
control the back-up electric heating system. See drawing for specific details. The surface mounted
thermostat can be adjusted through a range of 110° - 170° F. The immersion thermostat can be adjusted
through a range of 100° - 190° F. Both thermostats are adjustable with a flat tip screwdriver.
Surface Mounted Thermostat
ImmersionThermostat

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Temperature High Limit Switch
As a safety device, either a surface mounted high temperature cut-off switch with manual reset, factory
set at 190° F, or an immersion high temperature cut-off switch with manual reset, factory set at 180° F,
may be provided. In the event of an over-temperature condition, the thermostat will disengage the
power from the back-up electric heating system. The high limit must be manually reset thereafter to
restart the heater.
ManualReset
Surface Mounted High
TemperatureCut-OffSwitch Immersion HighTemperatureCut-OffSwitch

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SECTION II – INSTALLATION
WARNING / CAUTION
DO NOT TURN ON THE SOLAR WATER SUPPLY to this equipment until heater is completely
filled with water and all air has been released. If the heater is NOT filled with water when the power
is turned on, damage to the heating coil may result.
For protection against excessive pressures and temperatures, local codes require the installation of a
temperature-and-pressure (T&P) relief valve certified by a nationally recognized laboratory that
maintains periodic inspection of production of listed equipment of materials, as meeting the
requirements for Relief Valves and Automatic Gas Shutoff for Hot Water Supply Systems. ANSI
Z21.22-1971. THE CUSTOMER IS RESPONSIBLE TO PROTECT PROPERTY AND
PERSONNEL FROM HARM WHEN THE VALVE FUNCTIONS.
All water heaters have a risk of leakage at some unpredictable time. IT IS THE CUSTOMER'S
RESPONSIBILITY TO PROVIDE A CATCH PAN OR OTHER ADEQUATE MEANS, SO THAT
THE RESULTANT FLOW OF WATER WILL NOT DAMAGE FURNISHINGS OR PROPERTY.
WATER HEATER PLACEMENT
1. Place the heater on a solid foundation in a clean, dry location nearest to the point of most
frequent hot water use.
2. The water heater should be protected from freezing and waterlines insulated to reduce energy
and water waste.
3. Leave a minimum of 18” clearance for heating coil withdrawal, if necessary.
INSTALL THE HEAT EXCHANGER COIL
1. Remove the access panel. (See diagram below).
2. Insert the heat exchanger and align the holes in the cover plate with the slotted holes in the
flange. (Note: align heat exchanger pipe connections with the opening in the access panel.)
3. WARNING: THE NYLON BUSHINGS MUST BE IN THE OPENINGS BEFORE THE
BOLTS ARE INSERTED. FAILURE TO DO THIS WILL VOID THE WARRANTY.
4. Insert and secure the bolts to the nuts one at a time in the following manner.
a. Place the nut behind the slotted flange opening.
b. Hold the nut in place with one hand – insert the bolt with the other.
c. Thread the bolt into the nut and tighten.
d. Proceed to the next opening.
e. NOTE: BE SURE TO PLACE BOLTS IN ALL OF THE OPENINGS.

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PIPING INSTALLATION
NOTE: The most effective means for preventing deterioration from accelerated corrosion due to
galvanic and stray current is the installation of dielectric fittings/unions. The installation of these
fittings is the responsibility of the installing contractor.
1. All integral components have been properly sized to meet design conditions. Piping to the
unit should be sized to meet the design conditions, as dictated by good engineering practices.
2. Connect solar water supply and return lines to heating coil assembly.
3. Connect the cold water inlet and hot water outlet to the appropriate connections as shown;
refer to the drawing for location and sizes.
4. Install the combination temperature and pressure safety relief valve in the tapping provided.
Note that this is required by law for safety considerations.

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Outlet to floor drain Install into provided tapping
Manual Release
Lever
Temperature Probe
Temperature and Pressure Relief Valve
5. Install a relief valve overflow pipe to a nearby floor drain. CAUTION: No valve of any type
should be installed between the relief valve and tank or in the drain line.
ELECTRICAL INSTALLATION
1. Connect thermistor to thermistor clip.
2. If supplied with a back-up electric heating element; enter electric junction box with properly
sized feeder leads. Be sure to properly ground the water heater.
3. All other electrical connections are made at the factory; therefore, no other electrical
connections are necessary.
FILLING THE HEATER
1. Completely close the drain valve.
2. Open the highest hot water faucet to allow all air to escape from piping.
3. Open the valve to the cold water inlet and allow the heater and piping system to completely
fill, as indicated by a steady flow of water from the open faucet.
FINAL CHECKS
1. Check all connections for tightness.
2. Ensure that all the above steps are completed
3. After the water is heated for the first time, monitor the water temperature as described in
Section III, Quarterly Inspection.

