A
HE, DE & RE MANUAL
IOM-26
15 of 33
Oct 12 R4
DE PROCESS HEATER INSTALLATION REQUIREMENTS
1. DE Series process air heaters require the installation of a manual emergency gas shutoff valve in an
appropriate location that allows access to this valve to shut off the fuel to this heater in case of a fire or
explosion at the heater or the space served by the heater.
2. If the space served by this DE Series process air heater can be entered by personnel:
a. The access opening(s) to the space shall be equipped with door interlock switch(es) to prevent the
operation of the heater during a bake cycle when an access door is opened.
b. It is recommended that warning signage be posted each access opening with wording equivalent
to:
Do not enter this space until the ventilation/cool down cycle is complete.
3. If the space served by this DE Series process air heater is intended to be entered by personnel
following a bake cycle, the space should be ventilated to purge contaminants from the space and cool
the products to avoid a burn hazard. The cool down cycle control is normally provided as part of the
remote panel. See the unit function and wiring diagrams.
4. If this DE Series process air heater has a re-circulating mode that draws air from the space being
served, filters shall be provided in the return air duct system that are approved by the authority having
jurisdiction if there is airborne particulate matter that could be detrimental to the operation of the heater.
If airborne particulate matter could accumulate in the duct system in the re-circulating mode, the return
air duct system shall be installed with doors, panels, or other means to facilitate inspection,
maintenance, cleaning, and access to fire protection devices. Periodic inspection and cleaning of the
re-circulating air duct system is required
The duct systems shall be designed to prevent recirculation of insufficiently diluted products of
combustion.
5. The minimum amount of ventilation air supplied to the space in re-circulation mode must exceed 200
cfm per 1000 cfh of natural gas based on the maximum capacity of the heater plus an allowance to
sufficiently dilute the VOC’s created by the process to maintain the lower explosive level (LEL) below a
25 percent threshold value. Refer to the unit rating plate for this information.
6. If this DE Series process air heater serves a paint booth refer to the unit function and wiring diagram
provided for the following:
a. Wiring the paint spraying equipment interlock. This prevents operation of the paint spraying
equipment unless the process heater is operated in the ventilation air mode.
b. An automatic purge (ventilation) air mode is provided for an minimum of three (3) minutes or a
minimum of four (4) air changes of the paint booth volume, whichever is greater at the start of the
bake or drying cycle with the paint spraying equipment locked out.
c. Interlock between the exhaust fan and heater fan.
