Please Note: This Article is 6 years old. This increases the likelihood that some or all of it's content is now outdated.

Water central heating systems are always a worry for landlords at this time of year because frost damage can easily cause busts and flooding in your rental properties. If your property is a flat within a block, a burst here can be disastrous as it will flood any flats below.

Many tenants, especially young tenants are unaware of the importance of keeping a low level of heat in the property at all times, especially if they go away on holiday. It’s a good idea to remind them about this by sending your tenants a Winter Weather letter (see:

Letting agreements should all have a clause about leaving the property vacant for more than 2 weeks, and keeping a minimum temperature when the property is vacant, as all landlord insurance policies have a restriction on the length of time the property is left vacant. This means that landlords / agents need to keep an eye on their properties and inform the insurer if it is vacant for any length of time.

In addition to burst pipes, gas boilers often fail as winter comes along as they are being asked to do a lot more work following a long summer break. So unless you are prepared for a call from your tenant as you are sitting down to Christmas dinner, make sure you’ve had those boilers serviced, and remember, all gas systems, boilers, fires and appliances need an annual Gas Inspection and a Gas Safety Certificate, a copy of which you supply to your tenant.

Water Central Heating Systems:

A water central heating system consists of basically the boiler, the radiators and the interconnecting piping. The boiler heats the water and (normally) a pump circulates the water through the pipework and radiators and back to the boiler. There are a number of different arrangements of boiler, pipework and supply to the radiators, with each system having its own advantages and disadvantages.

There are 3 basic arrangements for the pipework connecting the boiler to the radiators:

  • Single pipe loop
  • Feed and return pipes
  • Micro bore

General practice is for the pipework (copper or plastic) to be installed below the radiator. With suspended timber floors, this is no great problem as the pipes can be installed below the floorboards with the risers to each radiator passing through holes in the floorboards. The pipework is normally either run between the joists or across the joists through cut-outs cut in the top of the joists. Except for microbore, the pipework should be supported below the floor boards to avoid excessive weight having to be supported by the pipework itself. One common problem here is that careless fitters cut too deep into the joists and therefore weakening them. There pipes also need to be insulated if they are in a ventilated crawl space.

This method of installation is impractical where the building uses solid floors. Such installations normally have high level feed pipes with fall pipes feeding single or adjacent radiators. Where the ceiling of the room is suspended, the pipework is normally installed between the joists of the ceiling from above, but this may not be possible where each floor is a separate dwelling.

A third alternative is to run the feed pipes around the top of the wall just below the ceiling with fall pipes. It is never really desirable to run the feed pipes at floor level because problems arise where the pipes have to cross doorways. An alternative is to chase out channels in the floor and bury pipes, which is much better than having unsightly exposed pipes.

Where high level feed pipes need to be installed in a loft, the pipework must in insulated. It is not normally considered necessary to insulate pipework below insulated suspended floors or ceilings.

For efficient operation radiators need bleeding from time to time and the pressure in the system brought back to optimal at the boiler.

Heading Off Trouble Freezing Pipes

When water freezes, it will expand. That’s why a can of coke will explode if it’s put into a freezer to chill quickly and forgotten. When water freezes in a pipe, it expands in the same way. If it expands enough, the pipe will burst, a copper pipe splits and water escapes. If there’s no one present and water flows for extended periods, serious damage will result.

Pipes in attics, crawl spaces and outside walls are all vulnerable to freezing, especially if there are vents, cracks or openings that allow cold, outside air to flow across the pipes. Wind chill, the cooling effect of air and wind can play a major role in accelerating freezing and bursting water pipes.

Even small holes in an outside wall can provide enough access for cold air to reach and freeze pipes. The size of pipes and their composition (e.g., copper or PVC plastic) may have a bearing on freezing and bursting but these are minor factors compared with the absence of heat, pipe insulation and exposure to a flow of below freezing cold air.

Precautions against winter bursts

Remind your tenants about leaving the property vacant for longer than two weeks and that they must inform you if they do.

Remind them that a low level of heating is required at all times in cold weather.

If you have a vacant property and you are not prepared to keep it heated you need to fully drain down the system.

Two useful Guides:

Big Boiler Handbook – All you need to know about boiler care to give you peace of mind

Association of Plumbing & Heating Contractors APHC Guide to Hot Water Systems in the home

Please Note: This Article is 6 years old. This increases the likelihood that some or all of it's content is now outdated.


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