Service manual

ManualsBrandsCamus Hydronics ManualsBoilerDMC103

This mode is designed for hydronic heating.

Once a heat demand is present, the BTC 1 turns

on the appliance pump and modulates the boiler

to maintain the calculated outdoor reset target at

the boiler inlet sensor. Outdoor reset calculates

the boiler target temperature based on the

outdoor air temperature and reset ratio.

A heat demand is generated when a voltage

between 24VAC and 120VAC is applied across

CD (common demand) and Ht D (heat demand).

Once voltage is applied, the BTC 1 turns on the

Dem 1 segment in the display. If warm weather

shut down (WWSD) is activated, the WWSD

segment is lit.

If WWSD is not activated and the inlet sensor is

½ (half) of the differential below the calculated

BOIL TARGET, the BTC 1 then changes the

modulation output to the START modulation

setting and closes the Stage contacts (pins 15 &

16) to proceed to trial for ignition. The burner

remains at minimum modulation until the flame

is proved and then modulating output changes

the boiler output to maintain the calculated boiler

target temperature at the inlet sensor. If the inlet

sensor reaches ½ (half) of the differential above

the BOIL TARGET, the appliance is shut off.

The boiler pump continues to circulate until the

PUMP DELAY timer expires.

The water temperature is controlled based on a

calculated boiler target temperature. The boiler

start (BOIL START) temperature is pre-set to

F and the auto re-set limit is set to 210°F and

is fixed. In addition to the auto reset limit the

factory installs a manual re-set limit set to 250°F .

Figure 19: Mode 4 Piping & Electrical Layout

Mode 5: Outdoor Reset using System Sensor

This mode is designed for hydronic heating.

Once a heat demand is present, the BTC 1 turns

on the appliance pump and modulates the boiler

to maintain the calculated outdoor reset target at

the system sensor. Outdoor reset calculates the

boiler target temperature based on the outdoor

air temperature and reset ratio.

A heat demand is generated when a voltage

between 24VAC and 120VAC is applied across

CD (common demand) and Ht D (heat demand).

Once voltage is applied, the BTC 1 turns on the

Dem 1 segment in the display. If warm weather

shut down (WWSD) is activated, the WWSD

segment is lit.

If WWSD is not activated and the system sensor

is ½ (half) of the differential below the calculated

BOIL TARGET, the control then changes the

modulation output to the START modulation

setting and closes the Stage contacts (pins 15

&16) to proceed to trial for ignition. The burner

remains at minimum modulation until the flame

is proved and then the modulating output

changes the boiler output to maintain the

calculated boiler target temperature at the

system sensor. If the system sensor reaches ½

(half) of the differential above the BOIL

TARGET, the appliance is shut off. The

appliance pump continues to circulate until the

PUMP DELAY timer expires. In this case, it is

imperative that the system pump operates

continuously in order to provide constant

circulation past the system sensor.