Low shower pressure is a common problem for most households. In New Zealand, a majority of old homes have low-pressure hot water systems. Poor shower pressure is caused by a number of issues, often more than one. If you have a low-pressure hot water system, you need 20mm copper pipework in the shower mixer for best results.
What is low-pressure or a low-pressure hot water heater?
Low-pressure refers to the type of tank that you have. Low-pressure hot water heaters are made from copper usually, and some are available in steel. The maximum pressure rating is usually 7.6m of head or 76kPa. Many hot water heaters have less than this rating.
What is High Pressure or Mains Pressure?
High Pressure or Mains Pressure refers to the rating of the tank. High-pressure tanks are capable of around 1000 kPa; not many are set at this pressure because an installation requirement is to put a pressure limiting valve on the line restricting the pressure to 500 kPa. This is still higher than low pressure at 76 kPa. Mains Pressure is a term used years ago before limiting valves were installed in tanks.
Low shower pressure or shower flow is sometimes due to a water tank mounted on the hot water cylinder or in the roof, a pressure reducing valve might be installed on the hot water cylinder with a short vent pipe.
Can I use a High or Mains Pressure Shower Mixer on a Low-Pressure Hot Water System?
No, the high-pressure shower mixer has small ports for reducing the flow of water. A low-pressure shower mixer has large ports for getting as much water as possible to the shower.
Southern Plumbing can help you determine if there are any faults with the current system. We can check for faulty supply tank, faulty mixer or rose, blocked pipes, etc. We have found all kinds of obstructions in pipes and mixers, insects, rubber washers, and whatever comes through the water supply. You can contact Southern Plumbing on 0800 484 353 for checking low shower pressure.