A system boiler works on the principle of stored hot water. It provides heat for your heating system while being able to heat a hot water cylinder (like 
a Megaflo). This guarantees simultaneous supply of hot water to all outlets. These type of boilers work with both vented and unvented how water cylinders.

System boilers operate on a sealed system like the combination boiler. As the system is not affected by mains water pressure, they can operate in areas where combi boilers cannot (like lofts). System boilers are usually compact as all the major components like the pump and the diverter valve are built into the boiler.

A system boiler is a great choice for a larger home or family with hot water needs that can’t be met by a combi boiler. You will need a tank in the airing cupboard, though.
 

We can supply and install any type of boilers. We will assess your individual needs and advise on a suitable boiler. There are several very good central heating boiler manufacturers in the market. We usually recommend A-rated Worcester boilers for their efficiency and size but we have also found Ideal, Glowworm, Baxi and Valiant boilers to be equally good in terms of performance and reliability.
 

Gravity fed systems are the most common type of water system in the UK. The mains water enters the property and flows through a stopcock (usually found under the kitchen sink) before dividing into two pipes. One of the pipes takes water at mains pressure (high pressure) to the cold tap in the kitchen sink. The other pipe runs up into the roof space and fills a large water tank, which feeds the cold taps in the bathroom and the toilet cistern. Water also runs from the tank through a pipe to a hot water cylinder which provides hot water to the bathroom and kitchen sink.

The system is called gravity fed because it is only the weight of water falling from the tank which makes it flow through the pipes. The water is at a much lower pressure than the mains water (at the kitchen sink) and so a gravity fed system is also called a low pressure system. That’s why it is usually recommended to have a shower pump to increase the flow rate.

Gas Safe Register™ is the official Great Britain and Isle of Man registration scheme for installers and maintenance engineers dealing with natural gas appliances, which replaces the previous system run by CORGI until 1st April 2009. By law, anyone carrying out work on gas installations and appliances in your home must be on the Gas Safe Register™. Watermarcs is a registered Gas Safe Register™ installer.

An unvented hot water system is a cylinder where hot water is stored at mains pressure and therefore hot water flow rates are much better than traditional open vented systems. Megaflo is a market leading name for unvented cylinders and is manufactured by Heatrae Sadia.

If you have a cold water storage cistern in the loft and a hot water cylinder in an airing cupboard, then you have a typical gravity fed system in your property. Your water pressure is determined by the height of your cold water storage cistern in relation to the appliance outlet. For example, a weak shower could be due to low water pressure, but in an ideal world this could be solved by raising the height of the storage cistern. However, this isn’t always possible and pumps can be used to boost the pressure.

Thermostatic radiator valves control the temperature of an individual room or area. They are fitted to your radiators and have an internal thermostat to enable temperature control to individual rooms in your home.

This usually means there is air trapped at the top of your radiator and it is stopping any more hot water filling the radiator. To resolve this problem you can bleed the radiator to release the air by opening the bleed nipple (a small square peg at the top of the radiator, usually protected by a round cast in the radiator body) and allowing the air to hiss out. Hold a cloth close to the bleed nipple and when water starts to come out the air should have gone. If this does not help or the problem reoccurs we suggest that you have your central heating checked by a heating engineer in case there are any underlying system problems.

Assuming the radiator has reached operating temperature, this usually means there is a build up of sludge and rust at the bottom of your radiator and this displaces any water leaving the bottom of the radiator cold. In this case we advise that you have your heating system power flushed.

This usually means that the feed and expansion tank in your loft has run dry which can indicate a problem with the ball valve. This needs addressing quickly and can be resolved by replacing the ball valve.

This could indicate a faulty central heating pump which should be checked by a heating engineer.

An immersion heater is an electric element which screws into the hot water tank. It is wired to the mains electrical supply via an isolating switch, a thermostat to control the temperature, and sometimes a timer which enables you set the times you wish to have the water heated. Using a timer, together with a well insulated tank, it is possible to heat the water during the night, when electricity rates are cheaper, and use it during the day.

