Aerovent IM-500 - Manual (Page 14)

14 Aerovent IM-500
11. Turn unit off IMMEDIATELY and check the blower
for proper rotation of wheel. Correct if required by
reversing two of the three leads supplying power from
the starter. If soft start or VFD is installed consult the
instruction manual that was included with the unit to
change rotation.
12. Turn unit back on and check to make sure that the
damper opens fully without binding, also check the
motor and blower speed with the strobe for rpm.
13. With the voltmeter check motor voltage on all three phas-
es of the systems to make sure all legs are in balance.
14. With the amp meter check motor amp draw to make
sure it does not exceed the motor nameplate rating. On
three phase systems, check all legs to insure system is
balanced.
NOTE: The first main gas hand cock will have to be
opened at this time and the high and low gas pressure
switches must be reset. However, the second main hand
valve, (located before the modulating gas valve) should be
kept in the closed position.
15. Recheck gas supply pressure. Gage should show pres-
sure as marked at the gage.
16. Check pilot and pilot ignition. Open pilot gas hand
cock only.
17. Check to make sure that all manual reset safety devices
have been reset to their normal operating position.
18. Move the Summer/Off/Winter switch to “Winter”.
Move temperature controls to call for heat.
NOTE: The mild temperature control set point needs to
be set above the ambient outside temperature to allow the
pilot and igniter to function. (Do not forget to reset to 65 o F
after final system checks are completed.)
19. Check to see that the pilot lights properly. The spark
igniter should begin to spark in approximately 10 sec-
onds and pilot flame should be established within 10
seconds.
20. The unit is supplied with an ultra violet flame detec-
tor (UV) scanner. With the UV detector (scanner), the
output of the detector should be stable and should be
between 1.25 and 5V DC at the flame relay terminals.
Adjust pilot regulator if the readings are outside of the
specified ranges by removing cap screw and adjusting
pilot flame with pilot needle valve. Best results are
obtained with smallest possible flame 1 /
2
- 1 1 /
2
turns
clockwise from fully closed position.
21. Check to make sure the flame sensor and flame safe-
guard relay is operating correctly. To check, shut off
the pilot gas hand valve while the pilot is still on. The
pilot igniter should try for ignition within 2 to 4 sec-
onds. If pilot cannot be reestablished, the flame safe-
guard control should go into lockout. (If the flame
safeguard does not go into lockout, contact
factory.)
22. Turn the pilot gas hand cock to the on position and
reset the flame safeguard relay using the manual reset
button on the relay. Allow the unit to establish pilot.
23. Check the airflow sensing device switch by blocking
off 30% of the inlet to the unit. The system should
shut down. With the pilot established, increase the
pressure setting of the airflow proving switch by turn-
ing the adjustment screw on the switch clockwise.
Increase the setting until the pilot drops out. Back off
of this setting two turns enough to allow the pilot to
reignite. (If pilot does not drop out during this
check, inspect the switch for damage and
replace if required.)
24. Check continuity of limit control contacts and wiring.
(Unit will not try for ignition if limit control
is faulty.) The high limit control is factory set and
does not require field adjustment.
NOTE: THE MAXIMUM GAS PRESSURE GAS
MANIFOLD CAN SAFELY HANDLE WITHOUT
DAMAGING THE CONTROLS IS 5 PSI.
25. Open main gas cock and check gauge gas pressure
reading. The pressure reading on the gauge should be
at factory noted hash mark. (See unit rating or
system spec for high fire burner pressure
setting. Also see manifold component dia-
grams.)
26. Observe low fire flame to make sure it LIGHTS
ACROSS THE ENTIRE LENGTH of the burn-
er is stable and burning with a clean blue flame.
27. Move the Maxitrol temperature setting control to its
highest setting and observe the high fire flame. Make
sure that it is stable and burning clean. A slightly
orange tip may be evident and is acceptable.
28. High Fire Adjustment: Disconnect lead #4 on series
14 or leads #2 and #4 on series 44 from the amplifier
which will cause the burner to go to a high fire condi-
tion. The flame length should be 10 in. and burn with
a slight orange tip. Adjust the pressure regulator in the
Maxitrol valve accordingly by removing the seal cap
adj. pressure reg. screw (should give manifold pressure
of 7 in.) Return wires to terminals when adjustments
are complete.
29. Low Fire Adjustment: Disconnect wire from term #8
in the amplifier. Remove cap and obtain a flame that is
a “ribbon” across the entire burner being sure flame is
stable. Tighten the setscrew, replace the cap and recon-
nect wire to term #8.
30. Check the burner gas pressure at high fire to make sure
the unit is not over or under fired.
If the burner is not firing at the pressure marked
on the unit’s gas pressure gauge, adjust the main
supply pressure regulator accordingly.
31. After the high fire pressure has been checked and reset
if necessary, turn the temperature controls down to
their lowest setting and recheck the low fire burner
flame. It should still be stable and burning clean.