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After a setting has been chosen for the tank
temperature control, set the heater temperature control
10°F (6°C) higher. The heater's temperature control
senses the inlet water temperature to the heater. The
heater's manual reset high limit (and automatic
reset high limit, if applicable) senses heater outlet
temperature.
If the unit is equipped with an automatic reset
high limit, set the automatic reset high limit 20°F
(11°C) above the outlet temperature to avoid nuisance
lockouts. Set the manual reset high limit 5°F (3°C)
above the automatic reset high limit.
For units that only have a manual reset high limit
(no automatic reset high limit), set the manual reset
high limit 20°F (11°C) above the outlet temperature to
avoid nuisance lockouts.
Example, Imperial units: If the tank temperature
is set to 140°F, set the heater's temperature control to
150°F (140°F + 10°F). Further, if the temperature rise
through the heater is 25°F, the outlet temperature will
be 175°F (150°F + 25°F). Therefore, set the automatic
reset high limit to 195°F (170°F + 20°F), and the
manual reset high limit to 200°F (195°F + 5°F).
Example, Metric units: If the tank temperature
is set to 60°C, set the heater's temperature control to
66°C (60°C + 6°C). Further, if the temperature rise
through the heater is 15°C, the outlet temperature will
be 81°C (66°C + 15°C). Therefore, set the automatic
reset high limit to 92°C (81°C + 11°C), and the
manual reset high limit to 95°C (92°C + 3°C).
3.3.2. Internal Water Heater Temperature
Control:
When an external control is not used, the
circulator between the heater and the storage tank
must run continuously, so that the heater's temperature
control can detect and control the water temperature
in the storage tank. The water heater's temperature
control is adjusted to its lowest temperature position
(130°F, 54°C) when shipped from the factory. This is
the preferred starting point for setting the temperature
control.
If the unit is equipped with an automatic reset
high limit, set the automatic reset high limit 20°F
(11°C) above the outlet temperature to avoid nuisance
lockouts. Set the manual reset high limit 5°F (3°C)
above the automatic reset high limit.
For units that only have a manual reset high limit
(no automatic reset high limit), set the manual reset
high limit 20°F (11°C) above the outlet temperature to
avoid nuisance lockouts.
Example, Imperial units: If the heater's
temperature control is set to 130°F, and the
temperature rise through the heater is 25°F, the outlet
temperature will be 155°F (130°F + 25°F). Set the
automatic reset high limit to 175°F (155°F + 20°F) and
set the manual reset high limit to 180°F (175°F + 5°F).
Example, Metric units: If the heater's
temperature control is set to 55°C, and the
temperature rise through the heater is 14°C, the outlet
temperature will be 69°C (55°C + 14°C). Set the
automatic reset high limit to 80°C (69°C + 11°C) and
set the manual reset high limit to 83°C (80°C + 3°C).
3.4 Adjustment for Minimum Input Rate
(models with modulating gas valve)
Adjust the red knob on the modulating gas valve
to the dial number for the desired water temperature
(see Table 7). Adjusting the red knob to number
"1" sets the gas flow rate to minimum. The control
is factory set at "2" which is satisfactory for most
installations.
Dial No.
1
2
3
4
5
6
7
8
9
Table 7. Water Temperature Setting.
3.5 Hi-Limit Switch Checkout
After running the heater for a long enough
period, bring the water temperature within the range of
the hi-limit switch and slowly back off the high limit
setting until the heater shuts off. The main burners
should reignite when the hi-limit switch is reset and
turned back up to its original setting. The heater should
now run until it shuts off automatically on operating
control.
Should overheating occur or the gas supply fail
to shut off, turn off the manual gas control valve to the
heater.
3.6 Shut-Down Procedure
Shut down the heater following the instructions
found on the inside of the heater.
Where there is a danger of freezing, shut off the
water supply and remove the drain plugs on both sides
of the heater jacket. Drain every part of the system
subject to damage from freezing temperatures.
BRADFORD WHITE
Temp.
°F
°C
120
49
127
53
135
57
142
61
150
66
157
69
165
74
172
78
180
82
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