Boiler and Heating Care Schemes

(Please note – this article applies particularly to those with combi boilers.)


I would never attempt to persuade anyone to ditch a boiler insurance scheme which includes breakdowns. As I always point out, as a sole trader, I cannot be everywhere: I might be ill, away or just very busy when a particular customer’s boiler breaks down. At busy times no-one may be able to attend quickly. It’s perfectly understandable for people to want piece of mind and to know that they will be looked after promptly in the event of a boiler breakdown. In the end, the decision as to whether to take out a care scheme will be influenced by one’s attitude to risk.


Those with combi boilers who lack an alternative source of hot water such as an electric shower are most vulnerable to boiler breakdown. Those with stored hot water may benefit from an electric immersion heater which provides hot water on an emergency basis. (Unfortunately, and for reasons I can never fathom, an immersion heater is not always fitted to a hot water cylinder.) It is generally lack of hot water that is most damaging to morale – a few fan heaters and extra clothing can help cope with a lack of central heating.


All breakdown cover policies have a list of conditions – read them – if you have a contract get the documents out of the drawer and check – do it as soon as you’ve finished reading this! It is highly likely that there will be a clause stating that breakdowns due to sludge or blockages due to the heating system water are not covered.


Be warned – boiler breakdowns from this cause are not at all uncommon, particularly so for combi boilers. These generate hot water instantaneously as fresh mains water passes through one side of a device called a plate heat exchanger, on its journey to the taps or shower. On the other side is the heating system water circulating through the boiler. This device has particularly narrow water channels so is prone to blockage.


The symptom that this may be happening is that despite a good flow rate at the hot taps, the water runs hot for a while then goes cool. This is because not enough heat is being transferred from the boiler to the tap water, so the boiler stops burning for a while to protect itself from overheating. At the same time as the hot water is problematic, the central heating may be fine.


Your problem as a householder is that you have little control over the quality of your heating system water. About the only thing you can readily do is to keep air out by bleeding any radiators, particularly on upper floors, that are cooler at the top than expected.  Air, or more precisely oxygen, generates corrosion. (There are some excellent tutorial videos for this and a vast number of other home-related tasks on Youtube.)


How well the system was cleaned prior to boiler installation, how well it was dosed with good quality chemical corrosion inhibitor, and whether a system filter was installed along with the boiler, are likely to have been outside your control or sphere of interest. So if you find yourself being told your repair isn’t covered, you may well feel a little helpless and somewhat aggrieved.


It is possible to do tests on the heating system water and to check the adequacy of the inhibitor concentration for the premium brands using test kits – something you may wish to consider.


Nor does visual inspection of the water reveal that much – I recently replaced the plate heat exchanger in a boiler (correctly diagnosed by a colleague and not by me) which was badly blocked, where there was a system filter and the water drained from the boiler in order to do the job ran clear as spring water. The company providing the breakdown insurance adhered strictly to their terms and refused to cover the repair.


Problems on the fresh water side are less common, even in hard water areas, but scaling up does occur, and this too may well not be covered by the policy. Many installers fit in-line scale reducers of the magnetic or “electrolytic” type that just sit there forever. I don’t believe there’s any proper evidence they work – at least no-one seems to be able to present any, despite numerous theories as how they might work. I can believe in chemical ones that have a replaceable cartridge that needs to be changed annually, for the simple reason that as an engineer, I observe the TANSTAAFL effectnote1 to be real.


(I would like to record here a recent case of a plate heat exchanger blocked on the fresh water side by a faulty water softener (since replaced). Although they had every justification to decline to cover it, Worcester replaced the heat exchanger under warranty – it seems they value their customers’ loyalty.)


I’m not going to discuss any particular schemes but the following links provide useful advice:


My inclination would be:

  • Go for breakdown cover only and get the boiler serviced separately and annually by someone who does it properly (who could I be thinking of?).
  • Cover parts a well as labour so you don’t risk being ripped off for material.
  • Plan for a £200 repair every two years (£8.33 per month).
  • Set aside a sum for breakdowns not covered.






Note 1   TANSTAAFL – “There Ain’t No Such Thing As A Free Lunch”