Harman Stove Company DVC500-C Manual page 30

DVC-500 Firebox Static Pressure Safety Protocol
General Causes And/Or Reasons For
Shutdown:
The DVC-500 operates with a negative pressure
firebox as a safety feature. Any loss of this
negative pressure will start the safety protocol,
( A two blink status warning )
Most safety status warnings may and or should
only occur during highest heat output settings.
The following list of potential reasons for warn-
ings is in order of most likely to least likely to
occur:
1. Opening the viewing door or the ash door for
long periods of time without turning control to
ASH OUT position ( ASH Out on feed adjuster
knob).
2. Blocked or partially blocked flue pipe. This is
generally a slow buildup and may only cause the
unit to go in and out of Stage 1. Although as the
condition gets worse the unit will continue to
step down until it goes out.
3. Draft motor fan blades dirty. This is generally
a slow buildup and may only cause the unit to
go in and out of Stage 1. Although as the condi-
tion gets worse the unit will Continue to step
down until it goes out.
4. Draft motor intake cover plate not installed or
not in proper position.
5. Gasketing problems with the viewing or ash
door.
6. Grate clean-out cover not closed properly,
Fig.26.
7. Grate inserts are extremely loose or out of
alignment, fig. 30.
8. Coal ash building up behind the ash pan to a
point where the ash door is sprung and not
seating when latched.
9. Transparent tubing from firebox to sensing
switch is off or blocked with fly ash.
10. Poor seal on the hopper lid (usually caused
by coal under hopper lid edge gasketing after
fueling).
11. Fines tray cover not closed properly, fig. 20.
12. Sensitivity of the safety switch set too high.
causing false warnings.
13. Poor or improper flue termination, other
than those shown in the owners manual.
14. Too high of negative pressure in the area
being heated. This is usually caused by the area
being too tight and using many exhausting
appliances ( range hood, clothing dryer. exhaust
fans, etc.). Often this condition can be caused
by heavy and gusting winds hitting the outside,
creating a negative pressure inside. This internal
to external pressure difference may cause the
unit to go in and out of Stage 1.
15. Faulty computer circuit or disconnected
wiring between control board and safety switch.
16. Faulty safety switch (cannot be adjusted
within proper range and function properly).
17. Draft motor failure - there is electricity to the
motor but it will not turn.
[At any time the 2 blink status can be reset by
disconnecting the power to the unit for a few
seconds.]
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