Page 31
Cascading the FT Series ‘Heating Only’ Boiler
Domestic Hot Water Parameters
For a complete list of parameters, reference the FT Series Installation and Operation Manual 1342.
If a DHW aquastat is used, the maximum DHW load needs to be calculated to determine the number of boilers
required to meet max DHW load. The aquastat must be installed in the tank and wired to each boilers’ terminal
strip “DHW TEMP SENSOR” connection (page 10). They can be wired either in parallel (straight from the
aquastat to each boiler) or in series (aquastat to first boiler and then from boiler to boiler).
The DHW System Pump must be connected to the first boiler among those selected to handle the domestic
water load on the terminal strip labeled “DHW Pump” (page 10).
Domestic Hot Water Parameters
For a complete list of error codes reference the Mascot FT Installation and Operation Manual 1342
Index
Numbers
Parameter
Description
21: dH
Indirect Storage Tank
Temperature Set Point
Sets Maximum Indirect storage tank
Temperature Range: 95 - 180°F , Default 120 °F
22: dd
Indirect Storage Tank
Differential Set Point
DHW Differential Set Point Range: 5°F-30°F,
Default 7 °F
23: Pr
DHW Pump Post Run Time
DHW Pump Post Run Time Range: 0-10 Min,
Default 1 Min
24: dP
DHW Priority Timer
DHW Priority Timer Range: 0 – 60 Min , Default
30 Min
25: St
Boiler Set-point Temperature
for DHW Demand
Boiler Set-point Temperature for DHW Demand,
Range: 120 °F– 180 °F , Default 180 °F
ADD NEW ERROR SECTION
D. Typical Cascade Error Codes
For a complete list of error codes reference the Mascot FT Installation and Operation Manual 1342
Er:30
System Sensor Short
NOTE:
This error will only appear if the boiler is used in a cascaded system.
This Error Code will go away when system sensor is repaired or replaced.
1. Check system temperature sensor. Ensure connections are secure.
2. Check system sensor resistance. If resistance is zero, replace the sensor.
3. If the problem persists, replace the main control.
NOTE:
During the error state the units will continue to operate. Boiler setpoint
will be the same as the system sensor setpoint until the issue is remedied.
During normal operation boiler setpoint is defaulted to 20°F higher than the
system setpoint to a maximum of 180°F setting
Er:78
Cascade
Communication Error
NOTE:
This error will only appear in a cascaded system.
1. Turn power OFF and ON at the boiler display panel.
2. If error reappears, ensure all cascaded boilers are powered ON.
3. If error reappears, check Installer Mode parameter 28 at the Leader boiler.
Ensure the number of cascaded units chosen in this parameter matches the
number of cascaded units in the system.
4. If error reappears, check Installer Mode parameter 27 at all cascaded
boilers. Ensure the address number matches that of the connected boiler (00
for Leader, 01 for Follower 1, etc.) and that no numbers are skipped or
repeated.
5. Ensure every unit in the cascade system is connected properly. Inspect the
cascade cables and ensure all are connected without damage or defect.
Repair or replace any damaged cables.
6. If the problem persists, contact technical support.
5.D
Domestic Hot Water ‘Storage Mode’ for Cascade System
(continued)
Using a DHW Sensor (thermistor type)
When using a DHW sensor, the boiler monitors the temperature of the indirect water heater. Connect the
sensor to the “DHW Temp Sensor” terminals of the boiler piped to the indirect water heater. When using a
DHW sensor, Parameter # 39 (39:SA) must be set to “SEnS”. The temperature of the DHW in the indirect
water heater is determined by Parameter #21 (21:dh) in the table below. The sensor differential is determined
by parameter #22 (22:dd) in the table below. The boiler setpoint temperature during a DHW demand is
determined by Parameter #25 (25:st) in the table below. Connect the DHW Pump to the “DHW Pump” terminals
of the boiler piped to the indirect water heater. A relay is required if the DHW pump draws more than 2 amps.
Confirm the sensor is fully inserted in the tank well to ensure accurate temperature readings.
Table 3.
Index Parameters.
