Teledyne Laars Hi-E EPH 300 User manual

Page 1 Hi-E Model EPH Pool and Spa Heater
SECTION 1.
General Information
Thismanualprovidesmaintenanceinstructionsforthe
Teledyne Laars Hi-E Model EPH 300 pool and spa heater.
SECTION 2.
Overall Operation and Service
2A. Heater Control Components
Some of the heater control components are the same
as those used in conventional heaters, but others are
designed specifically for the Hi-E EPH 300 heater (see
Fig. 1).
The following paragraphs describe the special
controls and their operation.
2A-1. Pressure Switch
The pressure switch is a safety device that senses
water pressure or back pressure between the heater and
the pool or spa when the filter pump is operating. The
switch is factory set at 2 pounds per square inch (psi)
(14 kilopascals [kPa]).
When the switch senses adequate water pressure, it
closes, allowing the heater to fire. The switch opens any
time water pressure is below 2 psi (14 kPa) and remains
opens, preventing the heater from firing, regardless of
the temperature control setting. If the water pressure is
too high, the switch remains closed, allowing the
heater to fire even if the filter pump is off. Therefore,
the height difference between the heater and the pool or
spa water surface level must fall within the correct
range.
2A-2. High Limit Switches
The Hi-E heater has two disk-type high limit
switches to meet ANSI safety requirements. The high
limit switches open if the temperature of the water
exceeds the respective limits, shutting down the heater.
The high limit switches close and automatically reset
when exposed to cool water flow for a short time.
The 150 degrees Fahrenheit (°F) (66 degrees
Celsius [°C]) high limit switch senses the temperature
of the hottest water as it leaves the heat exchanger.
The 135°F (57°C) high limit switch senses the tem-
perature of the mixed water after it leaves the heater
and mixes with water that bypasses the heater inlet to
the outlet.
Water can overheat if the water flow rate drops,
usually due to a flow restriction in the heat exchanger,
pool piping system, or a dirty filter. A broken disc or
spring in the automatic flow control valve can cause
the 150°F (66°C) high limit switch to open, allowing
too much water to bypass the heat exchanger, corre-
spondingly lowering the water flow rate through the
heat exchanger.
Figure 1. Component Location

Page 2
2A-3. Fusible Link
This is a one-time, thermally fusible element which
shuts down the heater if it detects temperatures higher
than 305°F (152°C) inside the heater control compart-
ment.
2A-4. Temperature Control Panel
The temperature control panel includes two
temperature controls (regulates pool/spa water tem-
peratures) and a touch pad (OFF, SPA, and POOL)
that turns the heater on and off and selects which
temperature control will be active. An indicator light
above the controls tells you which is active. The
control panel also has lights labeled, WATER BELOW
TEMP, HEAT ON, and FAN ON. These lights indi-
cate the operating status of the heater.
2A-5. Venturi Pressure Switch
The venturi pressure switch senses pressure
through the venturi. Blockage in venting or the heat
exchanger will cause the venturi pressure switch not to
close. The venturi pressure switch is pre-set at the
factory for normal installations. Do not adjust the
venturi pressure switch.
2A-6. Ignition Control
The ignition control provides power to the igniter
and fan, opens the gas valve when there is a call for
heat, and senses when a flame is established. The
ignition control is programmed to make three attempts
at ignition. Each attempt consists of the following
cycle:
1. A 15-second purge period during which the
combustion fan purges the combustion chamber.
2. A 20 to 35-second igniter heat-up period. The
glow of the igniter can be seen through the heater
view port near the end of this period.
3. A 7-second trial for ignition. The gas valve opens
and gas ignites. The gas valve stays open as long
as the igniter senses flame.
If ignition is not successful, the control shuts down
and locks out. It remains in the lockout condition until
the heater is turned off then back on by the touch panel
pads or when the 120 volt alternating current (VAC)
power to the heater is interrupted.
2A-7. Gas Valve
The Hi-E heater has a negative pressure gas valve
that regulates the gas to the heater based on the
amount of air flow through the venturi. The gas valve
is the ON/OFF device that permits gas to flow from
the supply line into the heater. It is energized by the
ignitioncontrol.
2A-8. Transformer
The transformer converts 120VAC into 24VAC
used by the heater circuit.
2B. Venturi/Negative Pressure Regulator
System
The fuel/air mixing system in the Hi-E EPH 300
heater makes sure the fuel/air ratio remains the same
under a wide range of flow conditions (see Fig. 2).
An important feature of the pressure system is that
blockage of the combustion air supply or the vent will
only reduce the firing rate; it will not cause poor
quality combustion.
2C. Pressurized Combustion System
The Hi-E EPH 300 heater has a positive pressure
combustion system; the pressure in parts of the system
is slightly higher than atmospheric pressure. This has
an important effect on service procedures. There can
be NO gas leaks in the system from whatever cause. If
a leak exists in the section between the combustion fan
and the burner, a flammable mixture of fuel gas and
air can escape. A leak in the combustion chamber will
release very hot gases. These gases may enlarge the
leak due to their high temperature. Leakage from the
system at points after the heat exchanger will release
combustion products or condensate water. The service
technician must be alert to these possibilities when
servicing the heater.
WARNING
Improper installation or maintenance can
cause nausea or asphyxiation from carbon
monoxide in flue gases which could result in
severe injury, property damage, or death.
2D. Periodic Inspection
Before starting troubleshooting procedures,
inspect the pool or spa system for obvious problems.
All of the pool system components, including pump,

