DeVilbiss DeVO/MC44-90 - Manifold Assembly

SECTION 7
SERVICE INSTRUCTIONS
(A) Compressor reed valves, teflon ring,
or the compressor itself may be
defective.
(B) There is a severe leak in system.
(C) One or more of unit filters may be
occluded.
K. Manifold Assembly
The manifold assembly is located on the front
of the vertical divider and has two externally
mounted valves, the 4-way and purge (see
Fig. 16). These valves can be removed
separately for cleaning or replacement when
necessary. The base of the manifold assembly
does not have to be removed in this case.
The manifold base contains internal check
valves, an orifice, and a pilot accumulator
cavity with check valve. If troubleshooting
procedures reveal that a unit malfunction is
the result of a failure of one of these check
valves or any other internal problem, then the
entire manifold base must be replaced. Do
not take the base of the manifold apart or
attempt to change any internal components.
To remove manifold:
1. Unplug unit from wal! outlet.
2. Refer to service instruction B to open the
front cover.
3. Cut the cable tie clamp and remove the
center oxygen outlet tubing from the top
of the manifold assembly (8 Fig. 16).
NOTE: Care must be taken to avoid applying
a bending force which could result in
breakage of the fitting on the manifold when
disconnecting this tubing.
4. Loosen hose clamps and remove the left
and right sieve bed oxygen supply hoses
from the top of the manifold assembly
(7,9 Fig. 16).
5. Loosen hose clamps and remove the left
and right sieve bed hoses from the
bottom of the manifold unit (16 Fig. 11).
6. Disconnect the wires from the terminals
on the four way and purge pilot valves
(4,14 Fig. 16).
7. Remove the two manifold base mounting
screws located at the upper left and lower
right face of the manifold base.
8. Carefully pull the manifold assembly away
from the vertical divider a short distance
10/87
22
to gain access to the air inlet fitting on the
back of the manifold (see Figure 20).
9. Loosen hose clamp and remove the
compressor exhaust hose from inlet
fitting (3 Fig. 20) and remove manifold
assembly.
NOTE: If a replacement manifold is not to be
installed immediately, the sieve bed hoses
must be tightly sealed to prevent bed
contamination.
To replace manifold:
1. Remove the 4-way and purge valves from
defective manifold and install them on
the new manifold base.
2. Remove protective covers from hose
fittings on replacement manifold unit.
NOTE: Care should be taken to avoid scratch-
ing or otherwise damaging the fittings.
3. Attach the compressor exhaust to the
inlet fitting on back of manifold and
secure with hose clamp.
4. Position the manifold assembly on the
vertical divider and secure with two
screws in the upper left and lower right
corners.
5. Install first the right and then the left
sieve bed hoses on the fittings at the
bottom of the manifold unit and tighten
hose clamps.
6. Install the smaller (1/8” (3.2 mm) 1.D.)
oxygen tubing on the center fitting at the
top of the manifold and secure with a
new cable tie clamp.
7. Install the right sieve bed oxygen supply
hose to the left manifold fitting, and the
left sieve bed oxygen supply hose to the
right manifold fitting. Tighten hose
clamps.
NOTE: Care must be taken to insure that the
right (inside) sieve bed hose is connected to
the left manifold fitting, and the left
(outside) sieve bed hose on the right
manifold fitting.
8. Connect the electrical wire pairs to the
pilot valves of the 4-way and purge.
NOTE: The yellow-brown wire pair connects
to the purge pilot valve (upper unit), and the
violet-brown wire pair connects to the four
way pilot valve (lower unit).