Water Gauge Accuracy
- Your water level gauge glass may not be reading properly if it is leaking. The water level may be higher in the glass than in the boiler when the glass leaks around the top packing nut or top valve stem. This can lead you to think the water level is good when it is too low. The low water cut-off may be in safety shut down even though the level gauge looks OK.
Regularly scheduled maintenance will prevent gauge glass leaks. Advanced Boiler carries a complete line of gauge valves, glass, and gaskets.
Caring for an Out-Of Service Boiler
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There are two primary ways to care for an out-of-service boiler. These are usually chosen on the basis of whether freezing temperatures will exist while the boiler is stored and whether the boiler may be needed for service on short notice. The boiler can be stored dry or wet. In either case, it should be thoroughly cleaned before storage.
Dry Storage
The cleaned boiler should be thoroughly dried. Any moisture will cause corrosion on long standing. All lines to the boiler that could carry moisture back to the boiler must be blocked off. Remember, even air can carry moisture.
Moisture absorbing material may be placed on trays inside the shell at the rate of 2 lbs. of quick lime or 10 lbs. Of silica gel for each 1,000 gal. of capacity. Periodic inspections of the effectiveness of these materials are recommended during extended storage.
Wet Storage
The cleaned boiler should be closed and filled to overflowing using chemically conditioned water (condensate is purer than feedwater for this purpose). Caustic soda is often used for this treatment at a concentration of 450 ppm with an oxygen scavenger such as sodium sulfite at 200 PPM. Water pressure greater than atmospheric should be maintained during storage.
Grease and Boilers
- Grease or oil in a boiler is not good. It usually causes “priming” or “foaming,” and is usually visible on top of the water in the gauge glass. Remedy: Skim the water in the boiler before draining – refill and add soda ash to cut grease.
Pressure Gauge Slow?
- A “slow” pressure gauge indicates that its anti-syphon nipple is filled with scale and rust and its readings are inaccurate. Brass pigtail nipples are generally more trouble-free.
Hand-Hole Crabs Tight?
- After start-up, crabs should be re-tightened as pressure comes up and the gasket seats in. A loose crab on bottom or below water line can cause a boiler to drain on shutdown as steam pressure lowers to zero.
Scale Build-Up Insulates
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A Coating of scale is a coating of insulation.
It will:
– Lower the efficiency of a boiler causing it to use more fuel.
– Cause fire surface temperatures to rise beyond their designed temperatures.
– Insulate fusible plugs, greatly changing their melting temperatures.
Water Gauge, Is it Full or Empty?
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When no water level shows on a sight glass, you can quickly tell whether it is completely full or completely empty.
Hold a pencil against the far side of the sight glass tube at an angle of approximately 45 degrees. If the image of the pencil viewed through the glass appears to run across the glass and changes little no matter what the angle of the pencil, the glass is full.
However, if the image viewed through the glass runs up and down the glass at a sharper angle than the actual angle of the pencil, the tube is empty.
Check this difference with normal water level before an emergency by viewing through the sight glass above and below the water line. Thick wall tubing gives a less pronounced difference, but a real difference, nevertheless. A little practice will take away any uncertainty.