Page 3 Hi-E Model EPH Pool and Spa Heater
Figure 2. Venturi/Negative Pressure Regulator System
filters, and strainers, water valves, gas supply, electri-
cal power and time clocks, have an effect on heater
operation. The following basic checks should be
performed:
1. Is electrical power to the heater turned on?
2. Is there a time clock or other control in the system,
and is that control on?
3. Is the heater turned on at the touch panel? If it is,
the light over the active temperature control will
be lit.
4. Is the temperature control knob set high enough to
call for heat?
5. Is the gas supply turned on at all locations?
6. Is the heater’s combustion air filter clean?
7. Are all wiring connections solid?
8. Is the ignition control in lockout mode? Turn the
heater off and then back on at the touch panel to
restart the ignition sequence.
If all of these items have been checked, look for
less obvious problems (see Section 3, Troubleshoot-
ing).
2E. Temperature Rise Test Procedure
A temperature rise test confirms proper water flow
through the heater. Perform a temperature rise test as
follows:
1. Verify the heater is OFF. If it is necessary to turn
the heater off, push the OFF button at the touch
pad (see Fig. 3) and wait at least 3 minutes.
2. Turn the filter pump OFF.
3. Remove the 1/4 inch (6.35 millimeters [mm])
National Taper Pipe (NPT) plug located on the
inlet/outlet header (see Fig. 4) and replace it with a
Pete's plug.
4. Insert a pocket thermometer through the Pete's
plug into the header to a depth of about 5 inches
(127 mm).
Figure 3. Temperature Control

Page 4
If the temperature rise is outside the range indi-
cated, two possibilities arise:
1. Case 1: The temperature rise value is less than
18°F (10°C).
2. Case 2: The temperature rise value is greater than
22°F (12.2°C).
2E-1. Temperature Rise Test Case 1
There are two conditions that can produce a
temperature rise value less than 18°F (10°C): The
supply gas pressure is too low or the system's water
flow is too high.
Use table 1 to verify the heater's gas supply while
the unit is firing and as close as possible to the unit
under test.
Low supply gas pressures can be the result of
using the wrong pipe size, meter, valves, or regulators.
Correct the problem, then repeat the temperature rise
test.If the temperature rise is still below 18°F (10°C)
after a retest, then the system's water flow may be too
high.
If the system filter-flow rate is higher than ap-
proximately 125 gallons per minute (GPM) (474 liters
per minute [LPM]), install a manual bypass valve with
an adjustable valve (see Fig. 5). Then repeat the
temperature rise test, gradually adjusting the flow with
the bypass valve (see Section 2D-3) until the proper
temperature rise is obtained. Once the adjustment is
complete, wire the handle of the manual by-pass to the
pipe to prevent any accidental change in the water
flow.
2E-2. Temperature Rise Test Case 2
The main reason for a temperature rise value
greater than 22°F (12.2°C) is a low water flow
through the heater. Check the installation for the
following:
1. Incorrect water pipe size or a combination of
different pipe sizes.
2. Excessive pipe length for the size pump installed.
3. Pump too small for application.
Figure 4. Thermometer Location
5. Make sure the pool filter is clean.
6. Close manual bypass valve, if installed.
7. Turn the filter pump ON and wait 5 minutes.
8. Record the temperature indicated by the thermom-
eter (cold water).
9. Turn the heater on following the lighting instruc-
tions found under the top panel of the heater.
10. Allow the heater to run for 5 minutes. Record the
new temperature reading (hot water).
11. Subtract the first temperature reading (cold water)
from the second temperature reading (hot water).
The difference between the two readings is called
the temperature rise. Proper water flow rate is
obtained when the temperature rise falls between
18 and 22°F (10 and 12.2°C).
12. If the temperature rise is within the correct range
(see step 11), complete the procedure as follows:
a. Turn the heater off.
b. Wait 5 minutes, then turn the filter pump off.
c. Remove the thermometer and the Pete's plug.
d. Replace the 1/4 inch (6.35 mm) NPT plug at
the header.
Table 1. Gas Supply Pressure Requirements
Supply Pressure Natural Gas Propane Gas
Water Column in. mm in. mm
Minimum 5 127 11 279
Maximum 10 254 14 356

