NTI WF200 Installation And Operation Manual page 13

WF200
Control Sequence for Oil Add-on:
1. Standby ( T T Open, No Wood Fire ) – Oil boiler operates as normal.
2. Standby ( T T Open, Wood Fire) – When the temperature in wood boiler rises to the set point of the
L4006B control, the wood circulator is energized (pumping wood boiler water into the existing oil boiler),
and power is energized to the switching relay Pn. 81313. This will interrupt power to the burner through the
"Normally closed" contacts in the relay.
3. Domestic Coil (T T Open) – If there is a call for domestic hot water, the oil boiler will remain OFF unless
the temperature drops below the L4006B setting.
4. Call For Heat (T T Closed Wood Fire) – When there is a call for heat, the oil boiler operates normally. If
the temperature of the wood boiler is higher than the setpoint of the L4006B, the burner will be prevented
from operating (normally closed contacts of switching relay, Pn. 81313). The wood circulator is energized
pumping the wood boiler water into the existing oil boiler and into the house.
5. Call For Heat (T T Closed, No Wood Fire) – Oil boiler operates as normal.
6. Wood Boiler Exceeds L4081A LOW Limit Setting (200F) – Power to the Damper Motor (M) is
removed, thereby closing the wood boiler dampers and reducing the flow of combustion air to the flame.
7. Wood Boiler Exceeds L4081A HI Limit Setting (220°F) – In addition to cutting power to the Damper
Motor, power to the Dump Zone Valve (H) is also removed, thereby opening the normally open Dump
Zone Valve – causing its end-switch to close - which energizes TT of the oil boiler Aquastat. The Oil
boiler Aquastat then initiates the Heating Circulator, forcing water circulation through the Dump Zone.
8. Power Failure – Wood boiler dampers closes and the Dump Zone Valve opens; water will flow by gravity
around the dump zone loop. NOTICE: the Dump Zone should be the largest zone in the house.
Add wood according to the temperature outside. Overfilling will make the dampers close
for extended periods of time creating creosote in the chimney.
Installation and Operation Manual
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