PLUS Line Instruction Manual Supplement
PLUS & 
PLUS WATER HEATERS WITH 
4 Start-up (continued)
[3180] (burner on, space heating) Once flame is proven and stable, the burner turns down to low fire for approximately 2 minutes.
•After this low fire period, the burner is allowed to modulate. Firing rate depends on actual outlet water temperature versus target temperature.
5.Allow boiler to bring water temperature to target temperature.
[6180] (target temperature reached) The burner will shut down. The blower will run in postpurge (see below), then turn off. The boiler circulator continues to run as long as there is a call for heat.
6.Lower room thermostat to stop call for heat.
[1180] (postpurge) When the room thermostat is satisfied (call for heat ended), the burner turns off. The blower will continue for a
[0180] (no call for heat) Boiler is now in standby mode (waiting for heat call).
7.Repeat above steps several times to verify operation.
8.Return the room thermostat to normal setting.
Verify operation — PLUS water heater
1.Reconnect PLUS aquastat wiring to boiler if necessary.
2.Turn off power to boiler at service switch.
3.Wait a few seconds, then turn on power to boiler.
[A180]
4.Raise PLUS aquastat above tank temperature, to call for heat.
[5180] (blower/circulator on) The blower and PLUS circulator energize and the control checks for air flow.
[1180] (prepurge) Blower speed will increase to ignition speed. The blower will run in prepurge for 10 seconds.
[2180] (ignition) After prepurge, the control module opens the gas valve and starts ignition spark.
a.If burner flame proves within 4.5 seconds, burner continues to fire. Burner will fire at
— 50% of maximum input — for about 10 seconds to allow flame to stabilize.
b.If burner flame does not prove within 4.5 seconds, control module attempts ignition sequence again. Flame must prove within 5 attempts or control will lockout (display will show [E 02]).
c.Verify flame failure operation by closing boiler manual gas valve to prevent gas flow. Open gas
cock after testing.
[4180] (burner on, PLUS) Once flame is proven and stable, the burner is allowed to modulate. Firing rate depends on actual outlet water temperature versus target temperature.
5.Allow boiler to bring water temperature to target temperature.
[6180] (target temperature reached) The burner will shut down. The blower will run in postpurge (see below), then turn off. The PLUS circulator continues to run as long as there is a call for PLUS heating.
6.Lower PLUS aquastat to stop call for heat.
[1180] (postpurge) When the room thermostat is satisfied (call for heat ended), the burner turns off. The blower will continue for a
[8180] (PLUS circulator
[0180] (no call for heat) Boiler is now in standby mode (waiting for heat call).
7.Repeat above steps several times to verify operation.
8.Return the PLUS aquastat to normal setting.
Operating information
1.To check operating conditions (actual and target temperatures, for example), see page 40 in Ultra Boiler Manual for an explanation of the Ultra control module Information mode.
2.During normal operation (no shutdown or lockout), the right 3 display digits show actual boiler outlet water temperature.
Replace boiler jacket front door
Replace boiler jacket front door after installation or servicing. The boiler front door must be securely fastened to the boiler to prevent boiler from drawing air from inside the boiler room. This is particularly important if the boiler is located in the same room as other appliances. Failure to keep the door securely fastened could result in severe personal injury or death.
12 | Part number IWHA016A/1103 |
