What is a cold feed and expansion pipe?

A feed and expansion pipe (often referred to as the cold feed pipe) is the pipe connecting the hydronic heating system tank to your boiler. Water is fed through this pipe on commissioning to fill the system and also to permit water when heated up to expand to the hydronic heating system tank above.

What is the purpose of cold feed pipe?

Cold Water Feed Pipe This pipe supplies cold water to the hot water cylinder for re-heating and eventual use. It is prudent to fit an isolating valve on this pipe whenever possible.

What does a feed and expansion tank do?

The feed and expansion tank, header tank, or feed and expansion cistern as it is technically known, is a cistern which supplies the central heating circuit with water and accommodates the expansion of the water when it is heated by the boiler. It is typically made out of plastic.

What is the main purpose of the feed and expansion cistern?

The feed and expansion cistern is used on all open vented central heating systems – pumped heating and gravity hot water systems and fully pumped. Whilst the cistern allows the system to be filled up, its main purpose is to allow water in the system to expand.

How do you unblock a cold pipe?

Easy way to check/ unblock cold feed is to close pump valves (this is assuming the feed and vent are close coupled on the flow before the pump) remove the pump and get a bowl and a bucket. With pump removed put bowl under top pump valve and open valve. Water should gush out into bowl.

What is WRAS and why is it important to comply with it?

The role of WRAS is to assist the protection of public health by preventing contamination of public water supplies, whilst also fostering the efficient use of water by promoting and facilitating compliance with the Water Supply Regulations*.

Why does cold feed go through expansion pipe?

This is due to the weight in the water of the central heating tank versus the weight of the water in the expansion pipe. Because the weight is much lighter in the expansion pipe, the water then expands through the expansion rather than the cold feed.

What is the purpose of an expansion pipe?

The expansion pipe or vent pipe is a pipe associated with a cold water storage cistern or a feed and expansion cistern. Its purpose is to accommodate the expansion of water when it is heated, and to allow any excess water to vent harmlessly into the cistern.

What is the purpose of cold springing of pipes?

Cold Springing of Pipes. Cold spring is the process of offsetting (or pre-loading) the piping system with displacement loads (usually accomplished by cutting short or long the pipe runs between two anchors) for the purpose of reducing the absolute expansion load on the system.

Why does a central heating system need a feed and expansion tank?

Such installations are as inadequate as they are dangerous. The ball valve in a feed and expansion cistern is set so that when the central heating system is cool, the water level is only slightly higher than the outlet at the base of the cistern. This is so that the water in the central heating system has the space to expand when heated.

What’s the difference between backflow and combined feed and expansion?

“backflow” means flow upstream, that is in a direction contrary to the intended normal direction of flow, within or from a water fitting; “combined feed and expansion cistern” means a cistern for supplying cold water to a hot water system without a separate expansion cistern;

What does expansion mean in a water heating system?

“expansion cistern” or “expansion vessel” means a cistern or vessel connected to a water heating system which accommodates the increase in volume of water in the system when the water is heated from cold; “expansion valve” means a pressure-activated valve designed to release expansion water from an unvented water heating system;