MORTEX
PRODUCTS
INC
501
TERMINAL
RD
FORT
WORTH,
TX
76106
Page
27
SECTION VII FURNACE STARTUP,
DIAGNOSTICS AND SEQUENCE OF
OPERATION
CHECKING THE INPUT RATE
TOOLS REQUIRED TO PERFORM FURNACE
STARTUP PROCEDURE
1.
A thermometer or portable digital thermometer to measure
the supply and return temperatures.
2.
A “U” tube monometer or portable pressure gauge that
measures 0-15 in-wc. (0-3.735 kPa) to measure the line
pressure and the manifold pressure.
3.
A 3/32” (2.4 mm) alien wrench to open and close the gas
valve pressure port plugs.
4.
Two (2) pieces of 1/8” (3.175 mm) ID flexible tubing, 12”
(304.8 mm) long.
Startup Sequence
1.
Turn the gas supply line valve to the “ON” position.
2.
Set the thermostat above the room temperature to obtain a
call for heat.
3.
System startup will occur as follows:
a.
The induced draft blower motor will start and come up
to speed.
b.
This will cause the air pressure in the induced draft
housing to increase closing the pressure switch contacts
once 0.55” w.c (0.137 kPa) +/- .05” w.c (0.01245 kPa)
has been reached.
c.
Once the pressure switch is closed the ignitor is
energized. There is a 17 second warm up to give the
ignitor time to reach its operating temperature.
d.
After the 17 second ignitor warm up the gas valve is
energized. Gas starts to flow, ignition occurs and flame
sensor begins sensing the flame.
e.
65 seconds after flame sense begins the blower motor
will start on the control board speed tap terminal
labeled “HEAT”. The 115 VAC will energize the
blower relay coil closing the normally open contacts #2
and #4 sending 24 VAC to the selected blower motor
speed tap that is connected to terminal #4 on the
blower relay. Factory default is the Medium speed tap
wire is placed on terminal #4 on the blower relay
If the sensor does not sense a flame the blower will not
start.
CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below for each appliance connected to the venting system being placed into operation could
result in carbon monoxide poisoning or death.
The following steps shall be followed for each appliance connected to the venting system being placed into operation, while all other
appliances connected to the venting system are not in operation:
1.
Seal any unused openings in the venting system.
2.
Inspect the venting system for proper size and horizontal pitch, as required in the
National Fuel Gas Code
, ANSI
Z223.1/NFPA 54 or the
Natural Gas and Propane Installation Code,
CSA B149.1 and these instructions. Determine that
there is not blockage or restriction, leakage, corrosion and other deficiencies which could cause an unsafe condition.
3.
As far as practical, close all building doors and windows and all doors between the space in which the appliance(s)
connected to the venting system are located and other spaces of the building.
4.
Close fireplace dampers.
5.
Turn on clothes dryers and any appliance not connected to the venting system. Turn on any exhaust fans, such as range
hoods and bathroom exhausts, so they are operating at maximum speed. Do not operate a summer exhaust fan.
6.
Follow the lighting instructions. Place the appliance being inspected into operation. Adjust the thermostat so appliance is
operating continuously.
7.
Test for spillage from draft hood equipped appliances at the draft hood relief opening after 5 minutes of main burner
operation. Use the flame of a match or candle.
8.
If improper venting is observed during any of the above tests, the venting system must be corrected in accordance with
the
National Fuel Gas Code
, ANSI Z223.1/NFPA 54 and/or
Natural Gas and Propane Installation Code.
CSA B149.1
9.
After it has been determined that each appliance connected to the venting system properly vents when tested as outlined
above, return doors, windows, exhaust fans, fireplace dampers and any other gas-fired burning appliance to their previous
conditions of use.
To avoid personal injury or property damage, make certain
that the motor leads cannot come into contact with non-
insulated metal components of the unit.
Check the gas inlet pressure at the unit upstream of the
combination gas control. The inlet pressure should be 6-
7" W.C. (1.494-1.743 kPa) on natural gas or 10-12" W.C.
(2.49-2.988 kPa) on propane. If inlet pressure is too high,
install an additional pressure regulator upstream of the
combination gas control.
