LAARS Mighty Therm AP (Sizes 500-1825) - Installation, Operation and Maintenance Instructions - Manual (Page 14)

LAARS Heating Systems
Page 14
3. To ensure that the spa inlet water does not exceed
104°F (40°C), the spa fi lter pump must circulate at
the minimum fl ow rates shown in Table 5.
Heater Model Minimum Filter Pump Flow Rate
500 220 GPM
600 270 GPM
715 320 GPM
850 380 GPM
Table 5 - Minimum Filter Pump Flow Rates For Spas.
Note: Maximum Spa Temperature Is
Assumed To Be 100°F (38°C).
The high limit stop should be changed to 140°F
(60°C). The set point should then be checked
following the procedure in Section 3.3.
5. Use the outlet valve “B” to set the inlet temperature
per Section 3.4.
6. Spas are excellent for relaxation, body-conditioning
and for arthritic and rheumatic problems, but
can be hazardous. The Consumer Product Safety
Commission has recommended the following
"Safety Rules for Hot Tubs:"
a. Spa or hot tub water temperature should
never exceed 104°F (40°C). A temperature of
100°F (38°C) is considered safe for a healthy
adult. Special caution is suggested for young
children.
b. Drinking of alcoholic beverages
before or during spa or hot tub use can
cause drowsiness which could lead to
unconsciousness and subsequently result in
drowning.
c. Pregnant women beware! Soaking in water
above 102°F (39°C) can cause fetal damage
during the fi rst three months of pregnancy
(resulting in the birth of a brain-damaged or
deformed child). Pregnant women should
stick to the 100°F (38°C) maximum rule.
d. Before entering the spa or hot tub, users
should check the water temperature with
an accurate thermometer; spa or hot tub
thermostats may err in regulating water
temperatures by as much as four degrees
Fahrenheit (2.2°C).
e. Persons with a medical history of heart
disease, circulatory problems, diabetes or
blood pressure problems should obtain their
physician's advice before using spas or hot
tubs.
f. Persons taking medications which
induce drowsiness, such as tranquilizers,
antihistamines or anticoagulants, should not
use spas or hot tubs.
3.7 Winter Operation
Complete
Shutdown
1. To shut down the heater for periods of several
months or more, turn manual main gas valve and
pilot gas valve to "OFF." Where danger of freezing
does not exist, some water should fl ow through the
heater during the normal fi lter cycle all year long,
even when the heater is turned off or shut down
completely, if all bypass valves are opened.
2. If the heater is not otherwise protected from
freezing temperatures, it should be completely
drained before the fi rst frost. Drain the heater by
removing the drain plug on the bottom of the front
header casting. Leave the plug out until ready to
use the heater again. Heater must be level to permit
adequate draining. When compressed air is used
to blow out lines, it is still necessary to follow the
above procedure. Keeping the pool heated and
the fi lter pump running continuously will not be
adequate protection. If there is a pump failure or an
electrical power failure, the heater cannot fi re and
may freeze and be damaged.
3. Improper Use of Heater: The Laars Pool Heating
Boiler is not designed for continuous use as an
"anti-freezing" device for pools. Operating the
heater with low water temperatures will cause the
fi ns on the heat exchanger to be partially blocked
with condensation. Incomplete combustion and
prolonged operation under these conditions will
result in the heat exchanger sooting up. This can
seriously damage the heater and may create a
dangerous fi re hazard.
3.8 Time Clock Operation
During the warm-up period, the heater must run
continuously so it can raise the pool temperature from
cold to above 70°F (21°C).
Remove all time clock stops and permit the heater to
raise pool temperature to 70°F (21°C) or above in one
continuous operation.
When the time clock stops are replaced, be sure to allow
the fi lter pump and the heater to stay on long enough to
keep the pool up to the desired temperature.
3.9 Therapeutic Pools (Spas)
Therapeutic pools or "spa" pools are usually piped and
controlled so that very warm or hot water, often with
air injection, is forced at high velocity into a confi ned
area of a swimming pool or into a small separate pool.
For the purposes of this manual, any application in
which the water temperature is maintained above 85°F
(30°C) is considered a spa. SPECIAL SET-UP AND
OPERATING PROCEDURES APPLY TO SPAS.
1. Models 1010I and 1010E and larger should not be
used for spas due to their higher temperature rises.
2. Since outlet temperatures can approach 140°F
(60°C) units must be piped in a Primary/Secondary
style similar to that shown in Figure 10.