Engineering Specs

3
F. Controls and Safeties:
1. General:
a. Electrical Rating: The burner will operate on a 115Vac, 60Hz electrical supply with a
current rating of no less than 1.5A at 115Vac
b. Heater gas and ignition controls will be readily accessible for servicing.
c. The burner will have solid state direct spark ignition and flame sensor control that is
dedicated to secure the operation of the burner
2. Ignition and Flame Control:
a. To complete the direct spark ignition system the burner will incorporate a gas control and
24Vac transformer
b. Burner will be complete with a low voltage (24Vac), solid state direct spark ignition and
ionization flame sensing control module that will provide a 45 second pre-ignition purge of
the system by the blower. Electrical Rating: 24Vac, 60Hz with current rating of 0.2A at
24Vac
c. Burner will be complete with an igniter/sensor to provide spark ignition and flame
sensing.
d. The ionization module will sense the presence of main burner flame and discontinue
spark ignition. If the burner fails to ignite within the trial-for-ignition period, the ignition
module will try 3 times with 30 seconds inter-purge. After that flame control will go into
safety lockout. It will begin the sequence again in 60 minutes. Reset of the control is
manually done from the thermostat too.
e. The ionization module will check for a false flame condition (short to ground) and lock out
if a false flame condition is present.
f. The ignition module will have a 15 second trial-for-ignition period
g. The ignition module will open the main gas valve and generate 25,000 volts at the spark
igniter for direct ignition of the burner.
h. On a loss of burner flame the ignition sequence goes in to recycle mode. Safety lockout
occurs if flame is not reestablished within the three trial-for-ignition. Reset of the control is
manually done from the thermostat or electrical supply.
3. Gas Control:
a. Heater will be complete with a direct ignition gas control with a manual valve, two
automatic operators, and a pressure regulator
Electrical Rating: 24Vac, 60Hz; draw 0.5A with both operators energized
b. The gas control will have an inlet pressure tap and an outlet pressure tap to facilitate
measurement of gas supply and manifold pressures during servicing.
c. Heater will be complete with a ½” pipe nipple for connection to the gas supply.
4. Heater Temperature Control:
a. Burner will be complete with an inducer blower relay built in the ignition module. An
optional thermostat of 120VAC can be connected to the main 120VAC power line or a
24Vac thermostat to TR & TW of the terminal block of the burner
b. If multiple heaters are to be controlled in a zone by a single 24Vac thermostat, 24VAC
relays will be installed from 2
nd
burner onwards, detailed as per the wiring diagram in the
manual
c. Space Heating: Each heater zone will be controlled by a 24 Vac infrared set-back
thermostat, or other 24 Vac or 120Vac thermostat as supplied by the manufacturer
5. Safety Controls:
a. Burner will be complete with a differential pressure switch in the ignition system electrical
circuit that will close upon proving a sufficient supply of combustion air from the blower
and will open upon pressure resulting from a blocked flue condition in the tube system or
insufficient blower pressure