Weil-McLain 94 Series Manual page 40

Weil-McLain 94 Series 3 Water and steam boilers —
Maintenance and troubleshooting
If gauge glass breaks, close off both gauge cocks
and loosen the glass retaining nuts to remove gauge
glass. Replace broken gauge glass with new gauge
glass made of heavy-walled Pyrex. DO NOT USE
THIN GLASS TUBING.
Checking the relief valve
1. Manually open the safety valve once each year by pulling
the valve lever or handle and allowing a small amount of
steam to escape.
2. Be sure that the valve reseals properly and does not leak.
3. If the relief valve sticks or appears to be clogged, replace
immediately.
Automatic air vents
1. With the system filled with water, loosen the air vent cap
slowly so that particles of dirt or scale are not deposited on
the valve seat by the escaping air.
2. Should dirt or scale lodge on the valve seat, causing it to leak,
remove the cap and press the inner stem with a screwdriver
or other tool to permit water to flush the valve seat clean.
3. Release the stem quickly and replace the cap.
4. For normal operation and venting, unscrew the cap at least
two turns.
40
for Gas, Light Oil, & Gas/Light Oil-Fired Burners
(continued)
Troubleshooting — steam boiler priming
or foaming
1. Foaming or priming in a steam boiler can cause large quanti-
ties of water to pass into the steam mains, resulting in violent
fluctuations of water level in the gauge glass.
2. This trouble may be caused by dirt, oil, or other impurities in
the boiler water, too high a boiler water level, a high overload
on the boiler (i.e., the sudden release of boiler steam pressure
into the mains by action of fast operating valves), or the ad-
dition of too much boiler water treatment.
3. With serious foaming or priming, stop the burner and de-
crease boiler load.
4. Then alternately blowdown and slowly feed fresh water
several times.
5. If trouble persists, it may be necessary to skim the boiler one
or more times.
Troubleshooting —relief valve opens
frequently or weeps
1. Expansion tank may be water-logged in it closed type (air-
head type)
2. Bladder or diaphragm-type expansion tank may have punc-
tured membrane or may have incorrect charge pressure —
follow tank manufacturer's instruction to troubleshoot and
set charge pressure.
Part No. 550-110-275/1018