Peter Wells Plumbing

Plumbing & Heating Engineer

Setting central heating programmers

When a property is fitted with a properly insulated cylinder i.e. Polyurethane lagging often known as herculag, then the water stored is kept at the correct temperature through a 24hr period such that it will only lose the equivalent of 1.5 Kw of heat during that time period. Therefore it is better for 2 reasons to set the programmer for hot water on constant; this will allow the hot water to be maintained at a temperature of approximately 60 degrees C. At this temperature Legionaries disease cannot flourish.

If the system cannot be programmed for independent times for hot water and heating then when there is a demand for heating, the boiler is not trying to heat the water at the same time as the heating, in the winter that means the radiators will heat up quicker and the property will feel warmer quicker.

It has also been found that when the heating is turned down at night say 15 degrees C and then turned up in the morning the boiler uses less gas because the fabric of the property does not cool down and this allows the property to achieve a level of comfort much faster, that is why programmable room thermostats were introduced, they would allow the owner to programme what times the heating was turned up and then which times it was turned down. Some also have a holiday button for telling it how many days you will be away then it switches back up the day you come home.

There are also programmers that will allow you to communicate with them with your cell phone.

Open vented heating systems

If you have an open vented heating system, (one large and one small storage tank in the loft space usually) then you will have a hot water cylinder and there will be either one or two motorised valves controlling the temperature of the heating and probably the hot water as well; the exception to controlling hot water temperature is when you have an old style back boiler which are usually installed with gravity flow to the hot water cylinder and pumped flow to the heating, although there are still properties with gravity flow to the radiators as well.

When the system is fully pumped there are either two of 2 port valves or one 3 port valve. With a 2 port valve system there must be a bypass tube so that in the event that both valves fail at the same time or one after the other, the bypass tube allows water to circulate back to the boiler and the boiler then switches off. It is important to realise that the bypass should be fitted with an automatic bypass valve, not a gate valve, the automatic bypass valve will only open to let water flow when the resistance in the bypass loop reaches a critical preset point, the advantage of this is it allows all the radiators in the system to be balanced and work properly, which is not possible with a gate valve used on the bypass loop.

If with this system described above with a 3 port valve it is noticed that the heating stops working, it is often because the motor in the valve has stopped working and needs replacing. To prove it is the motor that is faulty if the head of the valve is a metal casing then on one side of the valve there is a thin metal lever which can be manually moved against the pressure of a spring, if the lever is slid over and lifted at the same time, when released it will stay open, caught against a notch in the case, this will open the valve and allow the heating to carry on working until a replacement is available, BUT the temperature of the hot water can now no longer be controlled so the hot water will get too hot and it will be necessary to lower the thermostat on the boiler temperature to avoid get scolded by hot water.

Sample plumbing work undertaken:

This plumbing is going behind a combination boiler that had all the pipes going upstairs and none showing in the kitchen that is why the route had to be done like that. The Gas pipe, and the central heating flow and return were all done in 22mm pipe the cold feed supply and hot water out were done in 15 mm pipe as they were mains pressure. The boiler manufacture did not leave much space for fitting all the pipes behind the boiler.

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