Thermostat Closed, Fan Operates, No Glo-Bar Energization
(cont.)
(This step is applicable for all models)
2.3
The
Exhaust
Pressure Switch
is located on the valve side of the heater
(pg. 6, pic. 4)
.
*
Bypass this switch
(pg. 21, #6)
. If the heater works with the exhaust pressure switch bypassed, the problem is with this switch or what
it is sensing and you should continue with step 2.3.1. If bypassing this switch does not cause the heater to work,
continue with step 2.4.
2.3a
Be sure the lid is on correctly and tightly, and the gasket is in intact.
2.3b
Check to make sure the clear vinyl or aluminum tube that bleeds pressure to the outside of the heater is
clean and clear of obstructions.
2.3c
Clean any obstructions from the emitter tube, exhaust tube and vent cap.
2.3d
Check to make sure the heater’s baffle is located properly. It should be found at the exhaust end of the
emitter tube.
NOTE: Excessive winds may cause properly operating safety pressure switches to shut down the heater. Heaters ducted
through (on either the intake or exhaust sides) the roof may be deprived of the air necessary to pressurize the burner box. This
“chimney effect” will typically not allow the burner pressure switch to close. Heaters vented through a sidewall may see too
much back-pressure, thus opening the exhaust pressure switch. In either case, the caps need to be shielded to lessen the effects
of high winds.
2.3e
Check to make sure the sensing tube pointed in the outlet of the fan is at the bottom of the opening
(pg 5,
pic. 4)
2.3f
If steps 2.3a - 2.3e were performed and the heater still won’t properly function, the exhaust pressure switch
is faulty.
2.4(-2)
(This step is applicable for non-DTHS-2 & DTHS-2 model heaters 40-100 MBTU/H).
Check the normally closed radiant sensor to see if it is stuck in the open position. See how to
(pg. 22, #8)
. If stuck
open, the radiant sensor can be bypassed. See “How To”
(pg. 22, #7)
to confirm that there are no other failures.
2.4(-3)
(This step is applicable for DTHS-3 models only)
Check the
Circuit Board (pg. 6, pic. 3)
. Use a volt meter to ensure that power is actually entering the circuit
board. Turn off the gas to the heater and
*
bypass both pressure switches
(pg. 21, #6)
, as a heater with no cover will
not allow pressure switches to function properly. 120 volts exiting the circuit board indicates that the glo-bar is
faulty. If no voltage exits the circuit board, it is faulty.
13
Refer to warnings on cover prior to servicing the unit. Bypass safety pressure switches for supervised troubleshooting purposes only.
*Do not leave switches bypassed while the heater is unattended or for normal operations.
Consult Detroit Radiant Products for further technical information.
Solution 2