Fault analysis of heat transfer oil boilers
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This post was last edited by adabruce on 2017-1-5 09:07. What are the consequences of not addressing pipeline blockages and water vapor intrusion in fuel-fired heat transfer oil boilers in a timely manner? Will it cause fuel injection in the expansion tank?
The pipeline is blocked; if the temperature continues to rise, it will cause the oil temperature in that area to become too high, accelerating its aging. If heating continues, the furnace chamber could be damaged. Excessive water vapor entering the system and a rapid rise in temperature can also lead to oil spraying.
I read on the internet that coal burning poses such risks. Our unit uses diesel, and it has an automatic temperature alarm that shuts off the burner once the temperature reaches its upper limit. Is this risk still present? I’m a beginner; please give me some advice. Thank you
The key factor for heat transfer oil is the flow rate; if the pipes get blocked and the flow rate drops too low, the oil becomes dangerous. Even shutting down the boiler due to an over-temperature alarm isn’t sufficient. In a normal heat transfer oil boiler, the burner should be turned off first, and only after the oil temperature drops should the oil pump be stopped. Once the pipeline is blocked, it means that both the burner and the oil pump stop working, and thermal inertia still causes damage to the oil.
That makes sense. So, if a pipe blockage results in low flow rates while the burner continues to burn, could this cause the heat transfer oil to expand, thereby posing a risk of oil overflow from the expansion tank?
There’s no problem with this; even if the heat transfer oil expands and causes overflow from the upper tank, it will flow into the lower tank. Unless there is a design flaw, meaning that the overflow pipe of the upper tank isn’t connected directly to the lower tank.
When the most water vapor enters, oil is injected into the expansion tank; then the oil temperature is lowered to remove the water vapor. Which pipe is blocked? The pipes of the furnace are blocked; an emergency shutdown is necessary. It seems the furnace is also close to reaching the end of its useful life ； The pipes inside the furnace are blocked, which is dangerous while it’s in use. The pipeline to the production area is blocked; the furnace has been shut down for inspection. No matter which type of pipe gets blocked, the furnace must be shut down and cooled down for maintenance – safety first!
As a supplementary point, when the pipeline gets blocked and an emergency shutdown of the boiler is required, it is necessary to open the high-level tank to allow cold oil to flow in, thereby replacing the hot oil inside the boiler and preventing damage to the coils due to high temperatures.