UNITED FIRE SYSTEMS -
NITROGEN-
PAC™
MODEL SC-W
INSTALLATION, COMMISSIONING, AND MAINTENANCE MANUAL
REVISION 1.01 MAR 2021
– P/N 30-NPWICM-000
67
IMPORTANT
To prevent inadvertent operation of sprinkler valve or actuation of low air signal,
ALWAYS
close Model PVA ball valve
BEFORE
removing drain plug or strainer retainer.
5.4.5. Drainage of Accumulated Water at Model PVA Purge Vent Assembly.
Refer to
Figure 39.
Residual water can
accumulate at PVAs, possibly blocking purge flow. Periodic removal of this residual water permits purging to take
place with no obstruction.
(a) If open,
CLOSE
PVA ball valve.
(b) Hold PVA so that torque applied to drain plug does not move PVA.
(c) With suitable wrench, remove drain plug.
(d) Allow sufficient time for accumulated water to drain.
(e) Apply Teflon tape to male threads of drain plug. (Recommended tape = Hercules Megatape or similar; 1/2 inch
wide x 3.5 mils thick.)
(f) Replace drain plug, tightening with suitable wrench.
(g) If TAP device is installed, open ball valve.
(h) If TAP device is not installed, open ball valve only if purging is required.
5.4.6. Replacement of Strainer at Model PVA Purge Vent Assembly.
Refer to
Figure 39.
(a) A clogged strainer may inhibit purging. Replace strainer when clogged.
(b) If open,
CLOSE
PVA ball valve.
(c) Hold PVA so that torque applied to drain plug does not move PVA.
(d) Apply suitable wrench to hex on strainer retainer. Do not remove square plug.
(e) Remove and retain the strainer retainer.
(f) Examine rubber seal on strainer retainer. If damaged during removal, leakage may occur.
(g) Remove old strainer.
(h) Insert new strainer. Ensure strainer remains fully inserted.
(j) Tighten strainer retainer wrench-tight.
(k) If TAP device is installed, open ball valve.
(m) If TAP device is not installed, open ball valve only if purging is required.
5.5 Maintenance Parts
Table 12
Maintenance Parts
Description
UFS P/N
Intake Filter, Compressor
00-100005-558
Element, Particulate and Coalescing Filters
30-500002-101
Element, Water Separator
30-500002-301
Element, Enclosure Intake Filter
32-000043-002
Element, Exhaust Fan Filter
30-500200-002
Screen, Strainer, Model PVA
30-500003-301
Summary of Contents for Nitrogen Pac SC-W
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