The noisy central heating pump may be a result of airlocks. Airlocks are pockets of air that form in the circulating water and cause the central heating system to make a gurgling sound, which may make the pump noisy. An excellent way to prevent this is to bleed the radiators. This simple procedure is about freeing trapped air from the system In general, the causes of banging noises from a baseboard heating system can be caused by: 1) Air is trapped in the line, which needs to be bled out. 2) A pipe to or from this baseboard radiator that is running through a hole in a wall, etc. that is too tight, which doesn't allow sufficiently for the pipe's thermal expansion. Kettling can be a serious problem that should be looked at by a gas safe engineer, but common causes include: Limescale build-up. Boiler overheating or faulty. The most common reason your boiler is making rattling sounds is there are loose bolts in your boiler. But these unusual noises can mean other things. Car radiator leak. If you have a car radiator leak, your car radiator sealant may have failed or peeled away entirely in places, causing the all-important coolant to leak out. Signs that you have a radiator leak include: You can see radiator fluid leaking underneath the car; The radiator is making a hissing noise; The radiator looks rusty Radiators make a lot of noise. Some of it is bad, but a good majority of it is totally normal. If you notice one of the above sounds coming from a radiator or the pipes surrounding it, it's likely time to make a change. Clean and wipe dirt off the fan and blades – build-up can cause a flutter or wobble to occur. Make sure it spins freely, and blades aren’t damaged. If the fan is damaged or noisy, consider replacing it with a quieter one. There are several fans with quiet motors on the market manufactured to decrease noise. 4. Unless . . . have you determined if they are steam radiators (one pipe, coming in) or hot water radiators (two pipes: one coming in, another coming out). I think this is why the behavior is so strange to me. I've only had hot water radiators before, and looking now see that these must be steam radiators. Initial Sounds: Air bubbles: As you maneuver the oil heater around, the oil can shake, which essentially causes bubbles to form due to the air coming into its space. When it gets heated up, the bubbles get larger and burst, making a clicking noise. The good news is that it will stop once the heater is turned off and can be solved when you place Yes, some water heater hissing sounds are an indication of a bigger problem that will, unfortunately, require repair or replacement of your water heater. However, there are some reasons why your water heater may be making a hissing sound that is completely normal or only requires a small fix. We take a look at each of the reasons why your hot Airlock. Central heating pump humming noises are most commonly caused by an airlock. This is when air builds up in the pump and causes a blockage. To stop the humming and release the air, many central heating pumps have a bleed screw which can be simply turned to rid the pump of excess air. uZQi3U5.