Valve Proving System - Honeywell 7800 Series Installation Instructions Manual

Keyboard Display Module
The KDM (see Fig. 5) is provided with the RM7838B,C
Relay Module. The first line of the Vacuum Fluorescent
Display (VFD) provides:
a. Current status of the burner sequence
(STANDBY, PURGE, PILOT IGN, MAIN IGN and
RUN).
b. Timing information (PURGE, PILOT IGN and
MAIN IGN) in minutes and seconds.
c. Hold information (PURGE HOLD: T19).
d. Lockout information (Lockout, Fault Code, Mes-
sage and Sequence).
The extreme right side of the first line is either blank or
shows a small arrow pointing to the second line followed
by a two-letter code (DI—Diagnostic Information, H1—
Fault History Information, and EA—Expanded
Annunciator). When the arrow and two-letter code are
displayed, it indicates the second line is showing a
selectable message submenu. The second line displays
selectable or preemptive messages.
A selectable message supplies information such as flame
strength, system status indication, system or self-
diagnostics and troubleshooting. Refer to checkout and
troubleshooting instructions; see applicable publications
listed on page 1.
A preemptive message has parentheses around the
message and supplies a detailed message to support the
sequence status information. A preemptive message can
also be a lockout message. It also replaces a selectable
message after 60 seconds if it or a lockout message is
available.
NOTE: RM7838B,C LED provide positive visual
indication of the program sequence: POWER,
PILOT, FLAME, MAIN and ALARM. See Fig. 5.
203541 FIVE-WIRE CONNECTOR FOR
COMMUNICATIONS, REMOTE
KEYBOARD DISPLAY AND REMOTE RESET
RUN/TEST SWITCH
SEQUENCE
STATUS
SELECTABLE
MESSAGE OR
PRE-EMPTIVE
MESSAGE
SEQUENCE
STATUS
LEDs
RESET
PUSHBUTTON
FLAME
SIMULATOR INPUT
Fig. 5. Relay Module and associated system
components.

VALVE PROVING SYSTEM

The Valve Proving System feature provides a systematic
way of testing the valve seat integrity to assure the valves
are in the closed state whenever the sequence of
operation requires them to be closed. It is designed to
detect a leak greater than 0.1% of the burner input
capacity. For example, a 10 million Btu/hr natural gas-
fueled burner would have a fuel input capacity of
approximately 1,000 ft
of 1,000 ft
with the Valve Proving System. Smaller leaks will not be
detected.
At commissioning time, the Valve Proving System may be
scheduled to occur at one of five different times: Never,
Before, After, Both, and Split.
The Valve Proving items programmed are:
DI = DIAGNOSTICS
Typical Valve Proving System
H1 = HISTORY
EA = EXPANDED
Function
ANNUNCIATOR
CAPTIVE Valve proving consists of monitoring the pressure in the
MOUNTING
space between two shutoff valves, MV1 (upstream) and
SCREW
MV2 (downstream). The valve proving function, identified
PLUG-IN
by letters A through G, operates as follows:
PURGE
CARD
The tolerance on all valve proving timing values is ±10%.
KEYBOARD
DISPLAY
The following are steps performed during valve proving
MODULE
tests. This section is for background information and does
RELAY
not define the exact behavioral requirements.
MODULE
FLAME
AMPLIFIER
FLAME CURRENT
TEST JACKS M7359B
11
RM7838B, RM7838C 7800 SERIES RELAY MODULES
3
/hr. A leak rate greater than 0.1%
3 3
/hr or 1 ft /hr in either valve will be detected
Never—Device default as received: in this case Valve
Proving does not occur.
Before—Valve Proving occurs concurrent with Prepurge
and before the Start Switch (T21).
After—Valve Proving occurs after the Run state (Stop
Switch) before the internal Safety Relay dropout state
and concurrent with Postpurge (if configured).
Both—Valve proving occurs at both times Before and
After noted above.
Split—The downstream seat (high pressure) test is per-
formed at the Before time and the upstream seat (low
pressure) test is performed during the After time.
1. Enable Valve proving and, if so, when to perform it.
2. The time duration of the test is calculated from
Appendix A.
A. MV2 is commanded to be open while MV1 remains
closed, to depressurize the space. After 4 seconds, MV2
is commanded closed again.
B. This is followed by a three second delay during which
the valve proving pressure switch (VPS) is ignored.
C. Thereafter, the VPS is monitored for the duration of
the valve proving test time and, if it turns on, then a
lockout occurs. (Because the gas pressure has
increased due to a leaky upstream valve.) (Low pressure
test.)
32-00211—01