CTHN-S
ERIES
I
NSTALLATION
, O
PERATION
AND
S
ERVICE
M
ANUAL
72 of 91
SECTION 17: OPERATION AND MAINTENANCE
The CTHN-Series heater is eq
u
ipped
w
ith a direct
spark ignition system.
17.1 Checking the Gas Line
1. Open main valve and verify that no gas is
flo
w
ing thro
u
gh the gas meter.
2. P
u
rge the line if this
w
as not done follo
w
ing
press
u
re testing
w
ith air.
3. Verify that the gas press
u
re is not above 14"
w
c
(1/2 PSIG)
4. Close main gas valve.
17.2 Unitary Heater Se
q
uence of Operation
1. T
u
rn the thermostat
u
p. When the thermostat
calls for heat, the blo
w
er motor
w
ill energize.
2. When the fan motor achieves normal r
u
nning
RPM, the press
u
re s
w
itch
w
ithin the b
u
rner
closes and energizes the ignition mod
u
le.
3. After a 45 second pre-p
u
rge, the ignition mod
u
le
then opens the gas valve and energizes the
electrode. When the flame is established, the
sparking seq
u
ence ceases.
4. If the flame is not established d
u
ring the ignition
seq
u
ence, the ignition mod
u
le closes the gas
valve and p
u
rge begins. The ignition mod
u
le
w
ill
try 2 additional times for ignition (
w
ith p
u
rge
bet
w
een). If ignition is not established, the
mod
u
le
w
ill lock-o
u
t.
NOTE: After 1 ho
u
r, the mod
u
le
w
ill reset
a
u
tomatically and ret
u
rn to steps 3 and 4.
5. If a flame is detected, the gas valve remains
open. When the call for heat is satisfied, the
thermostat t
u
rns off the b
u
rner and fan po
w
er
s
u
pply.
6. If the flame exting
u
ishes d
u
ring operation, the
ignition mod
u
le
w
ill attempt to re-establish the
flame as described in the preceding step. If
ignition is not re-established, the mod
u
le
w
ill
lock-o
u
t.
7. After lock-o
u
t, the control m
u
st be reset by
t
u
rning do
w
n the thermostat for five seconds,
then raising it again to the desired temperat
u
re,
or by disconnecting and re-connecting po
w
er to
the control.
17.2.1 To Shut Off Heater - Unitary
Set thermostat to lo
w
est setting.
T
u
rn OFF electric po
w
er to heater.
T
u
rn OFF man
u
al gas valve in the heater s
u
pply line.
Cut/Pinch Hazard
Wear protective
g
ear
durin
g
installation,
operation and service.
Ed
g
es are sharp.
WARNING
Failure to follow these instructions can result in death, electric shock, injury or property dama
g
e.
Burn Hazard
Allow heater to cool
before service.
Tubin
g
may still be hot
after operation.
Explosion Hazard
Turn off
g
as supply to
heater before service.
DANGER
Electrical Shock Hazard
Disconnect electric
before service.
More than one
disconnect switch may
be required to
disconnect electric from
heater.
Heater must be
connected to a properly
g
rounded electrical
source.
