DIAL SETTINGS
When using this control as an exact replacement, use same dial settings as for old control.
A.SETTING THE ROUND DIAL:
Set the round dial for “N” initially. This will enable minor additional adjustments to be made later if the specific instal- lation should require it (refer to “C”.)
B.SETTING THE SQUARE DIAL:
Select the proper square dial setting from table 1 or 2 below. For the majority of installations, the dial setting selected should provide satisfactory boiler operation without requiring any further dial adjustments. When required, additional adjustments may be made as explained in “C”.
OUTDOOR |
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DESIGN |
| SUGGESTED SQUARE DIAL SETTING | |||||
TEMPERATURE |
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20°F | 3 |
| 4.5 | ||||
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10°F | 2.5 |
| 3.5 | 5 | |||
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0°F | 2 |
| 3 | 4 | 5 | ||
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1.5 |
| 2.5 | 3.5 | 4.5 | 5 | ||
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1 |
| 2 | 3 | 4 | 4.5 | 5 | |
| 140 | 160 | 180 | 200 | 220 | 240 | |
| (60) | (71) | (82) | (93) | (104) | (116) | |
| BOILER DESIGN TEMPERATURE °F (°C) |
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SQUARE DIAL
Adjusts for
ROUND DIAL Adjusts comfort level required
Adjustment screw
for changing setting
of square dial
Table 2 shows suggested square dial settings for various reset ratios. The first number of the reset ratio refers to the outdoor bulb, the second number refers to the inside bulb. For
Reset Ratio | Suggested Square |
| Dial Setting |
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1.5 to 1 | 1 |
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1 to 1 | 2.5 |
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1 to 1.5 | 4.5 |
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C.ADDITIONAL ADJUSTMENTS:
If, due to system variables such as heat loss of building, boiler size, etc., the square dial setting selected in “B” does not give desired boiler temperatures, additional adjustments may be made as follows:
Round Dial – One division change in the round dial setting changes boiler water temperature about 5° at all outdoor temperatures.
Square Dial – Changing the square dial setting 1/2 division (3 full revolutions of adjusting screw) changes boiler water temperature about 10° at low outdoor temperatures (0° to
CONDITION | SUGGESTED ADJUSTMENT |
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Area too cool at low | Raise square dial setting. |
outdoor temperatures. |
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Area too warm at low | Lower square dial setting. |
outdoor temperatures. |
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Area too cool at all | Raise round dial setting. (Also |
outdoor temperatures | raise square dial setting if round |
| dial has been set to “warmest” |
| setting.) |
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Area too warm at all | Lower round dial setting. (Also |
outdoor temperatures | lower square dial setting if |
| necessary.) |
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