Water isolation before plumbing repairs

Drain off valve
Before and after radiator the installation of a drain off valve


A dry start to plumbing repairs.

Water isolation becomes second nature to a seasoned plumber before attempting the removal or opening of a joint. When carrying out repairs the water retained within pipework often requires removal, especially if the repair includes soldered joints. A soldered joint requires a clean dry and water free surface in order to increase the temperature rise, this is crustal to the bonding process. However heat is not always required when closing joints, there are various methods to choose from that are appropriate to suit the task.


I’ve already isolated the water but it wont stop running.

Already isolated but the water is still coming, this often occurs when the opening is at a low level. If there is a floor above the rapid peace of the water being drained down will eventually slow down.  The correct method of isolation is essential to successfully restrain the water supply for leakage. In most cases, plumbing repair that is not central heating relate can be isolation at the stop cock.  Water retention can easily be relieved simply by opening a hot or cold tap depending on the work being carried out.  This must be done at the lowest level i.e. downstairs until the water runs dry.

Newbuild properties are often fitted with easy to use drain off points, they can found beneath the kitchen sink, easy access to drain the cold and hot water supply. Drain off points can also be incorporated as part of a radiator valve to increase speed whilst carrying out Central heating repairs.

When draining water from central heating pipework it can become stagnant or level and will not drain without a driving force ie pressure or a gradient to push it through.  A wet and dry vacuum can pull the water out, this will drastically speed up the prosses of draining down when carrying out repairs.   Emergency plumbing repairs require speed to re-established the functionality to the occupants as soon as possible.  A wet and dry vacuum is a great asset for a plumber this becomes an invaluable peace of equipment in circumstance like this.

Draining down a central heating system can have it problems.

The draining down of a central heating system is usually quite a straight forward procedure.  However, when draining down a dated or poorly maintained heating system this can have its problems.  The removal of system water can also carry sludge and debris from the header tank installed in the loft. Water travelling through narrow pipework and dirty radiators can be a potential cocktail for a blockage.  A blockage or air trapped in the system will drastically extended time spent on a repair. Complications such as this may require extensive measures in order to recover the systems previous level of performance.

What can be done to avoid central heating complication before draining down?

There are various methods that can be used in order to avoid complications before draining down. One being risk assessment and of the heating system in order to find the most appropriate method of draining down.  With the release of the system’s water there will be an influx of air drawn in,  this will need to be removed after refilling.  This trapped air is quite often the cause of problems such as airlocks that occur after a heating system as been refilled.

Airlocks can cause a boiler to overheat lockout a then restart resulting in luke warm radiators.  However, an airlock/vacuum can also be used by a plumber to slow down, restrain and prevent dirt from entering the central heating system.  This can be done with the use of purpose-made rubber bung placed strategically in the headed tank situated in the loft.

Has an alternative to this is a pipe freeze kit, Pipe freeze creates ice blockage within the pipe.  With the application of a spray canister containing special chemicals a zero temperature within a pipe can easily be achieved.  A freeze kit can for a little as £20 from most plumbers merchant.  Hiring a freezing machine is more costly however the time limitation experienced when using a spray canister will now be eliminated.  This allows a plumber to carry out work over a longer period of time without worrying about the ice melting.


One thought on “Water isolation before plumbing repairs

  1. Hi! Thanks a lot! Excellent article.

Leave a Reply

Your email address will not be published. Required fields are marked *