Patterson-Kelley Thermific, Installation & Owner'S Manual

Page: 27 / 46

Thermific
®
Gas-Fired Boiler Maintenance
Page 23
9. Before re-installing the burner, check the cleanli-
ness of the exchanger and the condition of the
firebox floor.
5.3 R
EMOVING THE
E
XCHANGER
1. Remove the burner as above.
2. Remove the front doors by pulling forward and
upward.
3. Remove the top panel of the inner cabinet.
4. Close the isolation valves to the system.
5. Drain the boiler.
6. Disconnect the supply and return lines.
7. Remove the pipe cross containing the temperature-
pressure indicator and relief valve along with the
tee containing the water flow switch (on the D se-
ries units disconnect at the grooved pipe coupling
[Victaulic]).
8. Remove the nuts and bolts from the flanges of the
inlet and outlet nozzles at the rear of the outer cas-
ing.
9. Remove the exchanger and clean the fins.
Note: The inner and outer cabinets are separate parts
and reassembly is easier if the inner cabinet and ex-
changer are removed together as one unit. When re-
assembling, reseal the top of inner cabinet with alumi-
num tape as needed.
WARNING!
The heat exchanger is heavy; use proper lifting
equipment and techniques.
5.4 A
FTER
A
LL
R
EPAIRS OR
M
AINTENANCE
1. Follow "Pre-Start Check List" (Section 3.10) and
all "Safety Checks" (Section 3.11).
2. Check gas pressure and adjust gas flow if neces-
sary. (See "Gas Pressure Adjustment", Section
3.12.2.)
3. Check air pressure and adjust air flow if necessary.
(See "Air Flow Adjustment", Section 3.12.3.)
4. Perform combustion check.
5.5 S
EQUENCE
O
F
O
PERATION
Status (red and green) indicators located on the front
of the control panel of this boiler are specifically de-
signed to indicate the sequence of operations and the
cause of common problems. Careful observation of
indicators should provide a guide to most operational
conditions and problems.
1. When the On/Off (main power) switch is turned
on, a green indicator marked "Power" or the amber
switch is illuminated. Power is applied through a
series of switches, including water flow, gas pres-
sure and high temperature, and through the operat-
ing temperature control to the flame-safeguard
programmer.
2. The water flow limit switch is closed when there is
water flow through the boiler.
Note: The closing of this switch does not prove
that flow is adequate. Refer to TD110 for
proper flow requirements.
3. When gas pressure is available, the low gas-
pressure limit switch is closed. Manual reset is re-
quired following conditions resulting in low gas
pressure.
4. If the temperature sensed by the high-limit tem-
perature control is below the set limit, the nor-
mally closed position of the switch sends power to
the operating temperature control. Manual reset is
required following conditions exceeding high-
temperature limit. The limit series is complete
unless an external control is placed ahead of the
water flow limit (replacing the red jumper wire).
5. When heat is required, as indicated by outlet water
temperature, power is applied to Terminal 6 of the
programmer, which initiates the burner operating
sequence, and to an indicator marked "Heat".
6. The programmer first energizes Terminal 4 which
supplies power to the contactor for the blower mo-
tor and the air flow switch, which initially shows
low air flow with the "Low Air" indicator. This
indicator will remain on until sufficient air flow is
sensed (approximately 5-8 seconds).