Page 5 Hi-E Model EPH Pool and Spa Heater
SECTION 3.
Troubleshooting
3A. Supply Gas and Metering System
If the heater does not supply its rated output
(heating too slow), or if a blue lazy flame (too little
gas), or a bright flame (too much gas) is noticed,
check the supply gas pressure. Proper operation of the
fuel/air balancing system depends on the following:
1. Proper supply gas pressure to heater.
2. Correct gas pressure difference across the meter-
ing orifice.
3. Correct orifice for the fuel being used. Figure 3
shows how the system works.
4. Vent pipe length.
3A-1. Checking the Manifold Regulated Gas
Pressure
The Hi-E heater's negative pressure gas valve
regulates the gas to the heater based on the amount of
air flow through the venturi. Proper operation of the
heater depends on the proper settings of the gas flow.
Symptoms of improper operation are either a blue lazy
flame (too little gas) or a bright yellow flame (too
much gas).
Figure 5. Typical Manual Bypass Valve Installation
Notes:
1. When using metal pipe as heat sink, join metal and PVC/CPVC, using metal male and PVC/CPVC female connection.
2. A manual bypass valve is used only when filtration rate normally exceeds 125 GPM (474 LPM).
4. Too many restrictions in the water path which may
include small pumps or 2 speed pumps (low), dirty
filters, clogged pipes, or partially closed water
valves to the heater.
Verify and correct the condition and then repeat
the temperature rise test.
Caution
Operation with the temperature rise above
maximum or below the minimum can
damage the heater and will void the warranty.
2E-3. Adjusting the Manual Bypass Valve
After the manual bypass valve is installed, use the
following procedures to set the bypass valve:
1. Close the manual bypass valve completely.
2. Repeat steps 7 through 12 of the temperature rise
test (see Section 2E), slowly opening the manual
bypass until the temperature falls between 18 and
22°F (10 and 12.2°C).
3. Once the temperature is within the correct range,
wire the handle of the manual bypass valve to the
pipe to prevent change in the water flow.

Page 6
NOTE: Gas supply test, stack test, and air flow filter
test should be completed before attempting this test or
making any adjustments.
1. Check supply gas pressure (see Section 3B-2).
2. Check that all ports and tubes are clear that
connect the gas valve and venturi.
3. Check for proper orifice (see Table 2).
4. Attach a manometer or a 1/2 inch (13 mm)
negative pressure gauge between the outlet pres-
sure tap on the gas valve and the venturi (lower)
inlet pressure tap (see Fig. 6).
Figure 6. Checking the Gas Pressure
Table 2. Gas Metering Orifice Size
Natural Gas LP Gas
Orifice Diameter 0.354 in. 0.295 in.
(8.99 mm) (7.49 mm)
Color Code Brass Silver
5. The pressure at the gas valve outlet will be 0.2
inch (5.08 mm) water column (W.C.) less than the
pressure at the venturi (lower) inlet.
6. Take a reading. The ideal range should be between
-0.1 and -0.3 inches (-2.5 and -7.6 mm) W.C.
when the gas valve is energized.
IMPORTANT: Before the gas valve is energized, the
pressure reading will be approximately 2.8 inches (71
mm) W.C. on outdoor units fitted with the standard
vent stack. On indoor installations with vent piping as
long as 60 feet (18 meters [m]), the pressure can be as
low as 2.0 inches (51 mm) W.C.
3A-2. Checking the Supply Gas Pressure
To check the gas supply pressure:
1. Attach one end of a manometer hose to the fitting
on the gas valve (see Fig. 6).
2. Remove threaded cap from T-fitting and replace
with fitting from manometer.

