Check Safety Controls - HEIL F8MVL Installation Instructions Manual

Table 14 − Orifice Size and Manifold Pressure (In. W.C.) for Gas Input Rate (Con't.)
(Tabulated Data Based on 22,000 Btuh High−Heat/14,500 Btuh for Low−Heat per Burner, Derated 4 Percent for Each 1000
AVG. GAS
ALTITUDE
HEAT VALUE
RANGE
AT ALTITUDE
FT. (M)
(BTUH/CU FT.)
675
700
6001 to 725
7000 750
USA
(1829 to 775
2134)
800
825
850
AVG. GAS
ALTITUDE
HEAT VALUE
RANGE
AT ALTITUDE
FT. (M)
(BTUH/CU FT.)
650
675
7001 to 700
8000 725
USA
(2134 to
750
2438)
775
800
825
AVG. GAS
HEAT VALUE
ALTITUDE
RANGE AT ALTITUDE
(BTUH/CU FT.)
625
650
8001 to
675
9000
700
USA
(2438 to
725
2743)
750
775
AVG. GAS
HEAT VALUE
ALTITUDE
AT ALTITUDE
RANGE
(BTUH/CU FT.)
600
9001 to
625
10,000 650
USA
2743 to 675
700
3048)
725
* Orifice numbers 43 are factory installed

Check Safety Controls

The flame sensor, gas valve, and pressure switch were all
checked in the Start−up procedure section as part of normal
operation.
1. Check Main Limit Switch
This control shuts off combustion system and ener-
gizes air−circulating blower motor, if furnace overheats.
By using this method to check limit control, it can be
established that limit is functioning properly and will op-
erate if there is a restricted return−air supply or motor
failure. If limit control does not function during this test,
cause must be determined and corrected.
a. Run furnace for at least 5 minutes.
b. Gradually block off return air with a piece of card-
board or sheet metal until the limit trips.
c. Unblock return air to permit normal circulation.
d. Burners will re−light when furnace cools down.
441 01 2121 01
Ft. Above Sea Level)
0.58
Manifold
Orifice Orifice
Pressure
No. No.
High/Low
43 3.4/1.5 43
44 3.6/1.6 43
44 3.4/1.5 44
45 3.8/1.7 44
46 3.7/1.6 45
46 3.5/1.5 46
47 3.7/1.6 46
47 3.5/1.5 47
0.58
Manifold
Orifice Orifice
Pressure
No. No.
High/Low
44 3.6/1.6 43
44 3.3/1.5 44
45 3.8/1.6 44
46 3.7/1.6 46
46 3.4/1.5 46
47 3.6/1.6 47
47 3.4/1.5 47
48 3.7/1.6 48
0.58
Manifold
Orifice Orifice
Pressure
No. No.
High/Low
44 3.3/1.5 44
45 3.7/1.6 44
46 3.6/1.6 46
47 3.8/1.7 46
47 3.6/1.6 47
48 3.8/1.7 47
48 3.6/1.5 48
0.58
Manifold
Orifice Orifice
Pressure
No. No.
High/Low
45 3.7/1.6 45
46 3.6/1.6 46
47 3.8/1.6 46
47 3.5/1.5 47
48 3.7/1.6 48
48 3.5/1.5 48
SPECIFIC GRAVITY OF NATURAL GAS
0.60
Manifold
Orifice
Pressure
No.
High/Low
3.5/1.5 43
3.3/1.4 43
3.5/1.5 44
3.3/1.4 44
3.7/1.6 45
3.6/1.6 46
3.4/1.5 46
3.6/1.6 47
SPECIFIC GRAVITY OF NATURAL GAS
0.60
Manifold
Orifice
Pressure
No.
High/Low
3.2/1.4 43
3.5/1.5 44
3.2/1.4 44
3.8/1.7 45
3.6/1.5 46
3.8/1.6 46
3.5/1.5 47
3.8/1.6 47
SPECIFIC GRAVITY OF NATURAL GAS
0.60
Manifold
Orifice
Pressure
No.
High/Low
3.5/1.5 44
3.2/1.4 44
3.8/1.6 45
3.5/1.5 46
3.7/1.6 47
3.5/1.5 47
3.7/1.6 48
SPECIFIC GRAVITY OF NATURAL GAS
0.60
Manifold
Orifice
Pressure
No.
High/Low
3.8/1.7 44
3.7/1.6 46
3.4/1.5 46
3.6/1.6 47
3.8/1.7 47
3.6/1.6 48
2. Check draft safeguard switch. The purpose of this con-
trol is to cause the safe shutdown of the furnace during
certain blocked vent conditions.
a. Verify vent pipe is cool to the touch.
b. Disconnect power to furnace and remove vent con-
nector from furnace vent elbow.
c. Restore power to furnace and set room thermostat
above room temperature.
d. After normal start−up, allow furnace to operate for 2
minutes, then block vent elbow in furnace 80 per-
cent of vent area with a piece of flat sheet metal.
e. Furnace should cycle off within 2 minutes. If gas
does not shut off within 2 minutes, determine reas-
on draft safeguard switch did not function properly
and correct condition.
f. Remove blockage from furnace vent elbow.
g. Switch will auto−reset when it cools.
0.62 0.64
Manifold
Orifice
Pressure
No.
High/Low
3.6/1.6 43
3.4/1.5 43
3.6/1.6 43
3.4/1.5 44
3.8/1.7 44
3.8/1.6 45
3.5/1.5 46
3.8/1.6 46
0.62 0.64
Manifold
Orifice
Pressure
No.
High/Low
3.4/1.5 43
3.6/1.6 43
3.3/1.4 44
3.7/1.6 44
3.7/1.6 46
3.4/1.5 46
3.7/1.6 47
3.4/1.5 47
0.62 0.64
Manifold
Orifice
Pressure
No.
High/Low
3.6/1.6 43
3.3/1.4 44
3.7/1.6 45
3.6/1.6 46
3.8/1.7 46
3.6/1.6 47
3.8/1.7 47
0.62 0.64
Manifold
Orifice
Pressure
No.
High/Low
3.3/1.4 44
3.8/1.7 45
3.6/1.5 46
3.7/1.6 46
3.5/1.5 47
3.7/1.6 48
Manifold
Pressure
High/Low
3.7/1.6
3.5/1.5
3.2/1.4
3.5/1.5
3.2/1.4
3.7/1.6
3.6/1.6
3.4/1.5
Manifold
Pressure
High/Low
3.5/1.5
3.2/1.4
3.4/1.5
3.2/1.4
3.8/1.6
3.6/1.5
3.8/1.6
3.6/1.5
Manifold
Pressure
High/Low
3.2/1.4
3.4/1.5
3.8/1.7
3.7/1.6
3.5/1.5
3.7/1.6
3.5/1.5
Manifold
Pressure
High/Low
3.4/1.5
3.8/1.6
3.7/1.6
3.4/1.5
3.6/1.6
3.8/1.7
39