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SECTION III - SCHEDULED MAINTENANCE AND OPERATION
WARNING / CAUTION
Before performing any maintenance procedure, make certain solar water and electric supply is OFF
and cannot accidentally be turned on.
MAINTENANCE AND OPERATION
The water heater is automatic in its operation. It will maintain a full tank of water at the temperature
setting of the thermostat. The water heater should not be turned on without first making sure that the
tank is full of water and that all air has been released.
FREEZING
The tank should be fully drained in the event the solar water supply water has been turned off and if
there is danger of freezing.
QUARTERLY INSPECTION
1. Monitor thermostat
a. Let water heater completely heat to a designated thermostat setting.
b. After thermostat satisfies (that is, when the thermostat actually clicks off), draw water from
heater.
c. Compare water temperature of drawn water to the temperature setting of the thermostat when
it satisfies. Normal variation between the two points is approximately + 5°F.
d. If these two readings do not coincide within acceptable tolerances and verification has been
made of the accuracy of the temperature-reading gauge, replace the thermostat.
2. Lift test lever on relief valve and let water run through valve for a period of approximately 10
seconds. This will help flush away any sediment that might build up in water passageways.
3. Inspect heating coil flange for leakage as follows:
a. Remove heating coil housing cover.
b. Visually inspect heating coil gasket for evidence of leaks.
c. Rub finger around gasket that is between the heating coil and tank flange for any evidence of
moisture. If moisture is present or a water drip is observed, follow procedure outlined in
Section V.
4. Check for loose electrical connections. Tighten as necessary.

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ANNUAL INSPECTION
1. Flush tank as follows
a. Shut off power supply.
b. Close valve on hot water outlet piping.
c. Open valve on drain piping.
d. Cold water inlet line pressure will be strong enough to flush sediment from the bottom of the
tank out through the drain. Let water run for 3-4 minutes.
e. Close drain valve.
f. Open hot water valve.
g. Turn power supply ON.
2. Units subject to exterior fouling or scaling should be cleaned periodically. A marked increase in
pressure drop and/or reduction in performance usually indicates cleaning is necessary.
3. To clean the outside of the tubes, remove the heating coil and use either of the following
methods.
a. Spray heating coil with water hose.
b. Consult with manufacturers of cleaning compounds and chemicals. They will check the
nature of the deposit, recommend the right cleaning compound, and in many cases provide
equipment and personnel for a complete cleaning job.
4. Do not tighten bolts until gasket is properly seated.
5. When tightening bolts in the element head, tighten the bolts in a criss-cross pattern. This will
evenly distribute pressure around the flange, and help prevent warping.

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SECTION IV – TROUBLESHOOTING
SOLAR WATER SYSTEM
Symptom Probable Cause Corrective Action / Remedy
Tubes are fouled. Clean tubes per Section III, annual
scheduled maintenance.
Gradual loss of heating
capacity.
Excess silt in bottom of tank. Drain and flush tank per Section III ,
annual scheduled maintenance.
Ruptured tube(s) in heating
coil.
Remove / replace heating coil.
Thermostat needs adjusting. Adjust thermostat
Overheating.
Circulator not operating. Repair or replace per separate O&M.
Immediate loss of heating
capacity.
Blockage in return line. Clean blockage from return line.
High rate of flow beyond
design conditions.
Consult factory.Excessive vibration.
Under sized piping to the
unit.
Re-pipe lines to unit using proper
sized lines.
Undersized return lines. Re-pipe return line using proper sized
lines.
Water hammer.
Insufficient slope on return
lines causing backup.
Increase slope on return lines.
* Red symptom indicates that equipment should be shut down immediately and cause of malfunction
corrected before unit is re-started or serious damage may result.

