Honeywell MP-953D Installation And Maintenance Manual page 4

REPRAIR AND ADJUSTMENT PRC%EDURES FOR HONEYWELL MP-953B, M%-95iD,
OR MP-953P PNEUMATIC OPERATORS USED ON ARMSTRONG HUHIDIFIERS
REPLACING STEM SEALS
There are stem seals in the bonnet assembly to prevent steam
leaks around the stem.
followed if these seals need to be replaced.
Remove the pneumatic operator in accordance with
Section I.
Remove the bonnet assembly (15) from the humidifier
cap.
3. Remove the yoke assembly (36), stem adapter (17A), and
stem nut (17) from the stem (16).
4. Remove the packing gland (18) from the bonnet (15).
5. Push down the valve stem (16), then press it back into
Repeat if necessary to loosen the seals (20)
place.
and spacer (19).
Remove the seals (20) and spacer (19).
6.
With the stem (16) in the bonnet (15), place two new
7.
seals (20) with the spacer (19) between them, onto the
stem. The open end of BOTH seals (with spring showing)
should be toward the valve.
Carefully guide the seals into place in the bonnet
a.
Slide the packing gland (18) over the stem and
(15).
turn it into the bonnet.
securely.
Turn the bonnet assembly (15) into the humidifier cap,
9.
and tighten securely.
Install the pneumatic operator in accordance with
10.
Section II.
CHANGING OPERATOR SPRlNGS
Remove the pneumatic operator in accordance with
Section I.
Remove the six cover screws (31) from the operator
2.
cover (33).
3. Lift the cover (33) from the frame (29).
Remove the hex nut (34) and washer (32) from the
4.
support (24).
5. Remove the follower (38) and diaphragm (21) from the
frame (29).
6.
base (26).
7. Remove the base (26).
Carefully remove the cup (28) and support (24) -- avoid
a.
damaging the rolling seal (22).
Remove the old spring (30) and replace it with the new
9.
one.
Insert the support (24) through the center of the cup
10.
frame.
Attach the rolling seal (22), and press the
support back into place.
The following steps should be
Tighten the packing gland
3