Low level, back to wall and wall hung toilet pans all use low level cistern – what this means is that the cistern remains exposed with a low level pan but is concealed behind a panel or wall for use with back to wall and wall hung toilets.On a close coupled toilet the cistern is bolted directly onto the toilet pan to form a single unit. This is now the most popular type of bathroom toilet as this design will hide more pipework than low or high level toilets. They are not quite as neat as a back to wall or wall hung toilet but are the next best option.
As the cistern and pan are bolted together they cannot be positioned independantly of each other. This can be a slight disadvantages if the bathroom soil pipe opening is positioned in the floor as the final position of the toilet will depend on the position of the soil pipe in the floor – if the pipe is 6 inches away from the wall the cistern will end up 6 inches from the wall.
There are some pan connectors that will partially compensate for this problem but sometimes the only option is to build a small, solid shelf at the back of the cistern to bridge the gap to the wall. If the soil outlet is in the floor but near he wall or if the outlet passed horizontally through the wall then there are no problems using a close coupled bathroom toilet.
Because regulations have been introduced to make new bathroom toilets flush with less water, cisterns can now be made much narrower than previously which has lead to some very compact designs being made available. These regulation changes also allow the use of new flushing mechanisms which are generally quieter in operation than the old syphons and work at the push of a button.
The downside of these new regulations is that the flushing performance of new bathroom toilets can be inferior to older models that have larger cisterns.
Most bathroom toilet designs now available in the UK do not require an external overflow making installation quicker, easier and neater.