Janfire NH Installation And Servicing Instructions page 8

The modulation power is used to achieve longer working periods, minimizing the number of starts and stops. The
settings should be made so that the burner rapidly reaches target water temperature, and so that burner power
will be sufficient to take sudden increase in power consumption. The settings should also be able to decrease
power levels fast enough when target temperature is reached so that a balance in power is achieved. The
settings should let the burner operate within 10 – 18°F (6-10°C) beyond the target temperature before it stops,
as this range is required to handle changes in power output.
Thermostat hysteresis is set in "Service menu 64 –Differential below target" and "Service menu 65 – Differential
above target". Default PID factors are P = 20,000%, I = 2,000% and D = 0%. These setting can be used in most
cases. If PID is inactivated, OFF in "service menu 66", the burner works with the nominal, start-up, power level. If
no PT-100 sensor is connected the service menus 64-70 will be hidden and the burner will be controlled by the
thermostat and work on nominal, start-up, power level if "External thermometer – YES" selected.
Outdoor temperature modulation
In order to modulate boiler water setpoint temperature, a second PT-100 sensor measuring outdoor temperature
must be connected. (Standard supplied with the burner.)
Outdoor temperature will control boiler water temperature as follows:
68°F (20°C) or higher outdoor temp: Boiler temperature is equal to 140°F (60°C).
-4°F outdoor temperature or below: Boiler temperature equal to 185°F (85°C).
This function is active only if "Outdoor temp controls, service menu 78" is set to "YES" and the "Extra input as",
at service menu 77 is set to "Outdoor".
The outdoor temperature is sampled every 5 or 10 minutes, "service menu 79" and an average value is
calculated. This value is compared with the last sample, and a new target temperature is set if value has
changed. Maximum allowed change for target value is 1.8°F (1°C) each sample period even if calculated change
is greater.
The factor set heating curve is defined by parameters 81 – 84. One defines beginning and end points of the
heating curve by listing 2 boiler water and corresponding outdoor temperatures. These 2 data points define the
heating curve. Refer to service menu points 81 – 84 for details.
Janfire NH Burner Service Installation Manual 4.16.09 - Technical specifications are subject to change without prior
notice.
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