Part 6; Start Up Procedures; Sequence Of Operation - Heat Transfer Munchkin VWH User Manual

PART 6. START-UP PROCEDURES
A. SEQUENCE OF OPERATION
The VWH boilers are shipped with light blue wires connected using a wire nut, which controls stor-
age tank temperature through the supply manifold sensor located on the heater. The light blue wires
can also be connected to allow the user to control the storage tank temperature directly using a
Mechanical Aquastat Control (Not included in package) or Tank Sensor which would be mounted
directly on the storage tank. All VWH boilers should be set up to run the pump continuously to
assure long service life and accurate temperature measurement.
1. When power is first applied to the control, the control display will read the outlet tempera-
ture. The control will initially run through a self-diagnostic routine and then go into its oper-
ating mode. If there is no call for heat, the System will go into an idle state. The circulator
must be wired to incoming power to operate continuously. If there is a code | F L| in the display
window, then either the circulator is not operating or there is a restriction in the piping sys-
tem, rendering an inadequate flow.
2. The control then performs selected system diagnostic checks. If all checks are successfully
passed, a pre-purge cycle is initiated (the blower will be on maximum speed).
3. When the actual temperature is below a set-point, minus the switching differential, the burn-
er will operate and modulate to heat the system. If using a mechanical control on the storage
tank, the burner will not activate until the control calls for heat. This will activate the burner
and modulate the heater off the programmed set-point value on your Munchkin VWH unit. It
is recommended that the VWH control set-point is 5° higher than the set-point on the
mechanical control.
4. When the pre-purge period is complete, power is applied to the spark ignitor for approxi-
mately 6 seconds. Approximately 2 seconds later, we verify flame. If a flame is not verified
during the trial-for-ignition, the gas valve is immediately closed and the control will return to
step 2. After three trials, if a flame is not verified, the control will go into a lockout mode. If a
flame is confirmed, the control enters the heating mode. The fire rate will be based on the
proprietary algorithm.
5. When water temperature reaches the temperature set point, the gas valve is closed and the
control enters a post-purge state (the blower will be on maximum speed).
6. When the post-purge is complete, the control enters an idle state while continuing to moni-
tor temperature and the state of other system devices. If a call-for-heat is received, the con-
trol will automatically return to step 2 in sequence and repeat the entire operating cycle.
CHECK/CONTROL WATER CHEMISTRY
Water pH between 6.0 and 8.0
1. Maintain boiler water pH between 6.0 and 8.0. Check with litmus paper or have chemically
analyzed by water treatment company.
2. If pH differs from above, consult local water treatment company for treatment needed.
Hardness less than 7 grains.
1. Consult local water treatment companies for unusually hard water areas (above 7 grains hardness).
Chlorine concentration less than 200 ppm
1. Filling with chlorinated fresh water should be acceptable since drinking water chlorine levels are
typically less than 5 ppm.
2. Do not use the boiler to directly heat swimming pool or spa water.
3. Do not fill boiler or operate with water containing chlorine in excess of 200 ppm.
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START-UP PROCEDURES