86
Direct-Fired Make-up Air •
MUA-SVX01A-EN
Trouble Shooting
11. Discharge air
temperature too low
when room override
thermostat is operative.
Override temperature
setting is too low.
Check override
temperature selector of
remote temperature
selector.
a. Reset to
correct
temperature.
Burner capacity may be
insufficient.
Check for high fire
(Maxitrol manifold
pressure specified for
heater).
a. If on high
fire, control
can do no
more. Heater
unable to
furnish
additional heat
to raise
temperature.
12. Discharge
temperature to the
same as setpoint.
Duct losses.
Room temperature control
solutions should maintain
an accuracy of ±3°F. If
not, the controller may be
calibrated in two ways.
a. The
potentiometer
on the face of
the direct fired
control labeled
ADJUST will
adjust the
discharge
temperature
by ±10°F
when rotated.
Rotating it
clockwise will
increase the
temperature
and counter
clockwise will
decrease the
temperature.
b. The system
may also be
adjusted from
the remote
temperature
selector by
adjusting the
potentiometer
R3 on the back
in the same
procedure as
shown above.
Table 18.
Trouble shooting guide for Modulationg Room Temperature (MRT)
controls
Symptom
Probable Cause
Field Test
Solution
1. No gas flow.
Modulating valve
improperly installed.
Arrow on side of valve
should point in direction
of gas flow.
a. Install
properly.
*
Control circuits external to MRT controls can cause burner malfunction. Always check manual valve
to be certain gas is on, and check limit controls for normal operation.
Table 17.
Trouble shooting guide for Modulating Discharge Temperature (MDT)
Controls (continued)
Symptom
Probable Cause
Field Test
Solution
