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SECTION G: Maintenance
11. Check for piping leaks around pumps, relief valves
and other fittings. Repair, if found. DO NOT use pe-
troleum-based stop-leak.
Periodically
1.
Check relief valve. Refer to manufacturer's instruc-
tions on valve.
2.
Test low water cut-off (if equipped). Refer to manu-
facturer's instructions.
Preventive Maintenance
Schedule
The following is required procedure in all jurisdictions
which require CSD-1 and good practice for all MVB instal-
lations.
Daily
1.
Check gauges, monitors and indicators.
2.
Check instrument and equipment settings. (See "Post
Start-Up Check" on page 45.)
3.
Check burner flame. (Should see light blue flame at
full input rate).
Weekly
For low-pressure heaters, test low-water cut-off device.
(With heater in pre-purge, depress the low water cut-off
test button. Appliance should shut-off and ignition fault
light should come on. Depress reset button on front of
heater control panel to reset).
1.
Check igniter. (Resistance reading should be 42-70
ohms at ambient temperature.)
2.
Check flame signal strength. (Flame signal should be
greater than 1 microamp as measured at the 2 pins on
the upper left corner of the ignition control).
3.
Check flame failure detection system. (See "Post Start-
Up Check" on page 45.)
4.
Check firing rate control by checking the manifold
pressure. (See "Manifold Adjustment" on page 43.)
5.
Make auditory and visual check of main fuel valve.
Monthly
1.
Check flue, vent, stack, or outlet dampers.
2.
Test blower air pressure. (See "Blower Adjustment"
on page 42.)
3.
Test high and low gas pressure interlocks (if equipped).
(See "Safety Inspection" on page 44.)
Semi-Annually
1.
Recalibrate all indicating and recording gauges.
2.
Check flame failure detection system components.
3.
Check firing rate control by checking the manifold
pressure. (See "Manifold Adjustment" on page 43.)
4.
Check piping and wiring of all interlocks and shut-off
valves.
Annually
1.
Test flame failure detection system and pilot turndown.
2.
Test high limit and operating temperature. (See "Post
Start-Up Check," page 45.)
3.
Check flame sensors.
4.
Conduct a combustion test at full fire. Carbon dioxide
should be 8.0 to 9.0% at full fire for natural gas, and
between 9.0 to 10.0% for propane gas. Carbon monox-
ide should be < 100 ppm.
5.
Check valve coil for 60 cycle hum or buzz. Check for
leaks at all valve fittings using a soapy water solution
(while heater is operating). Test other operating parts
of all safety shut-off and control valves and increase or
decrease settings (depending on the type of control)
until the safety circuit opens. Reset to original setting
after each device is tested.
6.
Perform leakage test on gas valves. (See Fig. 40.)
7.
Test air switch in accordance with manufacturer's
instructions. (Turn panel switch to the "On" position
until blower is proven, then turn the switch to "Off."
8.
Inspect burner.
As Required
1.
Recondition or replace low water cut-off device (if
equipped).
2.
Check drip leg and gas strainers.
3.
Perform flame failure detection tests.
4.
Test safety/safety relief valves in accordance with
ASME Heater and Pressure Vessel Code Section IV.
52
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