Page 7 Hi-E Model EPH Pool and Spa Heater
3. A minimum of 5 inches (127 mm) W.C. for
natural gas and 11 inches (279 mm) W.C. for
propane gas, when the burner is firing, is required.
4. If the supply gas pressure is less than the mini-
mum, check for under-sized pipe between the
meter and the heater, a restrictive fitting, an under-
sized gas meter.
IMPORTANT: Any gas supply problem must be
corrected. The source of the incorrect supply pressure
must be found and corrected. If you cannot clear up
the supply pressure problem, contact a qualified
service technician or your local gas company.
3A-3. Checking the Metering Orifice
Gas flow is controlled by the orifice in the fitting
between the gas valve and the venturi throat. The
orifice must be the correct size for the fuel being used
(see Table 2).
To inspect the gas orifice:
1. Disconnect the venturi pressure tube (see Fig. 6).
2. Carefully remove the fitting between the gas valve
and the venturi throat.
3. Remove the orifice and inspect it.
4. Reassemble all parts properly after making sure the
orifice size is correct.
3A-4. Checking the Venturi Pressure Switch
The venturi pressure switch is calibrated to open
when the pressure falls below the minimum values,
shutting off the heater. If a dull blue lazy flame is
detected or it takes a long time for the heater to heat
up, the cause may be:
1. A restriction in the combustion system flow by a
partially blocked combustion air inlet or vent
terminal.
2. Excessive vent pipe length or too many 90 degree
elbows (see Document 3090B, Installation and
Operation Manual).
3. Worn or dirty combustion air filter.
4. Internal blockage in the condensate trap or drain
system.
To check the venturi pressure difference perform
the following stack test:
1. Remove upper inlet pressure tap from the top of
the venturi (see Fig. 6).
2. Attach the hose from the manometer to the upper
tap on the venturi.
NOTE: The manometer must be able to read a
negative pressure.
3. Start the heater and let the unit fire.
4. Take a reading. Readings should be:
a. -2.2 to -3.2 inches (-56 to -81 mm) W.C. for
outdoor units with standard stack extensions.
b. - 1.4 to -3.2 inches (-36 to -81 mm) W.C. for
indoor units with proper venting.
3A-5. Checking the Air Flow (Filter)
The amount of gas that flows to the burner is
regulated by the amount of air through the venturi.
Testing pressure readings at the gas valve pressure tap
can determine if there is an air flow problem.
If the heater is heating slowly or cycling on and
off, perform the following filter test:
1. Attach a manometer or a negative pressure gauge
to the press tap opening on the gas valve.
2. Turn on the heater.
NOTE: The fan will come on and the heater will fire
about 20 to 30 seconds later.
3. Take a reading. Reading should be -0.3 to -0.5
inches (-7.6 to -12.7 mm) W.C.
4. If the reading is less than -0.3 inches (-7.6 mm)
W.C., check the tubing between the gas valve
regulator and the venturi port for blockage.
5. If the reading is greater than -0.5 inches (-12.7
mm) W.C., there is a restriction of air through the
heater. This will not harm the heater, only reduce
its output British Thermal Unit (BTU) rating.
To correct the reduced air flow check the following:

Page 8
1. Check and clean the air filter. It may be necessary
to replace, if very dirty.
2. Check for excessive pipe length on vent.
3. Check for a dirty or worn fan unit.
4. Check to see if the “P” trap is clear.
WARNING
Do not attempt to adjust the gas pressure at
the gas valve. Serious damage could occur.
3B. Electrical Troubleshooting
This section describes procedures for checking the
electrical power and control components of the heater
(see Fig. 7 for a typical example of a wiring diagram).
Use the flowchart (see Fig. 8) and the following
sections to troubleshoot the heater. Read all of these
procedures before starting repairs.
The following tools are required for proper service
and problem diagnosis of the heater and heater system:
1. Gas pressure test kit with range from 0 to 14
inches (0 to 356 mm) W.C.
2. Electric meter(s) with the following ranges:
a. 0 to 150 volts alternating current (VAC)
b. 0 to 25V direct current (DC)
c. 0 to 2,000 ohms resistance
3. A pressure gauge and a thermometer with proper
ranges for heater operation.
3B-1. Testing the Electrical Supply Power
The electrical components of the Hi-E heater
operate with supply voltage ranging from 103 to
126VAC at 60 Hertz (Hz). To test the electrical power
supply:
1. Measure the voltage at the hot and neutral wirenut
connections in the heater electrical junction box.
2. Voltage outside of the required range may be due
to poor wiring connections, to other loads (e.g., air
conditioning compressors), or to an electrical
utility company problem.
3B-2. Testing the Pressure Switch
All new heaters are provided with pressure
switches preset to work at an optimum elevation of 3
feet (0.91 m) above or below the water surface level of
the pool/spa to be heated (see Fig. 9). However, the
switch can be adjusted to operate correctly in heaters
installed a maximum of 10 feet (3.05 m) below the
water surface of the pool/spa and to a maximum of 6
feet (1.83 m) above the water surface.
NOTE:
Pressure switches are only adjusted to turn
heater off, not on.
•DO NOT adjust the pressure switch if the heater is
installed at elevations of more than 6 feet (1.83 m)
above the water surface or more than 10 feet (3.05
m) below the water surface. Instead, contact your
Teledyne Laars representative for instructions.
If it is known positively that too much water
pressure is preventing the switch from opening and
turning the heater off, adjust the pressure switch (see
Sections 3B-5). If the heater is installed within the
recommended range, but does not fire, perform the
following back pressure test to check the water pres-
sure switch:
1. Use a volt-ohmmeter and check the voltage at the
water pressure switch.
2. If voltage is found at one terminal and not the
other, the pressure switch is keeping the heater
from firing.
3. To further isolate the problem, remove the copper
tube from the pressure switch.
4. Attach a pressure gauge to the tube and turn on
the pump.
5. If the pressure gauge reads less than 2 psi (14
kPa), there is a pressure related problem. The
problem may be caused by low water pressure.
A drop in the water pressure may be caused by:
1. A very short pipe run from the heater to the pool
or spa may prevent sufficient back pressure from
developing and prevent the pressure switch from
closing. If this occurs, lengthen the piping between
the heater and the pool where the return line
enters, or install directional fittings or elbows.

