Unfortunately, it is not a good sign if you discover a build up of water on the floor by your furnace. In simple terms, something is wrong. However, it’s not all bad news and often swift action and a maybe call to a qualified furnace engineer can fix most problems before they become painfully expensive to solve. So, what are the most likely causes of this water leak and what will need to be done to fix the leak?
First, what type of furnace do you have. If it is a high-efficiency furnace, then it will most likely have a small PVC or metal tube attached to the vent pipe which drains collected moisture (condensation) from the unit. It could be that the tube has become blocked or has come loose. You can buy tablets for cleaning the condensation pipe, and if that fails, then best to call out an engineer as chances are, you may need some new tubing or firmer reattachment of the tube.
If the exhaust pipe which carries exhaust fumes from your boiler outside your home is the wrong size, it is possible that those fumes are condensing before they reach the outside, causing a build-up of water in the pipework, which is now overflowing/leaking from the system. This repair/fix definitely requires the services of a qualified furnace or HVAC engineer as it is likely they will have to fit a better-size tube or redesign the exhaust pipework.
The next culprit could be a faulty condensation pump. This is responsible for literally pumping condensed water from your unit outside. If the pump has developed a fault, this will not stop condensation from forming and leaking from your furnace.
Lastly, it may be a leaking humidifier that is causing the problem, and once again that will require the attention of a specialist heating engineer.
One thing to bear in mind is the age of the furnace, as the older it becomes, the more likely it will be that one particular fault is causing the problem. One of the best things you can do if your furnace has spring a water leak is give us a call, tell us where the water appears to be coming from, provide us with the make and model number of the furnace (if you can easily find this) and also tell us how old the furnace is. That way we can give you a clearer idea of what the problem is likely to be and also give you an indication of the cost involved to fix it before we come out to fix it.