Hot Water Cylinders
Here at GHS we are skilled in the service, repair and replacement off all types off hot water tanks and cylinders.
There are basically two hot water cylinder systems, Vented and Unvented. These are found in most homes and business premises. Modern buildings tend to have unvented and older-style buildings have Vented. The older style tends to be copper tanks.
Unvented Hot Water Cylinders
The unvented cylinder is a relatively newcomer to the market place. They only became legal to install in 1986. Due to there performance they have very quickly become the hot water cylinder of choice by many.
These cylinders are directly fed by mains pressure cold water. There is no need for a cold water tank and their flow rates are as good as the main pressure. Your kitchen tap should be mains cold water feed which would give you an idea of the flow rates in your home. As you are not relying on a gravity fed system, you can install them just about anywhere. You can even get cylinders that lay horizontal. They area also a lot quieter than a normal tank as they fill directly, rather than by a slower gravity system. The big advantage is the fact they are a sealed system. This means your hot water can never get contaminated. The only real down side is they require safety devices to release the pressure in the event of overheating. This is an expansion vessel (a round steel ball or oblong vessel) and a pressure relief valve. These make them very safe as both will never fail at once. If one of them does you generally lose or have hot water issues.
The downside is if you lose water pressure you lose your hot water.
Unvented cylinders can only be installed by a qualified engineer.
Vented Hot Water Cylinders
These are found in older houses with what used to be called a “traditional heating system”. They are copper tanks with either an old lagging jacket, or newer ones are manufactured with a made to measure foam jacket. They are fed from a cold water tank usually in the loft. Their safety system for when the water expands is quite simple, it just returns up the vent pipe back into the header tank. These are gravity systems so the hot water pressure is controlled by the distance between the tank and the inlet of the cylinder. They are a lot smaller in size and a lot easier to install. This makes them cheaper to buy and fit.
A lot of flats tended to have Combination Tanks (combi tanks). This is simply a traditional hot water cylinder with a built-in header tank, that replaces your cold-water tank in the loft.
With the water pressure issue some houses end up installing shower pumps for the hot water to bathrooms on the first floors.
Direct and Indirect Cylinders
Both Vented and Unvented come in either Direct and Indirect heating options.
Direct systems mean the water is heater directly from an element or immersion heater. This is generally the most expensive way to heat water (essentially it’s a big kettle). These are common on estates with no Gas or Oil. They were very popular when Economy 7 gave you cheaper electricity at night. Economy 7 cylinders have two elements, one for day use and the other for night use. They don’t work at the same time.
Indirect Cylinders are heated by an external heat source via a copper coil inside the cylinder acting as a heat exchanger. The heat source is usually either a gas boiler, oil boiler, air source heat pump or solar panels on your roof. You can if you want to have two or three coils in a tank so you can have a blend or systems heating your water.
The great thing about Indirect systems is that you can still have elements installed, which means if your boiler breaks down you still have hot water. If you have more than one bathroom or shower you should look to install an Unvented Indirect system with back up elements.
If your looking to install a new hot water system we would be happy to help.
Click on our contact form below and we can arrange a quote or just call us if you have any questions.
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