Page 9 Hi-E Model EPH Pool and Spa Heater
Figure 7. Wiring Diagram
LEGEND
P - PURPLE BL - BLUE
BK - BLACK O - ORANGE
W - WHITE G-Y - GREEN W/ YELLOW TRACER
BR - BROWN W-BK - WHITE W/ BLACK TRACER
Y - YELLOW W-R - WHITE W/ RED TRACER
R - RED BL-O - BLUE W/ ORANGE TRACER
GY - GRAY
FACTORY WIRED 115V
FIELD WIRED 115V
FACTORY WIRED 24V

Page 10
Figure 8. Troubleshooting Flowchart
YES
1. Is pool pump on?
2. Is pool filter clean?
3. Are all pool valves open?
4. Perform back pressure test (see Section 3B-2).
1. Check high limit switches.
2. Check high limit switch wires.
3. Check Fireman's switch.
4. Perform temperature rise test (see Section 2E).
Check fuse.
NOTE: Blown fuse is sign of short or overload.
Do not bypass or jumper.
1. Check burner chamber seals.
2. Check for excessive heat in control area.
3. Replace fusible link.
Is WATER BELOW
TEMP light on? NO
24VAC at Transformer Secondary
24VAC at Pressure Switch Red Wire
24VAC at Pressure Switch Blue Wire
24VAC at Fusible Link Blue Wire
24VAC at Fusible Link Red Wire
Is Combustion Fan
Operating?
Table 3. Temp Control Sensor Resistance
Water Temperature Sensor Resistance
°F °C Ohms
50 10 19,906
60 16 15,314
70 21 11,884
80 27 9,299
90 32 7,333
100 38 5,827
NO
120VAC at Terminal
F2 on Ignition
Control?
120VAC at Terminal
F1 on Ignition
Control?
Check 120V wiring from
Power Supply.
Replace Ignition Control.
YES
Page 11
1. Verify supply voltage at transformer primary.
2. Check circuit breakers.
3. Check transformer wiring.
4. Replace transformer.
YES
YES
NO
YES
YES
YES
NO
NO
NO
NO
NO
NO
YES
YES
1. Turn temperature control up to call for heat.
2. Push proper POOL/SPA button.
3. Check temperature control sensor (see Table
3).
4. Check all wiring to temperature control
circuit board and touch panel.
Is FAN ON light on? NO
Check fan and fan
wiring. YES

Page 11 Hi-E Model EPH Pool and Spa Heater
1. Check fan operation
2. Check air flow through vent.
3. Check venturi pressure switch.
4. Check wire between fan switch and ignition control.
24VAC at TH Terminal on
Ignition Control
YES
Is Igniter Glowing? Replace Ignition Control
YES
YES
24VAC at Ignition Control VAL
Terminal?
NO
NO
Check Igniter Resistance
NO
120VAC at Igniter?
Replace Igniter
NONE
Replace Ignition Control
NO
Is Burner Firing? NO 1. Check supply gas and verify gas valves are open.
2. Verify 24V to gas valve (in none, check wires).
3. Replace gas valve.
YES
Figure 8. Troubleshooting Flowchart (Continued)
3. A filter pump with a bad motor or impeller
develops less pressure.
3B-3. Adjusting the Pressure Switch
When the heater is installed between 3 and 10 feet
(0.91 and 3.05 m) below the water surface of the pool
or spa, the pressure switch senses the increased weight
of the water, remains closed, and allows the heater to
fire when insufficient water is present. Adjust the
pressure switch as follows:
1. Turn heater to OFF position.
2. Disconnect wires to the pressure switch.
3. Clip leads of a voltmeter across the pressure
switch.
4. Set voltmeter to lowest resistance scale.
5. Use a 7/32 inch (5.55 mm) Allen wrench to adjust
the switch. Slowly turn the adjustment clockwise
(raising the setting) until the pump turns OFF (see
Fig. 10).
Figure 9. Optimum Elevation Between the Heater and
the Pool/SPA
2. A dirty or clogged pool filter or leaf trap may
restrict the water flow and cause pressure loss.
The dirtier the filter or trap, the greater the loss.

