Care & maintenance
Keep it running, and keep the scale out.
None of this is a sales pitch — it's what we end up telling people on the doorstep anyway. A heating system and the plumbing around it will look after you for decades if a few small things happen at the right time of year. Here's what we'd keep an eye on, season by season, in an ordinary Thames Valley house — plus the hard-water problem that quietly shortens the life of hot water kit round here. Anything involving gas is a job for a Gas Safe registered engineer; everything below is safely within reach of a careful householder.
Local knowledge
The local problem: hard water
Marlow and the towns around it sit on chalk, and the water is hard. It isn't dangerous and it doesn't taste bad — but it does leave scale, and scale is the single biggest cause of premature hot water failures we see.
01
Where it actually does damage
Scale forms wherever water is heated: on a combi's plate heat exchanger, on an immersion element, on a cylinder coil, in shower heads and tap aerators. The first symptom is usually a shower that has gone weak or a combi that takes longer and longer to run hot — not a dramatic failure.
02
The cheap fixes, in order
Descale shower heads and aerators a couple of times a year — a bag of descaler and an hour will often restore a shower people were about to replace. Keep stored hot water at around 60°C rather than higher: hotter is not better, it just scales faster. And keep the boiler's flow temperature sensible rather than maxed out.
03
When it's worth spending money
If you're replacing a boiler or a cylinder anyway, a scale reducer on the mains cold feed is cheap at that moment and awkward later. A full softener is a bigger decision — worth it in some houses, unnecessary in others — and we'll give you the honest view for yours rather than a quote by reflex.
Hot water
Unvented cylinders: the bits nobody checks
If you've got mains-pressure hot water, you've got an unvented cylinder — a Megaflo or similar. It's a pressure vessel, and it has safety kit that is supposed to be checked every year. A lot of them never are.
The expansion vessel
Either a separate vessel or an internal air bubble, it absorbs the expansion when the water heats. When it loses its charge the pressure relief starts dripping and you get water at the tundish. That drip is the warning, not the fault — it's worth acting on.
The tundish
The little open gap in the discharge pipe, usually near the cylinder. If you ever see water running through it, something has operated and should be investigated. Have a look at yours once a season; it takes ten seconds.
The relief valves and the PRV
The temperature and pressure relief valve and the pressure reducing valve on the cold feed both need exercising and checking annually — which is exactly what an unvented service is for. In hard water areas the PRV is a common quiet failure.
Season by season
Small habits that save an avoidable call-out.
Autumn
Get ahead of the heating season- Book the boiler service now rather than in December. It's the condition most manufacturers put on keeping a warranty valid, it catches small faults while they're still small, and diaries are a great deal emptier in September than in January.
- Run the heating for a full cycle on a mild day, before you need it. A pump that has sat still all summer, a seized zone valve or a thermostat that has quietly died are all much better problems to have in October.
- Bleed any radiator that's cold at the top and warm at the bottom — that's trapped air, and you're paying to heat a radiator that's half working. Check the boiler pressure afterwards and top it up to the mark on the gauge if bleeding has dropped it.
- Find where the condensate pipe from the boiler runs. If any of it is outside, in a cold garage or in the loft, it is the single most common cause of a lock-out on the first properly frosty morning — lagging it now takes ten minutes.
Winter
Keep it running through the cold- Know where your internal stopcock is and check it actually turns, before you need it at two in the morning. Under the kitchen sink is the usual place, and one that hasn't moved in twenty years often won't when it matters.
- Lag exposed pipework in lofts, garages and outbuildings, and leave the loft hatch ajar in a hard freeze so a little warmth reaches the pipes up there.
- Going away? Leave the heating ticking over on a frost setting rather than switching it off, and ask someone to look in. A burst pipe in an empty house is a different order of problem to a burst pipe in an occupied one.
- If the boiler locks out in freezing weather, a frozen condensate is the likeliest culprit. Thawing it gently with warm — not boiling — water poured over the outside run, then resetting, often fixes it. If it locks out again, stop and ring us.
Spring
See what the winter left behind- Have a proper look around the boiler, the cylinder, under the sinks and behind the bath for staining, drips or green corrosion on copper. Slow leaks do their damage quietly, over months.
- Cold spots at the bottom of radiators, or radiators heating in a strange order, usually mean sludge circulating in the system. Deal with it while it's still a cleaning job rather than a pump-and-heat-exchanger job.
- Check the boiler pressure gauge while the system is cold. If you're topping it up more than once or twice a year you have a leak somewhere — in the system, the expansion vessel or through the pressure relief — and it's worth finding.
- Spring is the sensible time for the bigger work: a new boiler, a cylinder, a bathroom, a heat pump survey. No rush, no cold house while it happens, and more room in everyone's diary.
Summer
Do the disruptive jobs while it's warm- Run the heating for fifteen minutes once a month even in summer. It keeps the pump and zone valves from seizing, which is exactly what they do if left still from May to October.
- Open every thermostatic radiator valve fully for the summer. Left closed, the pins under the heads stick down — and you find out in the first cold week, when half the radiators stay cold.
- Descale shower heads and tap aerators. In this part of the Thames Valley the water is hard, and a poor shower is very often a scaled head rather than a pressure problem.
- If a bathroom, a cylinder or a heat pump is on the list for this year, get it looked at before the tiles and units are chosen. It's the cheapest possible moment to find out that the shower you like needs more pressure than the house has.
Three things not to have a go at yourself
- Anything involving gas. It is illegal for anyone who isn't Gas Safe registered to work on a gas appliance, boiler or flue — including "just having a look". If you smell gas, turn the supply off at the meter, open the windows, don't touch switches, and ring the National Gas Emergency Service on 0800 111 999.
- Taking the case off a boiler. Everything a householder should need — pressure gauge, filling loop, reset button, timer — is on the outside. Behind the case there are live components and a sealed combustion chamber that only a registered engineer should be opening.
- Unvented cylinder safety kit. The expansion vessel, the temperature and pressure relief and the discharge arrangement on a Megaflo-type cylinder are pressure-system components — checking or altering them is a job for someone qualified on unvented hot water, not a spanner and a video.