Service manual

40
Locate screw (2) labeled as and make
adjustments as necessary to satisfy the
combustion values in Table 16. The markings on
the setting screws are labeled as “+” and “-“, for
more and less gas, respectively. Turn the screw
1/4 turn in either way for each adjustment to
keep track of the adjustments. After adjusting
the screw wait a moment for the combustion
levels to stabilize before attempting to make any
further adjustments. Continue this procedure
until combustion levels are satisfied.
Reset the Target Temperature to normal
operating conditions on the BTC 1 Controller.
Table 16 – Combustion Values
Natural Gas
Propane
CO
2
CO CO
2
CO
Non-
Condensing
Max.
Fire
7.5% -
8.5%
< 50
PPM
9.0% -
10.0%
< 50
PPM
Min.
Fire
7.0% -
7.5%
< 50
PPM
8.5% -
9.0%
< 50
PPM
Condensing
Max.
Fire
8.5% -
9.0%
< 50
PPM
10.0% -
10.5%
< 50
PPM
Min.
Fire
7.5% -
8.0%
< 50
PPM
9.0% -
9.5%
< 50
PPM
Pilot Flame Rectification Setting
The pilot flame rectification was preset at the
factory. The following description is for the
benefit of the start-up technician should minor
adjustment be required. Set pilot to obtain best
µA reading from flame rectification. Minimum
average signal of 1.5 µA is required. If required,
test the signal using a DC µA meter following
this procedure for Honeywell S8600 ignition
module: Disconnect ground wire at appliance
transformer; Disconnect the 24V power and
ground wires from all S8600 ignition modules
not being tested; Set meter to µA DC: Connect
one of the meter’s terminals to the burner
ground terminal on the S8600 and the other
terminal to the burner ground wire; Pilot running
without main burner will generate 1.5 µA
average for best operation. With main burner
running, the signal will be in a range of 4.0 to 7.0
µA.
The normally-closed blocked flue switch has
been preset at the factory. In cases where the
heater loses the flame signal as it approaches
high fire adjustment to the blocked flue switch
may be necessary.
The following description is for the benefit of the
start-up technician should minor adjustment be
required.
a. Remove the lower front jacket panel
b. Reduce sensitivity of blocked flue switch
by turning the flat screw ¼ turn
clockwise
c. Observe the operation of the burner as it
approaches high fire, if the heater
continues to operate at high fire the
switch has been correctly set. If not,
repeat steps 2 and 3.
d. Re-install lower front jacket panel
Differential Air Proving Switch
A differential low fire air proving switch is
provided on every burner to prevent burner light
off under block flue or blocked inlet condition.
The normally-open differential air switches have
been preset at the factory. The following
description is for the benefit of the start-up
technician should minor adjustment be required.
1) Remove the lower front jacket panel
2) Insert allen key into the switch located
on the combustion chamber door
3) Reduce sensitivity of differential air
switch by turning the hex screw ¼ turn
counter-clockwise.
4) Re-install lower front jacket panel
Ignition System Safety Shut-Off Device
After initial fill while the main burner is firing,
shut off gas to the pilot and clock the time taken
for the main gas valve to shut down. If the safety
control is functioning properly, power to the gas
valve will be shut off within 4 seconds of the pilot
gas being shut off. If shut down takes longer,
ignition control or gas valve may be defective. If
shutdown does not occur it is possible that the
main gas flow is generating a signal at the pilot
in which case the pilot shall not recycle with the
pilot gas off.
Appliances Start Up
With the appliance off, open makeup water valve
and allow system to fill slowly. With all air vents
open, run system circulating pump for a
minimum of 30 minutes with the appliance off.
Open all strainers in the circulating system and
check for debris. Check liquid level in expansion
tank. With system full of water at 15 PSIG cold,