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BACK-UP ELECTRCIAL HEATER SYSTEM (if supplied)
Symptom Probable Cause Corrective Action / Remedy
Circuit breaker tripped at source. Reset circuit breaker.
High limit switch tripped. Reset high limit switch.
Loose wires. Tighten wires. Torque screws per torque
chart included in Section VI.
Heating element inoperable. Check heating element operation by
clamping an Amprobe around each wire to
the element. The ampere reading should
agree with the nameplate ‘AMP’ figure.
Low line voltage. Have source electrical system checked by
an electrician.
No hot water
Faulty thermostat. Move thermostat dial through full range. A
definite ‘click’ should be heard. If not,
replace thermostat.
Faulty thermostat. Check thermostat adjustment. Monitor
thermostat as described in Section III,
Quarterly Inspection. Replace if necessary.
Heating element not working on
all phases
Check to see that heating element is
working on all phases, by checking the
resistance (ohms) value for each element
and comparing with expected rating.
Water temperature
below settings at all
times
Heater improperly sized Verify heater is properly sized for the flow
rate and temperature rise of your system.
Replace elements with proper size as
necessary.
Relief valve
discharges
continuously
Excessive temperature or
pressure in tank
Temperature and pressure relief valves are
made to operate if the water temperature
exceeds 210°F or water pressure exceeds
the pressure rating of the safety relief valve.
If trouble is excessive temperature, then
thermostat is not shutting off at the right
setting and thermostat must be replaced.

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SECTION V - SERVICING & REPLACEMENT OF PARTS
WARNING / CAUTION
Before servicing or replacing any part make sure to turn the power supply switch to the OFF position.
RELIEF VALVE
1. Disconnect power from unit.
2. Shut off incoming cold and solar water supply.
3. Lift test lever on relief valve to relieve pressure in tank.
4. Disconnect overflow piping.
5. Unscrew relief valve, remove assembly and replace with new one.
6. Connect overflow piping.
7. Turn on incoming water supply and check for leaks.
8. Turn safety switch to ON position.
Test Lever
Overflow Piping Outlet
Tank Connection
Temperature Probe

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HEATING COIL
1. Disconnect power from unit.
2. Shut off incoming cold and solar water supply.
3. Attach hose to drain connection.
4. Lift manual release lever on relief valve to let air into system or break union on outgoing
water line.
5. Drain water from tank.
6. Remove access cover. (See diagram on page 9).
7. Disconnect supply and return lines from heating coil.
8. Remove bolts securing the heating coil to the tank flange.
9. Withdraw heating coil assembly.
10. Install insert new heating coil assembly per installation instructions on page 8.
11. Reconnect supply and return lines to heating coil.
12. Fill tank and check around gasket for any leaks.
SURFACE TEMPERATURE HIGH LIMIT CUT-OFF (if supplied)
1. Disconnect power from unit.
2. Remove access cover.
3. Disconnect the four (4) 14 gauge wires or three (3) 14 gauge wires and a jumper, as required.
Control Wires
4. Remove the two (2) mounting screws or disconnect from thermostat, as required.
5. Replace control and install new high limit switch by performing above steps in reverse order.
Mounting Screws

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HEATING ELEMENT (if supplied)
1. Disconnect power from unit.
2. Shut off incoming water supply.
3. Attach hose to drain connection.
4. Lift manual release lever on relief valve to let air into system or break union on outgoing
water line.
5. Drain water from tank.
6. Disconnect the wires from the heating element terminals.
Tank Flange
Wires
7. Remove the 3/8-16 nuts.
8. Withdraw element assembly and remove gasket.
Gasket
Element Assembly
Nuts
9. Install new gasket and insert new heating element.
10. Rewire element according to type of unit as shown below.
11. Fill tank and check around gasket for any leaks.

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2
L1 L2 L3
L1 L2
Single Element Operation
3ØOpenDeltaWiringforSimultaneousOperation
4
3
2
1
1
2
1
2
3
4
1
1 3
4
2
1
2

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L1 L2 L1 L2
Interlocked for Non-Simultaneous Operation Non-Interlocked for Simultaneous Operation
1
1
1
1
2
2
2
2
3 3
4 4
4 4
1 1
2 2

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SURFACE MOUNTED THERMOSTAT (if supplied)
1. Disconnect power from unit.
2. Remove access cover and locate thermostat.
3. Disconnect the two (2) or three (3) 14 gauge wires and jumpers, as required.
Control Wires
4. Remove two (2) mounting screws and disconnect from high limit cut-off, if required.
Mounting Screws
5. Replace thermostat using the reverse procedure.