We are only able to answer questions of a general nature relating to products of our manufacture.

We are unable to answer questions relating to specific installations as these would by nature normally require a visual survey by a professional plumber or installer. For professional or technical advice on specific installations we would suggest you visit The Institute of Plumbing web site.

www.iphe.org.uk/indemnity.html

There follows various frequently asked questions and answers that are listed under the following subject categories:

• Traps
• Pipes and Fittings
• Condensate Products
• Floor Gullies
• Air Admittance Valves
• WC Connectors

Traps

1) What diameter and depth of seal should my traps have?

Building Regulations state that appliances that are connected to a soil pipe should comply with the following table.

* The depth of seal may be reduced to 50mm if basin is fitted with spray taps and a flush grated waste without a plug.

** Where these appliances discharge directly to a gully the depth of seal may be reduced to not less than 38mm.

2) Why does McAlpine Manufacture traps with 19mm water seal and where can they be used?

Current building regulations state the minimum depth seal for traps should not be less than 38mm. However, 19mm water seal traps have been manufactured to meet the demand for replacement traps where the original shallow seal traps were installed prior to the current regulations.

It is not uncommon in older properties for the waste from baths or showers to have shallow seal traps and discharge into an open hopper head. New 19mm water seal traps are often used when replacing the sanitaryware in these properties. This practice does not comply with current building regulations and they could be rejected if the installation comes under the scrutiny of the local authority building control officer.

3) What are the flow rates for McAlpine's Top Access Shower Traps?

Flow rates vary depending on the type of waste outlet and the head of water over the waste. The configuration of the discharge pipe work will also have some effect. However, when tested under controlled conditions with a 15mm head of water over the waste outlet our 50mm water seal top access shower traps have a flow rate of approx 26 litres per minute.

4) Why do I get dirty water from the sink in my washing machine?

Check that hose discharge from washing Machine loops up above the minimum height as specified by the machine manufacturer and at least to the underside of the work top for an inset sink before connecting into the sink trap.

See installation details for washing machine traps

5) Why will the inlet nut of a trap not tighten on to my waste outlet?

The chances are that your waste outlet is of continental manufacture and not compatible to BS Trap inlet nut. Use T12A-F fitting on 1½ inch or S12A-F fitting on 1¼ inch 32mm waste outlets to convert connection back to a compatible thread.

6) I have installed a new shower and used a McAlpine top access shower trap. There is a smell coming from my shower waste, what is wrong with the trap?

Drain smells can enter a dwelling via the waste and trap if the water seal within the trap has been lost due to excessive positive or negative pressure within the soil and waste system or due to evaporation. Check to ensure this is not happening and that a trap with a minimum 50mm water seal has been installed. If smell still persist check to ensure the ‘O’ ring on the dip tube has not been damaged, and that the dip tube is correctly positioned within the trap?

7) Why does water not run away in my shower?

If it is not due to the obvious reason of a blockage caused by a build up of debris, the problem could be due to backpressure within the discharge pipe. This can be because at some point the discharge pipe has retained water, which is preventing air from flowing freely through the pipe. Plumber should check out the installation.

8) What is the difference between an anti-syphon trap and a re-sealing trap?

A re-sealing is designed to allow air to pass through the water seal under negative pressure but will retain sufficient water to ensure the minimum depth of seal is retained. Whereas an anti siphon trap has a small mechanical valve, which opens under negative pressure. Both versions will break the syphonic action thus protecting the water seal. Note. the re-sealing trap may be noisy.

For more details see relevant pages on web site or catalogue

9) When should I use an anti-syphon or re-sealing trap?

Generally when the waste pipe or discharge pipe from an appliance is beyond the limitations of an un-vented waste pipe. Usually more critical on basin and bidet wastes.

See tables in installation details

Pipes and Fittings

1) What is the diameter of McAlpine's pipes?

McAlpine HDPE pipe is manufactured to the imperial dimensions as follows:

2) Why does my pipe not fit into Multifit fittings?

Multifit fittings should accept most plastic and copper waste pipes manufactured to suit the UK market. Check that the pipe meets the minimum requirement of either 32mm or 38mm or 51mm internal bore. It may be helpful to chamfer the inside of the pipe to remove any burr.

Continental size pipes can be connected using our:

• DIN to UK Straight couplings: S28L-ISO, T28L-ISO, Z28L-ISO, or

• DIN to UK Bends: MS4-ISO, MT4-ISO, MZ4-ISO.

3) How do I fit two machine hoses into a single 40mm stand pipe?

Use V33WM fitting.

See washing machine traps and fittings details

4) Are McAlpine's pipes and fittings suitable for boiling water?

Yes, providing the discharge is a gravity discharge and not pumped or pressurised.

Condensate Products

1) Can I connect my condense drain from my boiler to a rain water pipe?

It depends on where the rain water pipe is discharging. Condense is acidic and should only be discharged via plastic pipe into a foul drain. Where this is not possible it may be discharged into a special soakaway that contains lime chippings to neutralise the acidity.

2) Where should soakaway be installed?

Soakaways should only be used in free draining porous soil and should be at least 500mm away from any footings or structural walls it should also not be in the vicinity of other services such as gas, electricity or water connections.

3) How often should I replace lime chippings in my soakaway?

Lime chippings will slowly dissolve depending on the amount and acidity of the condensate passing through the soakaway. Check the level and top up if necessary when carrying out an annual boiler service.

For more information see installation details

Floor Gullies

1) What is the difference between TSG Gullies and MD100 Gullies?

All TSG Gullies have a flange and clamp ring, which allows a waterproof joint to be made between the gully body and the floor covering or waterproofing membrane ensuring that no water can penetrate through the structure of the floor.

2) Why does water not drain away until I lift the cover plate and dip tube?

This is indicative of a problem of back pressure. This is normally found to be due to a section of pipe between the gully and the soil vent pipe retaining water, which is preventing the free flow of air through the discharge pipe. Plumber should check out the installation.

3) What diameter pipe should be used for discharge of Trapped shower Gullies?

See dimensional drawings and installation instructions.

4) Can the top of Gullies be changed?

See catalogue for conversion kits.

Air Admittance Valves

1) Why does my toilet not flush properly when valve is fitted but flushes okay when valve removed?

The problem is due to back pressure and would indicate that there is a blockage or section of pipe that is full of water between the WC and the vented section of drain preventing the free flow of air through the pipe. As there is nowhere for the air to go the water will not flow.

Valves are designed to allow air into the pipe work under negative pressure but will not allow air to come out under a positive pressure.

2) Can I fit an air admittance valve outside?

Ventapipe valves are designed for and only allowed for installation internally.

3) Can I fit my air admittance valve horizontally?

Ventapipe valves should only be installed vertically.

See installation guide for more details of Ventapipe Air Admittance Valves

WC Connectors

1) Are McAlpine's Flexible connectors covered by a British Standard (BS)?

There is no British Standard for flexible WC Connectors.

However, McAlpine flexible WC Connectors are independently certified as conforming to DIN 1389-02. BSI have confirmed that the technical content of this standard would be identical to that of a BS EN.

2) Can the Building Control Officer refuse to accept Flexible WC Connectors?

They can refuse any products that were not included or detailed on the original building control approval documents.

3) Will your Flexible connectors block due to corrugations on the inside?

The material has been stringently tested and found not to retain sedimentation of organic products or chemical substances on the inside wall of the pipe.

Since their introduction the incidence of blockages have been no more than installations using conventional materials.