Page 12
To test the ignition control:
1. Turn the heater on and observe the ignition
sequence.
2. If the igniter doesn’t glow, turn the power off and
disconnect the igniter from the ignition control.
3. Connect the leads of the voltmeter to the igniter
and igniter/120 terminals of the ignition control.
4. Set the voltmeter on the AC scale with a range of
at least 150V.
5. Turn the heater on.
6. Turn the temperature control knob all the way to
the right. After about 15 seconds, the voltmeter
should read about 120V.
7. If the voltmeter does not read voltage, replace the
ignitioncontrol.
3B-5. Testing the Igniter
If there is proper voltage, but the igniter does not
glow, the igniter may be open. To test the igniter:
1. Switch the volt-ohmmeter to read resistance or
ohms, on a range which can read from zero to
about 500 ohms.
2. With the igniter unplugged from the ignition
control, connect the leads of the ohmmeter to the
ends of the igniter wiring (see Fig. 11). A cold
igniter should have resistance in the range of 50 to
400 ohms.
3. If the reading is above or below the range of 50 to
400 ohms, replace the igniter.
Figure 10. Adjusting the Pressure Switch
6. Turn pump ON. If pressure switch does not open,
turn pump OFF and repeat step 5. When pressure
switch opens, go to step 7.
7. Slowly turn the adjustment clockwise until the
pressure switch closes.
8. Then slowly turn the adjustment counterclockwise
until the pressure switch opens again.
9. Turn the pump OFF and ON to check the adjust-
ment. Pause after each attempt. The pressure
switch should open immediately after the pump
stops.
10. Reconnect wires to the pressure switch.
11. After pressure switch is adjusted, the rise should
be taken to verify water flow.
12. Turn the heater ON following the instructions
found on the inside of the heater.
13. Set the temperature control to the desired tempera-
ture.
14. If a satisfactory adjustment cannot be made,
contact a Teledyne Laars representative for
assistance.
3B-4. Testing the Ignition Control
Caution
The ignition control and igniter operate on
120V power. Keep this in mind while
servicing the heater, and take care to avoid
electrical shock. Figure 11. Igniter Resistance Test

Page 13 Hi-E Model EPH Pool and Spa Heater
4. Remove the foam sleeve and clean it with warm
water and detergent, if necessary.
5. Take out the paper element and shake or gently
brush the element to remove any dust that may
have collected. Compressed air may be used for
this process. If the paper element cannot be
cleaned satisfactorily, replace it.
Caution
When using compressed air, be careful not
to damage component or direct compressed
air at anyone. Failure to comply could result
in damage to component or injury from
flying dust.
6. Reinstall the paper element, the foam sleeve, and
the retaining hardware. Make sure the air filter is
seated tightly at the venturi inlet, and the cap is in
place so that air cannot bypass the filter element.
4B. Inspecting the Flow Control Valve
The flow control valve maintains the correct
volume of water through the heater over varying
conditions (e.g., water pressure and pool filter cleanli-
ness) up to a maximum flow rate of 125 GPM (474
LPM). If the system's filter flow rate exceeds 125
GPM (474 LPM), a bypass valve is required.
The flow control valve normally does not require
service, but chemical imbalances can damage the flow
control valve, shaft, or spring which, over time, can
slow or eventually shut down the valve. Either condi-
tion can cause erratic heater operation and shorten
heater life.
Perform a temperature rise test (see Section 2E) to
confirm proper operation of the flow control valve.
To inspect the flow control valve:
1. Turn OFF the filter pump.
2. Remove the cap from the flow control valve (see
Fig 13).
3. Inspect the disk to make sure it is properly seated.
4. If the disc is not properly seated, disassemble the
valve and overhaul it. Replace any corroded parts.
3B-6. Testing the Combustion Fan Motor
If the combustion fan will not run, the motor or
ignition control may be at fault. To test the combus-
tion fan:
1. If the FAN ON indicator light is on, and the fan is
not on, check for 120VAC at the motor.
2. If there is voltage, replace the combustion fan.
3. If there is no voltage, replace the ignition control.
3B-7. Testing the Gas Valve
If the igniter glows, but no flame appears at the
burner surface, test the gas valve as follows:
1. Clip one lead of the voltmeter to the gas valve
terminal having two brown wires attached to it.
2. If the voltmeter does not read voltage, replace the
ignitioncontrol.
WARNING
Never attempt to repair the gas valve. Such
attempts will void the warranty, and could
lead to dangerous results.
3. If the voltmeter shows voltage, verify that the gas
is on and the gas locks are open. If the gas is on
and the gas locks are open, then replace the gas
valve.
SECTION 4.
Maintenance
4A. Replacing the Combustion Air Filter
The Hi-E EPH 300 heater uses a high efficiency
paper, fiber matrix filter covered with a foam sleeve.
The sleeve stops large particles and extends the life of
the paper element. A dirty air filter can reduce the
combustion air so that the venturi pressure switch
does not sense enough air flow. If this occurs, replace
the combustion air filter as follows:
1. Remove the top of the heater.
2. Loosen the thumbnuts at the right end of the filter
assembly.
3. Remove the retainer and combustion air filter cap,
then remove the filter assembly (see Fig. 12).

