Universal Heating Services Limited

Frequently Asked Questions

Fires and Fireplaces:

Q. What kind of gas fire will suit my home?

A. If you have a built-in chimney or flue, you should check if it is a ‘Class 1’ or ‘Class 2’ flue:

Class 1 Flues are typically traditional brick built chimneys – often found in houses originally built with coal fires (before 1970) and some newer houses.

Class 2 Flues come in two main types:

1. A flue Box/chamber connected to a 5” internal diameter pipe or flexible flue liner.
2. A ‘Pre-Cast’ flue – these are made from concrete pre-cast sections which are built into the inner leaf of the house wall and connect to a ‘Ridge Vent’ on the roof via a 5” pipe (in the loft space). These are found typically in houses built in the 1970’s and 1980’s and usually only take a very shallow inset gas fire.

If you have no flue, you have a choice of:

Balanced Flue gas fires – these are always behind glass and usually the flue goes straight out of the back of the fire through the outside wall (there are some which can have a longer flue). Balanced flue fires are ‘room sealed’ and draw their combustion air from outside the house, they are quite quiet in operation.

Power Flue gas fires are usually open fronted and have a fan to draw the flue gasses from the fire through the wall (the fan is fitted with a safety interlock to ensure that the fire can only be lit if the fan is working correctly). Rear and side flue versions are available – the side flue is in the form of a duct which runs along the wall at skirting board level. The open coal effect power-flue fires generally look more realistic than the balanced flue versions, but have the disadvantage that the fan makes some noise (this is a very subjective thing and people who are easily upset by extraneous noises should think twice before buying a fan flued fire).

Flueless gas fires are a relatively new idea and they use a catalytic converter to ‘clean’ the flue gasses, which are discharged into the room. There are strict specifications for the minimum size of room which can accommodate a flueless fire and they also need a dedicated wall vent to combat any potential condensation problems. Flueless fires are 100% efficient.

Q. What power of fire do I need for my room?

A. A rough guide to the heat requirements of a room can be calculated by measuring the volume of the room (length x width x height) in feet and multiply by 0.0015 – this gives the approximate heat requirement for a room in kilowatts:

Example: Room size 15’ x 12’ x 8’ = 1,440 cubic feet
x 0.0015 = 2.16 kW

Over-sizing a fire (particularly a gas fire) in a house may mean that you will hardy ever turn it on! A correctly sized fire is more effective in use and with the increasing use of central heating, the new generation of electric fires are becoming more popular.

Q. My gas fire coals (or pebbles) are sooty – is there something wrong?

A. Probably not! Most modern open-fronted gas fires burn with a slightly luminous flame (for good visual effect) – this contains unburned carbon particles, some of which are deposited as soot on the coals, pebbles, etc. A lot of this soot will burn off as the fire is used, but some may remain. You can clean the coals by brushing carefully with a soft paintbrush, or similar, and be careful to put the coals back in the correct positions – check the manufacturers instructions – as this can be very important on some fires! We can also supply special paint for gas coals, etc., to restore their appearance, BUT, DO NOT use normal paints – they may be flammable and hence very dangerous!
P.S. Don’t try to wash or scrub coals / pebbles – it will ruin them!

Q. I want a ‘Hole in the Wall’ Gas Fire – Do I need a Hearth?

A. The rules which required a hearth for all open-fronted gas fires have been relaxed, BUT, it is now up to the manufacturers to specify if a fire is suitable to be installed without a hearth. Many manufacturers recommend using a hearth to protect carpets and flooring from soot and other material falling out of the fire. If in doubt, as for advice, but consider any possible problems which may arise by not having a hearth!

Central Heating:

Q. What is a ‘Combi’ Boiler and which one should I buy?

A. A ‘combi’, or combination, boiler is so called because it is a combination of a central heating boiler and instantaneous water heater in one cabinet (usually it is possible to do away with separate cold water tanks and hot water cylinders, saving a lot of space).
Combis deliver the hot water at mains pressure, which is excellent for showers, but it is very important to ensure that you choose a boiler which will deliver enough hot water for your normal needs – the more powerful the boiler, the more water it can heat in a given time. Both Gas and Oil fired combination boilers are readily available and offer a range of features to suit many homes.

All combis are NOT the same - we would advise sticking with boilers made by well known British or European manufacturers that have good track record of reliability and spares / service backup in this country. We can advise you on suitable models for your needs.

Q. Can I still have an ordinary boiler?

A. Yes! It is still possible to have a conventional floor-standing, wall-mounted or back boiler fitted. Some installers may find it easier to fit combis and suggest – incorrectly – that other types of boiler can no longer be fitted. There is still a place for this type of boiler and they are likely to be available for some time to come.

Q. What is a ‘Condensing’ Boiler?

A. A ‘Condensing’ or ‘High Efficiency’ boiler is designed to extract about 15% more heat from the fuel burned that a ‘Standard Efficiency’ boiler – it does this by having a heat exchanger which cools the burned gasses to a much lower temperature, thus extracting more heat from them. A large part of the ‘products of combustion’, produced when fossil fuels such as gas and oil are burned, is made up of water vapour. In a standard boiler this is sent out in vapour form at a temperature well above boiling point, how- ever, a condensing boiler cools the gasses down well below boiling point and most of the water condenses out inside the boiler – hence the name. A special Condensate Drain is needed to remove this liquid from the boiler to a suitable drainage point.

New Building Regulations which come into force in 2005 mean that almost all new or replacement gas boilers will need to be ‘condensing’ types in order to satisfy the requirements for minimum boiler efficiency. Oil fired boilers will be subject to similar regulations - starting in spring 2007.

Showers:

Q. What sort of Shower will suit my System?

A. Electric showers will suit most systems where reasonable cold water pressure is available.

For the best performance with combi boilers, choose a good quality mixer shower – this should be either ‘fully thermostatic’ or ‘pressure compensating’ and designed for high pressure systems – you can’t use a pumped ‘power’ shower with a combi, but a good mixer shower should give you the same level of performance as a power shower without needing a pump. (The same comments apply to an ‘un-vented’ mains pressure hot water cylinder or a ‘multipoint’ instantaneous gas water heater.)

With Low Pressure systems (tank-fed) use either a simple gravity-fed mixer shower, or for improved performance, use a pumped power shower. It is vital that power showers are piped up exactly as per the manufactures instructions, or operational problems can easily arise. Power showers can be either self-contained (with the pump in the shower casing) or have separate pumps feeding a standard shower mixer.