VHX SERIES STEAMER - ELECTRICAL OPERATION
F24700 (October 2001)Page 43 of 68
RELAY BOARD
Board Layout and LED Legend
The relay board Provides a central ized location for wire harness connections and power transf er through board
relays (K1-K7) to the other steamer contr ol s. Also, provides a condition or c om ponent troubleshooting indicator
by utilizing seventeen LED’S on the board to represent the status of the condition or c om ponent in the operating
sequence. When the condition f or t he component being monitored is satisf ied or activated, an LED will light to
indicate its proper operation. If the corresponding LED does not light then the condi tion or component has not
been satisfied or is not activ ated.
LED LEGEND
LED ON = Condition satisfied or component activated. 1 LED OFF = Condition not satisfied or component d e-activated.
LED DESCRIPTION LED DESCRIPTION
N1 Board powered (24vac). N10 Auxiliary water level satisfied (LLCO) and reset switch
activated.
N2 Auxiliary water level satisfied (LLCO). N11 Boiler operating pressure condition satisfied and reset
switch activated.
N3 High limit pressure switch c losed. N12 Combustion blower ON.
N4 S teamer is read y (ready light "green" is ON). N13 Com bustion bl ower air pres sure swit ch satis fied.
N5 Auxiliary water level satisfied (LLCO) and reset switch activated. N14 Ignition module pilot voltage (PV) to board level timing
circuit.
N6 1Low water condition exists (N2 LED ON) or previously ex isted. If
water level condition is satisfied and the reset switch is activated
then N6 LED will turn off.
N15 2Pilot voltage (PV) to pilot gas va lve.
N7 Boiler pressure condition satisfied and reset switch activated. N16 Ignition module main voltage (MV) to low water level
contacts (LLCO) on water board.
N8 1Boiler High pressure condition exists (N3 LED ON) or previously
existed. If boiler pressure condition is satisfied and the re set switch
is activated then N8 led will turn off.
N17 Low water level satisfied (LLCO) and main voltage (MV)
from ignition module is supplied to main gas valve.
N9 Cycling pressure switch CLOSED “call for heat”.
NOTES: 1. At initial power on, N6 & N8 led’s will be ON until conditions are satisfied and reset switch is activated.
NOTE: 2. Board level timing circuit energized and powers pilot ga s valve for approximately 15 seco nds then de-energizes.