What sort of a drain pipe is this?

Question

I dont even know if drain pipe is the right word. We have this little pipe jutting out of the wall in our back yard.

It keeps dripping water. Its a new unit/apartment in Australia and the builder is now no where - so we are on our own.

First we thought it was the water heaters outlet, because the builder said so. But the water dripping out is cold. Then we noticed it will only drip when our washing machine is draining its water into the trough. Clothes washed with cold water. Doesn't look like all of the water is getting out either, but only a glassfull.

1) Should we be worried about it ? 2) How do I fix it.

Answer 1

If you only notice it draining when the air conditioning cooling unit is on, my guess would be it is the condensate drain for the evaporator coil.

Answer 2

Typical of a condensate drain, I'd be surprised if you can't trace the thing back inside and see where it connects (run something stiff-but-flexible up the pipe and listen inside if not otherwise obvious.) Might be from an A/C unit, a condensing furnace or hot water heater, etc. In freezing climates safety overflows are normally prohibited from a placement like this (due to potential ice plugs), but that is probably not a concern for your area so it could be that, as well.

Placement right next to a drain grate suggests that there should not be too much concern with a small amount of water coming out of it.

You might set an empty can under it when you are done with the washing and check it before the next washing, just to see if it is in fact running at other times.

Does your washing machine set in a tray? (An arrangement to minimize the effect of a leak in the machine, essentially a very localized floor drain.)

Answer 3

A pipe like this is often a safety overflow from a central heating boiler.

I had the same problem, dripping cold water from a pipe like that in a new built house. It was eventually traced to a wrongly fitted safety valve on the expansion tank beside the gas boiler. I was told by the plumber that, if left, the heating pump would eventually fail.

After some haggling, the builder did pay for both the valve and the pump to be replaced and the dripping stopped.

Incidentally, if it is a new build property, ask around your neighbours. There were half a dozen similar faults in houses built at the same time by the same builder. Collective bargaining helps in getting your money back.