There are many reasons why the header tank is overflowing: Issues with pump over run. Faulty coil in the hot water tank. Ball valve needs repairing or replacing.

Why does my header tank keep overflowing?

The most common cause of an overflowing header tank is a fault with the float mechanism, which may not be rising to the correct level and therefore not stopping the supply of water to the tank. This causes it to overflow through the outlet pipe (causing that cascade of water!).

Why is my hot water tank overflowing?





One of the most common causes of excess pressure in a water heater is simply having the temperature set too high. Since water expands as it’s heated, higher-temperature water occupies more volume, which, in the confines of a water heater, results in increased pressure.

Why does my cold water tank keep overflowing?

The most common reason for a cold water tank to overflow is a faulty ball valve. This valve controls the level of water in the cistern via a plastic float which sits on the surface of the water.

How much water should be in a central heating header tank?

The elevated water level must be at least 25 mm / 1 inch below the overflow.

Why does my expansion tank keep filling up?

Some tanks fail when a leak develops in the diaphragm. This usually causes the tank to fill with fluid and become “water logged.” You can check for this by pressing in the stem of the Schrader valve. If a stream of liquid comes out the tank is toast.

How much water does a header tank hold?





Usually 50 gals/bathroom of stored water is adequate, if you’re going to fit a pump then this would be the mninimum requirement depending on pump capacity.

How do I turn off the water in my header tank?


Quote from Youtube video: What you can do is you can put a piece of water across the top of the tank. And you can mend it a on the ball valve. I'm actually going to use a wedding stuff.

What pressure should a header tank be?

0.1 bar

If a header tank is located one metre above your shower head, the water pressure from your shower will be 0.1 bar. This is generally the minimum requirement for an adequate shower. Mixer showers, many of which are designed to perform well under lower water pressure, are the best solution for gravity fed water systems.

What happens if expansion tank pressure is too high?



If the pressure is too high, it can wreck even a new expansion tank. Too low of psi, and the bladder will never “squish” to take up expansion. The psi on the in line psi after the PRV, and the precharge on the expansion tank should be the same.

Why is water coming out of my expansion pipe?

Overflow pipe dripping outside



So, in summary, if you see an overflow pipe leaking outside, the likely cause is an overflowing toilet cistern, cold water or central heating feed and expansion tank. Or it could be your boiler overflow pipe dripping due to a faulty combination boiler.

How often should you drain expansion tank?

Water is not very compressible and only a small air cushion is available to absorb the system pressure. It cannot absorb as much pressure from the system and so the system PSI rises, possibly triggering the pressure relief valve. Draining the expansion tank should be done periodically, usually once or twice a year.

How do I know if my expansion tank is waterlogged?



If in 8-9 minutes of boiler operation (we mean that the burner or heat source is operating) the pressure gauge at the boiler reads a pressure within 10% of the spill pressure of the pressure relief valve on the boiler then the expansion tank is surely waterlogged and needs to be drained and re-charged with air.

What happens when expansion tank fails?

Oftenthe diaphragm dividing the two systems will fail, causing the two systems to become one. When this happens, the expansion tank turns into a “dead leg” that will eventually cause damage and premature failure to your water heater.

How do you bleed a boiler expansion tank?

3 Answers

  1. Turn off the valve that auto-fills the system from your cold water line.
  2. If you have one, open a valve or bleeder on the top of your expansion tank. …
  3. Open a drain valve and drain a suitable amount of water.
  4. Close drain valve and re-open valve you closed in step 1.