Plumbing problems

It has become common to completely hide WC connections behind panels and boxing. In commercial buildings it may be possible to access the plumbing connections, cisterns, etc. from a service area on the other side of the WC area. In domestic situations there is often simply no access whatsoever to maintain the hidden and often seriously built-in plumbing connections and mechanisms.

Some plumbing connections seem to be fraught with problems. The classic problem is sealing a flush pipe to the spigot at the rear of a WC pan. Some connectors fit inside the WC pan itself, while others seal around the spigot. Either way, this connection often leaks.

Patent connectors such as the Multikwik shown in figure 3 are extremely reliable. If the correct connector is fitted according to the manufacturer's instructions, there should not be a leak problem. After fitting, run a dry finger around the connector near the pan and it should remain dead dry after flushing the WC. Even the tiniest of drips means you will need to refit the pan connector and check again for watertightness. The pan spigot needs to be clean and free of any imperfections that could prevent a good seal of the connector. It is less likely for leaks to occur on the soil branch side of the connector.

Figure 1: A difficult to maintain WC suite – all you can see is the cistern handle. To access the cistern of this close-coupled suite you need to demolish the boxing in – a job you see in progress, as its tiling has already been removed. Behind this WC you would also eventually discover a soil stub stack, and various inaccessible connections to it from basin wastes and so on

Figure 2: A selection of flush pipe connectors. The black rubber collar fits on the outside of a spigot at the back of a vitreous china pan. Such a fitting is notorious for leaking. You will find all manner of sealants, jubilee clips and other efforts to seal the connection. Drips at the back of pans create rot problems. The other 2 plugs also hug around the flush pipe but push inside a socket at the back of the pan. In the author's experience, the rubbery internal plug (bottom of picture) achieves the most leak-free connection. The flush pipe needs to be securely fitted in position by brackets as it can vibrate and disengage from the pan. Leaks will result

Figure 3: A flush pipe from a high-level cistern fits into the rear of a vitreous china WC pan using an internal rubber plug – a really reliable connection – and the flush pipe is stabilised using wall clips. A Multikwik is used to connect the pan to the cast-iron soil stack branch – neatly pointed up using cement and sand bonded with the help of PVA

Figure 4: Note the rubber sealing ring. There is the smallest chance of debris lodging where we find a sharp raised angle at the corner mitre on the inside of the bend. A tiny pond could develop just the other side of the sealing ring at X (see figure 5), which could sometimes promote a blockage. 

Figure 5: An MKB3190 Multikwik. Note the rubber sealing rings. Looking into the pan connection end, you will see the fawn rubber washer. The lubricant supplied must be used to help push this end of the connector onto the WC pan spigot