Detroit Radiant Products Company MP Series - Manual (Page 20)

20
MP Series 3.0 Operation • Sequence of Operation • Diagnostics
Shut-down:
When the thermostat is satisfied, the TP-3250 will de-energize the 120VAC power to the common side of
the pressure switch, de-energizing the thermostat circuit on the TP-351A . The blower motor will continue
to cycle for a period of 2 minutes for a post-purge cycle .
NOTE: Due to the PID Controller optimizing the output of the heater, the unit may run for a short period
after the call for heat has been satisfied .
For extended shut down periods:
1 Set external controller devices to off or lowest setting .
2 Turn OFF the 120VAC to the heater .
3 Turn OFF the manual shut-off valve in the heater’s gas supply line .
4 Prior to start up after seasonal extended shut-down, an inspection of the heater must be performed by
trained gas installation and service personnel . This will ensure optimal operation and years of trouble-
free service .
Diagnostics
Lockout:
The controls will automatically lockout the heater system when an external or system fault occurs . There
are two types of lockout:
Soft Lockout: The heater will attempt to light three times . In the event of a failed ignition, (gas pressure,
valve, no flame sense etc .), the heater will enter a soft lockout period for 15 minutes and
then attempt to light three more times before entering a Hard Lockout mode .
Hard Lockout: If proof of flame is not established, a component failure occurs or blockages are evident,
the heater will enter hard lockout . If lockout occurs, the control can be reset by briefly
interrupting the power source . The control will not open the gas valve unless there is an
interruption by the user .
Figure 3.1 • Operational Indicator Lights (see Charts 3 .1 through 3 .3 for Operation & Diagnostic LEDs)
NEUTRAL EARTH
HOT
- 120V HEATER INPUT -
120V
Amber Light (120V)
Indicates Pressure
Switch Actuation
Amber Light (24V)
Indicates Gas Valve
Operation