Page 14
5. Disconnect the brown and yellow wires from the
gas valve.
6. Separate the four-wire connector located near the
combustion air fan (see Fig. 14).
7. Remove the four nuts and washers attaching the
combustion air fan to the top of the burner shroud.
8. Lift the entire venturi assembly off the burner
shroud and place it on a suitable work bench.
9. Remove the six nuts and washers attaching the
combustion air fan to the venturi.
10. Hold the combustion air fan with one hand, and
separate from the venturi.
11. Reverse the previous steps to install a new fan.
Figure 12. Filter Removal Figure 13. Flow Control Valve
4C. Removing the Venturi Assembly and
Combustion Air Fan
1. Turn off the electrical power and gas supply
outside the heater.
2. Remove the top panel.
3. Disconnect the supply gas pipe from the gas
valve.
Caution
Label all wires prior to disconnection.
Wiring errors can cause improper and
dangerous operation.
4. Disconnect all wires from the venturi pressure
switch.

Page 15 Hi-E Model EPH Pool and Spa Heater
Figure 14. Removing the 4-Wire Fan Connector Figure 15. Upper and Lower Front Panel Removal
4D. Replacing the Burner, Heat
Exchanger, and Condensate Pan
Due to the complexity of the procedures required
to replace these components, the instructions are
included in the replacement kits. The appropriate kit
numbers can be found in the parts list (see Section 5).
4E. Removing the Igniter
NOTE: One of the screws also attaches the ground
lug to the outside right panel.
1. Remove two retaining screws from the tempera-
ture control circuit board.
2. Carefully slide the temperature control circuit
board into the heater compartment.
3. On the right side of the heater, remove the three
screws that fastens the electrical junction box to
the right side panel.
4. Remove the upper front panel by removing the
screw located on the left side, inside the heater
compartment (see Fig. 15).
5. Lift the upper front panel out of the three slots and
set it aside (see Fig. 15).
6. Remove the lower front panel assembly by remov-
ing the three screws along the base of the heater,
and the four screws on the sides (see Fig. 15). Two
of these screws are inside the heater compartment.
7. Remove the hex bolts that fastens the igniter and
pull the igniter out of the heater. Make sure you do
not damage the refractory material around the
opening.
8. Install the new igniter so that the black igniter
surface doesn't touch the chassis or refractory
material when it is in place. The igniter should be
1/2 inch +1/16 inch (13 mm +1.58 mm) from the
burner surface and parallel to it (see Fig. 16).
Make sure there is no leakage from the combustion
chamber. A small leak of hot gas will erode the
leak area, make it larger, and cause a problem.
9. Install new gaskets.
10. If the igniter glows, but flame appears only briefly,
there may be a problem with the fuel supply,
igniter or ignition control, or the piping to the
ventingsystem.
11. If a new installation or the fuel gas piping has
been serviced, remove any air in the gas supply
line, so the heater will operate normally. Using an
incorrect fuel will result in the fuel/air mixture
being wrong and a flame that is not normal. The
fuel gas must be the same as specified on the
heater rating plate.

