Plumbing for Washing Machines and Dishwashers

Washing machines

These may require both hot and cold supply, though some work on a single hot or cold supply. The principles of connection are similar for most makes.

Connection to water supply is provided by flexible pipes which fit to the back of the machine. These are usually longer than needed for permanent connection, since a washing machine can be connected for temporary supply to the taps.

These pipes can be easily cut with a sharp knife, though take care to cut squarely and allow sufficient flexibility for the unit to be pulled out for access. The pipes are connected with hose clips and unions to the supply.

Hot water can be supplied by an independent source or by a back boiler. This can be from either a gas or an electric storage system, including an immersion heater, or a multi-outlet instantaneous gas heater, provided this has sufficient hot-water pressure. Single-outlet heaters of any type should not be used.

A minimum head of 2.44m (.28 bar) is generally needed for both hot and cold supply.

Connections can be made from existing pipework by extensions or branches, joined by ‘tee’ connections. You should incorporate a shut-down valve in the pipework, so that supply can be cut off for ease of removal of the machine.

All fixed pipework must be clipped to wall surfaces and can usually be run unobtrusively at the rear of kitchen units. Once pipe stems are prepared, the flexible hoses can be pushed over the pipes and the hose clips tightened up.

Smear soap over the pipe-connecting ‘tails’; this enables pipes to be pushed well home to ensure a leak-proof union.

It may be necessary, to avoid water siphoning, to incorporate, into the permanent waste pipe, an airbreak or vent to the atmosphere. This should be at least 455mm above the level on which the machine stands.

To achieve this, use a ‘stand’ pipe with a minimum diameter of 35mm, into the top of which the crooked end of the drain hose of the machine is fitted. This should be mounted so that the top end is 790mm above the level of the floor.

The gap between the rubber crooked hose and the bore of the standpipe provides the necessary airbreak to avoid siphonage. The lower end of the standpipe should be taken to the drain, maintaining a gentle, even fall.

Fix the plastic stand and drainage pipe to the wall with plastic clips. A hole through the house wall can be cut with a bolster and cold chisel, or by using a hired rotary hammer drill with a plug-cutting attachment.

On the outside wall, the waste pipe should be fitted at a slight slope to the drain and fixed at intervals with clips to the wall. Pipework can be of the plastic, solvent-weld type or push-fit connectors.

Electrical supply can be from 13A ring main or use a separate point of the same rating, with a three-pin plug. Once the unit is connected at all points, open the shut-down valves to supply water to the machine.

Machines can be located beneath working surfaces; in the case of top-loading units, these should have sufficient pipework to pull the machine forward to an accessible loading position.

Dish washers

The supply arrangement for a dish washer and installation are similar to those of a washing machine. It can usually be operated as a permanently plumbed-in unit or temporarily connected.

The most convenient position in the kitchen should be chosen, since it is in daily use. This is probably under a working top, between kitchen units, on a working top or fixed to the wall. Non-standard-height units can be mounted on a simple timber plinth to bring them up to the height of other appliances.

Connections for a dish washer usually consist of a 15mm hot supply and a 22mm drainage outlet. Usually, connection can be made to the kitchen hot-water supply with a ‘tee’ branch end, fitted with a stopcock or gate valve, to shut down supply if the unit has to be removed. Connections are made using a hose ferrule fitted on to a branch pipe stem.

The outlet pipe should incorporate a water-seal dip. This can be made by bending the pipe with a spring or bending machine. The pipe slides into the drain hose and fixes with a hose clip.

The drain-pipe connector should be at a maximum height in the highest part of the drain line, but no higher than 900mm.

The 22mm pipe, which can be of copper, stainless steel or plastic, should be taken out through the wall. It must be clipped to the outside wall, drain into the trapped yard gulley, and maintain a gentle fall.

Like washing machines, dish washers should be provided with separate power point or connected to a standard 13A ring main with a three-pin plug.

10. November 2011 by admin
Categories: Featured, Handyman Tips | Tags: , , , , , , , , , | Comments Off on Plumbing for Washing Machines and Dishwashers


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