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HONEYWELL MODEL 700/800 SIGNAL PROCESSOR AND VIEWING HEAD
66-2069—02 8
Fig. 6. ASSY786 Viewing Head Plug Assembly with C330S.
Protecting the Viewing Head Cable
(Connector Series)
Note that when the wiring needs to meet Class I, Division 2
requirements for use in hazardous locations and when conduit
is used, the conduit must be sealed where the cable passes
from the hazardous location to the non-hazardous location in
order to keep potentially hazardous gases from being
conducted into the non-hazardous area.
Viewing Head Connector LED
Indicators
The viewing head connector has orange and green LEDs
which can be viewed from the rear of the connector when the
connector cover is removed.
The green LED displays the pulses out of the viewing head
and the orange LED shows that the self-checking signal from
the signal processor is reaching the viewing head. If power is
on at the signal processor, the orange LED should flash at one
pulse per second, even if the viewing head is not plugged in.
This is helpful in troubleshooting.
With no flame signal present, the green LED will flash one
pulse per second in step with the self-checking signal. The
viewing head is sending back an ID pulse; this is part of the
self-checking system. When a flame is present, the green
LED will flash at a rate proportional to the flame signal, except
when the pulses are interrupted once per second for the self-
check pulse arrival at the viewing head. The pulse rate of the
green LED flashes can be used for aiming the viewing head.
NOTE: The LED indicators are provided for alignment
and troubleshooting only. Reinstall cover with
gasket correctly in place at all times, and ensure
that connector coupling is tightened securely.
This gasket and cover must be installed properly
to maintain NEMA rating.
Viewing Head Mounting and Sighting
Mounting is 1/2-in. NPT (F) for all viewing head models with a
1/4-in. NPT (F) purge air connection. Before beginning
installation, determine the best location for mounting the
viewing head based upon the following factors:
Viewing Head Mounting Block
The S70X viewing heads are held firmly in place in their
mounting blocks by two galvanized steel latches. The S80X
viewing head is secured in its mounting block by a friction
twist-lock. Refer to the ACCESSORIES section for part
numbers.
Pressure
The S70X viewing head lens will withstand 50 psi (3.4 bar)
while the S80X lens will withstand 90 psi (6.2 bar), provided
the compression ring on the purge air adapter is tightened
properly. If the lens assembly is exposed to greater pressures
through the sight pipe, then an isolation unit must be used.
Honeywell isolation units with purge air entrance are available
as accessories; ISO-UNIT, ISO-UNITSS, ISO-UNITHPGT.
Each has a quartz window, two 1-in. NPTF connections and a
1/2-in. NPTF purge port.
Temperature
The case temperature of the viewing head housing must not
exceed 185°F (85°C) while the standard Delrin mounting
block must not exceed 180°F (82°C) continuous service. Care
should be taken to ensure the case housing and mounting
block temperatures do not exceed these values.
Purge air will help reduce conducted heat through the sight
pipe and flange. A heat insulating Ultem replacement viewing
head mounting block is available for both the S70X/S80X
models (part numbers 700UA and 800UA) with a continuous
service rating of 320°F (160°C) as well a 1/2-in. NPTM Ultem
nipple (part number R-518-13) or an Ultem locking coupler
adapter (R-518-PT13 or R-518-PT13L) to reduce the
conducted heat, but direct radiation can cause the housing
case temperature to exceed limits. If the ambient heat (direct
radiation) is excessive, then an air cooling canister with vortex
cooler should be considered or alternately a fiber optic
extension. The extension uses a fiber optic cable assembly
between the sight pipe and the viewing head, allowing the
viewing head to be placed further away from the heat source.
Refer to the Fiber Optic Manual 69-2683 or contact your
distributor or the factory for assistance with fiber optic
selection and pricing.
Purge Air
Use a flexible air supply line, to allow for repositioning of the
viewing head and sight pipe until a final and permanent
M35140