Power flushing is the most efficient and effective method of cleansing a central heating system. The principle is to circulate a cleansing chemical and water mixture under controlled conditions to remove debris from the system. The chemical cleaning water has a high flow rate but not much pressure, so your existing pipework remains quite safe. By connecting the power flushing pump to the heating circuit in place of the central heating system pump, boiler or radiator the circuit can be thoroughly cleansed of limescale and corrosion debris.

What symptoms indicate that Power Flushing would be beneficial?

  Radiator water black with iron oxide sludge
  Heating system slow to warm up
  Cold spots in the middle of radiators
  Unpleasant boiler noises
  Repeated pump failure
  Radiators need frequent bleeding
  Leaking radiators from pin holing in the radiator body

Power flushing will clean a central heating system internally improving radiator performance and heat output.

The power flushing pump is simply connected into the heating system, either across the standard circulator pump couplings, across the tails of one radiator, or wherever most practicable.

Power flushing is a highly effective cleansing operation which works by pumping water at a much higher velocity than usual through the heating system, to loosen and mobilise harmful corrosion deposits, and to suspend them in rapidly moving water. The process is made more effective by specialist cleansing chemicals, and an instantaneous flow reversal device, which creates turbulence in the radiators to optimise the ‘pick up’ of the debris.

Once loosened, the unwanted debris is purged from the system with clean water. At the end of the flushing process, the system contains fresh clean water, and reinstatement of the system to normal operation takes only a few minutes.
During the process, radiators are individually flushed, without removing or disconnecting them from the system, by directing the full output of the pump through each radiator separately.

Power flushing is not a high pressure operation, and it is suitable for most domestic wet central heating systems. It is carried out with minimal disturbance and disruption to the normal operation of the system, often without disconnecting the boiler or any radiators.

  Cures flow and Restores system efficiency
  Restores heat output to radiators
  Cleans the whole system, including underfloor pipework
  Removes aggressive water; treatment prevents further corrosion
  Cures or prevents boiler noise
  Power flushing and descaling in only one visit
  Complete process carried out in less than one day
  More effective than traditional flushing methods
  Minimises boiler warranty problems

The high efficiency and compactness of the heat exchangers on modern condensing boilers (developed to minimise fuel costs and pollution) makes them more susceptible to problems caused by debris in the system water. Boiler manufacturers insist that heating systems must be thoroughly flushed before installing a new boiler.

It is important when installing new boilers into old systems that all sludge is first removed from the system or this could accumulate in the new boiler and lead to premature failure. Additionally, in hard water areas existing systems will have accumulated limescale together with corrosion deposits in the heat exchanger, which could easily have reduced the boiler efficiency by over 5%.

All new systems should be pre-commission cleansed in accordance with BS:7593 and Benchmark. This ensures flux residues, excess jointing compounds, mineral oil and other contaminants that can be found in the system following installation, and that can effect the performance of the system or cause component failure, are removed.

Yes it can, but the flow rates will be greatly reduced and so the flush may not achieve the same results as with a ‘normal’ larger bore system. A microbore system is a heating system that uses pipework smaller than 15mm. In the UK this is normally 8mm or 10mm. Microbore systems are more prone to circulation problems and blockages.

The success of a power flush will depend on the level of heating system corrosion which has occurred beforehand. The process will cure most circulation problems, but cannot undo the corrosion and gradual decay that has led to the need to power flush the system.

Whilst it is rare for a heating system to experience leaks after the power flushing process, it is not possible to inspect a system internally beforehand, and the need to use a flushing and dispersing chemical for effective cleansing means that occasionally we may find a leak.

The advance stage of corrosion required for such a situation means that the leak would occur imminently even without a power flush. We believe that it is better that it occurs whilst we are present to remedy the problem, rather than for it to arise over a weekend or whilst the house is unoccupied.

Systems which have been neglected over a period of time, or have not been treated with an effective corrosion inhibitor, may have severely compacted corrosion debris in the pipework, radiators, or boiler, and it is possible that even after the power flush, some radiators may still not be fully effective, or boilers on the margin of failure may cease working due to sludge and debris later breaking loose and collecting in the heat exchanger.

Virtually all older central heating systems are suitable for power flushing. If you are having a new boiler installed you will have to have the system power flushed.