A bathroom fan dripping water indicates three potential problems. Water getting in from outside, a plumbing issue such as leaking pipes in the ceiling or condensation build up. This post will give some possible reasons why this is happening from an electrical standpoint.
Bathroom Fan Fault Finding
A bathroom extraction fan is typically a small fan recessed into the wall or ceiling.
Its purpose is to ventilate and remove smells from the bathroom. If located on the wall, the bathroom fan may vent directly outside where the air can escape. Typically the outside component has a waterproof barrier or flashing to prevent water from coming back inside.
There will be a length of duct leading from the fan to an outside point where the air can escape. When the fan is turned on, it will push air outside through the duct.
The duct is typically taped to both the inside and outside fan grills.
Modern bathroom fans are typically wired in 1mm cable. As bathroom fans are located in a wet area, they must be on protected by a residual current device (RCD). The fan itself must be the appropriate IP rating for the location it is installed. This ensures that water can’t penetrate any electrical parts of the fan.
With basic knowledge about bathroom fans let’s look at the three reasons why it might be dripping water.
Bathroom Fan Dripping Water? – Reason #1
Water Getting In From Outside
Likelihood: Moderate – can water get in from outside? Is the outside fan grill watertight?
If the outside fan grill is not water tight, then water may be able to get inside after heavy rain. If the outside fan grill is damaged or worn away then water might be able to get inside. This is more likely to happen if the fan grill is located on a wall compared to a soffit. Water would track inside before dripping out of the bathroom fan. If water gets into the fan duct it can affect air flow or cause the fan to stop working.
Bathroom Fan Dripping Water? – Reason #2
Plumbing Problem With Pipes In Wall Or Ceiling
Likelihood: Moderate – depending on the condition of the plumbing
A leaking pipe in the ceiling could cause water to drip down through the bathroom fan. If this is the case there might be other signs of water damage such as dampness or discoloration in the ceiling. It is a good idea to make a trip into the ceiling cavity to rule out whether this is the cause.
Bathroom Fan Dripping Water? – Reason #3
Condensation Buildup Due To Obstruction, Bends And Creases In Ducting
Likelihood: Moderate
If the fan isn’t strong enough or the ducting has several bends and creases then moisture can have trouble escaping.
This can cause moisture to back track and drip out of the fan when the fan is turned off. For the fan to work properly there needs to be minimal bends and creases in the ducting (ideally zero). This ensures that air can flow without obstruction. To check if this is the case, you should be able to check the condition of the ducting in the ceiling.
Electricians Perspective
Water getting in from outside due to poor weather tightness, leaking plumbing, and creased ducting are all reasons why a bathroom fan would drip water in our experience. Checking the outside fan grill for damage or looseness and checking the ducting in the ceiling should give clues as to why this is happening.
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