Taking a boiler out of service is both expensive and disruptive. It can leave a building without heat, hot water, or steam for days, meaning lost production and unhappy customers or tenants. That’s why it pays to schedule boiler maintenance some time out, preferably for shutdowns or holiday periods. Many facilities make this an annual event, so the manhole and handhole boiler gaskets as well as the seals used in pipe flanges need to last at least that long.
- Don’t assume any rubbery material will do the job. It won’t. Buy good quality boiler seals from a reputable supplier. (Look for those made from EPDM as they hold up well to steam.)
- Clean the surfaces to be sealed thoroughly. The new seal should contact only the metal surfaces, not scale, corrosion, or scraps of old seal. Take care to avoid scratching the metal surfaces though as that will create a leak path.
- Avoid using any adhesives, sealants or anti-seize compounds on the seal or flanges. These can lower friction and allow the seal to move as the joint is tightened.
- Center the seal in the flange. This ensures clamping loads are distributed evenly across the surface. Not doing so creates areas of high and low load that reduce gasket life and let leaks form.
- Minimize the surface area of the seal exposed to atmosphere. Hot air leads to oxidation of the seal material, quickly reducing it’s life. If necessary, add shields to protect against hot air.
- Don’t overtighten the joint. This accelerates the process of the material taking a compression set and will lead to premature failure.
- Excessive heat and pressure shorten seal life. Temperatures and pressure above 380°F and 180 Bar should be avoided.
- Never reuse old gaskets. The material will have taken a compression set.
It’s worth investing time and money in buying quality boiler seals and fitting them carefully. When the job’s done properly the seals should function as intended for at least twelve months. That reduces the chance of premature failure, which would almost certainly require an unplanned, and expensive, shutdown.