Hi All,

I am in need to of some help with regards to identifying what is causing water dripping (not the little water in the pic) from the water heater external drain pipe (which has caused high water bills in the past few months)

I have attached a pic, with some additional pics for different angles to show you my water heater setup

Based on the numbers marked in the image, I have noted below the respective valves and pipes to the best of my knowledge but I am new to this, so please do correct me if I am wrong:

1. Cold Water Inlet (rising from below the floor)

2. Power Supply

3. Filter/Non-Return Valve

4. Limiting Stop Valve

5. Cold Water Expansion Valve EVT

6. Is this blue tap a gate valve?

7. What is the purpose of this pipe (its cold)

8. Cold Pipe, coming out of the top of the cylinder and draining down to outside

9. Hot pipe, coming out of the top of the cylinder and supplying hot water to the house.

So the when the mains are open at the water meter, the meter is ticking slowly but continuously. I noticed that the near the waste water outlet (outside the house) there is a small pipe dripping water continuously.

I narrowed it down to the water heater area and this external drain pipe connects to the pipe 8. (in the pic) and the EVT (5.)

When I close the filter (3.) then the supply to the water heater stops, i.e. the hot water in the taps also stop and the dripping out of the drain pipe stops too.

Is it the cold water expansion valve (5.) which is faulty or is the heater overfilling internally to cause it to drain excess cold water?

NOTE: There is no visible leakage anywhere around or above or below the water heater.

Any help would be super great as I would like to DIY this if its possibly a minor issue.

Thanks,

Sheldon