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Legacy™ Model LRZM Pool/Spa Heater
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Installation and Operation Manual
For most installations, an external bypass valve
is not needed in the heater water piping. This is due
to the large size of the heater's internal bypass valve.
If the pump flow rate is known to exceed 470 lpm, an
external bypass may be needed to assure proper heater
operation.
Water flow should be confirmed upon start-up of
the heater and in most servicing situations. If the flow
is not normal, corrections must be made to the pool
system. Flow is evaluated by determining the water
temperature rise through the heat exchanger.
Before checking the temperature rise, make
sure that the pool filter is clean and that gas supply
and burner pressures are correct. If necessary, clean
all components of the filter system. Temperature rise
is measured in the return header of the Legacy. To
measure the temperature rise, turn off the filter pump
and remove the plastic plug protruding through the
cabinet on the return header side of the heater. See
Figure 27. With the plug removed, install the special
thread adapter and Pete’s Plug
®
fitting and insert a
pocket thermometer. A temperature rise measurement
kit is available through your Zodiac distributor. See
Section 12 of this manual for the correct kit number.
The internal bypass can be adjusted by means of
a screw on the right-hand side of the header. To adjust
the temperature rise to within the ranges specified in
Table 7, proceed as follows:
1. If the piping system has an external bypass valve,
close it.
2. Turn the heater control panel to OFF.
3. Start the filter pump.
4. After three (3) minutes, note and record the
thermometer reading. This is the pool water
temperature.
5. Start the heater by turning the controller to ON.
Allow the heater to operate for five (5) minutes
or more. Note and record the thermometer
reading. Subtract pool water temperature from
this reading. This difference is the temperature
rise. Refer to Table 6. If your measured tempera-
ture rise is within the range designated for your
heater, skip steps 6 through 8.
6. Locate the bypass adjustment screw on the right-
hand side of the header (see Figure 22). Loosen
the nut so that the screw can be adjusted. A slight
water leak past the nut may be expected. Turn the
screw counterclockwise to decrease the tempera-
ture rise, and clockwise to increase the tempera-
ture rise as needed to achieve the ranges in Table
6. After the adjustment, tighten the nut so that no
leaks occur.
7. If the temperature rise is too low and cannot be
raised by means of the adjustment screw, the
flow is in excess of 470 lpm. An external bypass
will need to be installed, or if one already exists,
open the external bypass valve gradually until the
temperature range in Table 6 is achieved.
8. If it was necessary to adjust the external bypass
as outlined in step 7, scribe a line on the bypass
shaft and case to mark the correct adjustment
position. Wire or remove the valve handle to
prevent tampering.
table 6. Water temperature rise and Flow rates
(Measured at return Header)
Model
Minimum
Temp Rise,
°C (°F)
Maximum
Temp Rise,
°C (°F)
Minimum
System Flow
lps (GPM)
125
4 (7)
5 (10)
1.9 (30)
175
6 (10)
7 (13)
1.9 (30)
250
9 (16)
11 (20)
1.9 (30)
325
11 (20)
14 (26)
1.9 (30)
400
13 (23)
16 (29)
1.9 (30)
In a system without external bypass, it may be
necessary to make changes. If temperature rise is too
low, a manual bypass must be installed. If tempera-
ture rise is too high, there is inadequate flow, possibly
requiring a change to the piping system or a larger
pump. Before proceeding with either remedy, verify
proper heater operation. Low gas input results in low
temperature rise and vice-versa. A problem with the
heater internal bypass assembly also affects measured
temperature rise.
section 12. replacement parts
12.1 ordering information
To order or purchase parts for the Legacy pool
and spa heater, contact your nearest Zodiac dealer or
distributor. See the Zodiac web site at www.Zodiac.
com for the nearest service center. If they cannot
supply you with what you need, contact Technical
Support at Zodiac, telephone (800) 822-7933.
note
To supply the correct part it is important that
you state the model number, serial number
and type of gas when applicable. This
information is on the rating plate inside the
heater.
The following pages contain a parts list, general
exploded view, and detailed exploded views to aid in
parts identification. Pleas refer to these pages when
ordering parts for your Legacy pool/spa heater.
Summary of Contents for Legacy LRZ
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