Page 16
Item Description Part Number
22. Burner/Heat Exchanger Assy................... R0204200
23. Bolt/Washer Set, Header ......................... R0205900
24. Header, Return......................................... R0202200
25. Gasket, Return Header............................ R0201200
26. Gasket, In/Out Header..............................R0201100
27. Header, In/Out ......................................... R0202600
28. Pressure Relief Pressure ......................... R0200000
29. Cover, High Limits ................................... R0201700
30. Retainer, High Limits ............................... R0207800
31. Harness Assembly, High Limits............... R0208000
32. High Limit, 150°F..................................... R0023000
33. High Limit, 135°F..................................... R0022700
34. Sensor Assy., Temperature...................... R0208100
35. Drain Cock/Plug Kit ................................. R0010500
36. Flow Control Assembly............................ R0208200
37. Disc, Flow Control ....................................R0011500
38. Spring, Compression, Green................... R0202000
39. Rod/Nut Set, Flow control ....................... R0206100
40. Gasket, Flow Control ................................R0011400
41. Cap, Flow Control.....................................10557400
42. Bolt/Washer Set, Flow Cntrl Cap ............ R0206000
43. Water Pressure Switch Assy. .................. R0200300
44. Water Pressure Switch ............................ R0095100
45. Siphon Loop, Water Press. Sw................ R0208300
46. Flange Assembly ..................................... R0055000
47. Bolt/Washer Set, Flange...........................R0211200
48. Flange, 2 Inches ....................................... 10573500
49. Sleeve, Flange , 2 Inches .........................S0078200
50. Gasket, 1-1/2 Inches Pipe Adapter ..........S0078100
51. Vent Stack Assembly............................... R0203100
52. Vent Adapter Assembly ........................... R0202800
53. Ignition Control ........................................ R0202900
54. Fusible Link.............................................. R0012200
55. Bracket, Ignition Control .......................... R0209100
56. Temperature Control Assembly ................R0211300
57. Knob/Temp-Lok Set ..................................R0211400
58. Label, Temperature Control ......................R0211600
59. 8-Pin Harness Assembly ......................... R0212300
60. 3-Pin Harness Assembly ......................... R0212400
61. Lug, Neutral ..............................................E0106800
62. Junction Box, Bottom .............................. R0209500
63. Junction Box, Top .................................... R0209600
64. Transformer, 120/24 VAC ........................ R0200800
65. Terminal Strip Assembly.......................... R0209700
66. Fuse Assembly ........................................ R0212600
67. Fuse, 1 1/4 Amp. ..................................... R0021300
68. Panel, Upper Front .................................. R0205100
69. Label, Upper Front Panel ........................ R0209800
70. Bezel, Temperature Control ..................... R0209900
71. Panel, Lower Front .................................. R0210000
72. Glass, Sight ..............................................F0038700
73. Panel, Upper Left Side............................. R0210100
74. Panel, Lower Left Side............................. R0210200
75. Panel, Top ................................................ R0210300
76. Panel, Rear .............................................. R0210400
77. Panel, Upper Right Side .......................... R0210500
78. Panel, Lower Right Side .......................... R0210700
79. Base Assembly ........................................ R0210800
80. Vent Termination* ..................................... 10685600
*Required for Indoor Installations
Figure 16. Igniter Installation
After eliminating all possible problems with the
fuel supply and igniter, replace the ignition control.
SECTION 5.
Parts List for Hi-E EPH 300
5A. General Information
To order or purchase parts for the Teledyne Laars
Hi-E EPH 300 pool and spa heater, contact your nearest
Teledyne Laars dealer or distributor. If they cannot
supply you with what you need, contact Customer
Service, Teledyne Laars, 6000 Condor Drive, Moorpark,
CA 93021, telephone [phone].
5B. Parts List
Item Description Part Number
1. Fan, Combustion ..................................... R0204700
2. O-Ring, Venturi ........................................ R0205400
3. Venturi...................................................... R0015700
4. Venturi Pressure Switch........................... R0203300
5. Tube, Venturi Press. Sw., Throat............. R0202300
6. Tube, Venturi Press. Sw., Filter ............... R0202500
7. Gasket, Combustion Fan......................... R0205500
8. Plug, Pressure Test Point ........................ R0204800
9. Nipple, Gas Orifice .................................. R0205600
10. Orifice
Natural Gas ............................................. R0205700
LP Gas ..................................................... R0205800
11. Valve, Gas ............................................... R0200100
12. Tube, Venturi Press. Sw., Valve............... R0202500
13. Filter Assembly ........................................ R0204500
14. Filter Support, Kit..................................... R0206200
15. Filter, Air................................................... R0201800
16. Harness, Combustion Fan....................... R0206700
17. Bracket, Gas Valve .................................. R0210900
18. View Port Nipple ...................................... R0201500
19. Igniter Assembly ...................................... R0016400
20. Gasket, Igniter ......................................... R0205300
21. Connector, Wire........................................E0092000

Page 17 Hi-E Model EPH Pool and Spa Heater

Page 18
H0141400A
q6000Condor Drive, Moorpark,CA 93021• [phone] FAX [phone]
q480 S.Service Road West,Oakville, Ontario, Canada L6K 2H4 • [phone] FAX [phone]
q20Industrial Way, Rochester, NH 03867• [phone] FAX [phone]
Litho in U.S.A. © Teledyne Laars 9602
TELEDYNE LAARS HI-E
LIMITED WARRANTY
Your Teledyne Laars Hi-E Model EPH 300 pool and spa heater is backed by this double
warranty to assure your complete satisfaction.
1. Controls, copper heat exchanger tubes, combustion fan, burner, and firebox panels
are warranted against defects in materials and workmanship for two (2) years from
date of purchase.
2. All other parts are warranted against defects in materials and workmanship for five
(5) years from date of purchase.
6000CondorDr.,Moorpark, CA 93021*[phone]
20IndustrialWay,Rochester,N.H.03867(603) 335-6300
480S.Service Road West,Oakville,Ontario,Canada L6K 2H4 [phone]
The above warranty applies only if the installa-
tion and operating instructions applicable to the
model purchased are expressly and completely
followed. These instructions are furnished with
the unit and are also available by writing to the
Teledyne Laars factory. The liability of Teledyne
Laars shall not exceed the repair or replacement
of defective parts, and shall not include transpor-
tation to or from factory, field labor, and consequen-
tial or incidental damages. Ship inoperative
parts or complete heater with Serial number, Model
number and purchase date, transportation prepaid,
directly to address below, attention Customer
Service.
Thiswarranty givesyou specificlegal rights.You may
also have other rights which vary from state to state.
Some states do not allow the exclusion or limitation
ofincidentalorconsequential damages,sotheabove
limitation or exclusion may not apply to you.
Printed on Recycled Paper
*