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DISaSSEMBLy aND CLEaNINg pROCEDURE
The PIRVOLHV should be inspected periodically to ensure
that its performance is not impaired by fouled optics or by
clogging of the sample draw cup or hydrophobic filter.
Inspection and/or periodic maintenance involves three
different areas.
IMPORTANT
Remove power before disconnecting and
removing the PIRVOLHV for maintenance.
Sample Draw Cup.
Perform a visual inspection of the
sample draw cup and associated plumbing, and clean
as required. External filtration of sample stream is
recommended.
hydrophobic Filter.
The flow of gas through the
filter can be inhibited by an accumulation of mud or
other contaminants. To inspect the hydrophobic filter,
disassemble the PIRVOLHV as described below. If the
filter appears to be fouled, replace it.
Optics.
Cleaning of the optical surfaces is required only
if an optical fault is indicated (1.0 mA current output signal
from the PIRVOLHV). This procedure is most easily
accomplished on a bench.
Required materials: Clean, flat work surface, foam tipped
swabs (no cotton), isopropyl alcohol, screwdriver.
CAUTION
The PIRVOLHV contains semiconductor devices
that are susceptible to damage by electrostatic
discharge. An electrostatic charge can build
up on the skin and discharge when an object is
touched. Therefore, use caution when handling
the device, taking care not to touch electronic
components or terminals. If the electronics
assembly is removed, it should be placed in an
anti-static bag or box while stored or transported.
A static safeguarded work area is highly
recommended (if available) for disassembly and
cleaning of the PIRVOLHV.
1. Remove the sample draw cup from the front of the
PIRVOLHV by pulling it straight off the electronics
assembly (no tools needed). See Figure 12.
2. Perform a visual inspection of the sample draw
cup and associated plumbing, and clean as
required. Also inspect the two O-rings inside the
sample draw cup and clean, lubricate or replace
as required.
3. Loosen the two captive screws on top of the
mirror assembly (Figure 12) and remove the
mirror assembly and hydrophobic filter from the
electronics assembly.
4. Thoroughly douse the interior of the mirror
assembly as well as the foam tipped swab
with isopropyl alcohol. Use the swab to gently
cleanse the surfaces of the reflecting mirrors
inside the mirror assembly. After cleaning with
the swab, flush out the mirror assembly using
a liberal amount of isopropyl alcohol. Tip the
mirror assembly with mirror openings downward
to remove accumulated isopropyl alcohol and
particle contaminants. Repeat the alcohol flush
to remove any remaining contaminants. Allow the
mirror assembly to air dry in a dust-free location.
IMPORTANT
Do not insert any sharp object into the mirror
assembly. Scratching of the mirrors will void the
PIRVOLHV warranty. Do not use cotton tipped
swabs or buds as they are likely to leave fiber
residue.
5. Clean the two windows on the electronics
assembly using the procedure described above.
When the mirror assembly and electronics
assembly are thoroughly dry, proceed with
re-assembly.
6. Slide a new hydrophobic filter over the end of the
mirror assembly, then carefully seat the mirror
assembly and hydrophobic filter against the base
of the electronics assembly. Be careful not to
crumple or fold the hydrophobic filter.
7. Tighten the two captive screws on the top of the
mirror assembly. Tighten the screws evenly. Do
not over-tighten (6 inch-pounds recommended).
8. Slide the sample draw cup back onto the
PIRVOLHV.
9. Check for leaks around the PIRVOLHV sample
draw cup.
