Harman DVC-500, Installation & Operating Manual

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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 warnings
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 condi-
tion 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 condition 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 align-
ment, 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 blink status can be reset by
disconnecting the power to the unit for a few
seconds.]
DVC-00 Firebox Static Pressure Safety Protocol