Empty Cupboard, Clear Answers: The Bits Left Behind After a Glow-worm Combi Conversion

A Glow-worm combi swap has a funny way of making a house feel different. The new boiler goes on the wall, the hot water arrives at mains pressure, and then you open the airing cupboard and find a gap where a cylinder used to be. Up in the loft, there may be a tank-shaped hole in the insulation and a few pipes pointing at nothing much.

That aftermath is not a sign that something has gone wrong. It is simply the physical side of moving from a tank-fed hot water system to a combi. But it is worth understanding what should be removed, what might stay, and what “making good” actually means — because those details belong in the quote conversation, not in a surprised phone call afterwards.

The cylinder and immersion heater: out, but not always instantly

With a traditional vented system, the hot water cylinder is the centrepiece of the airing cupboard. A Glow-worm combi doesn’t need it. It heats water on demand, so the cylinder becomes redundant.

In most straightforward conversions, the installer will drain the cylinder, disconnect it, and remove it. The immersion heater usually goes with it — either still fitted in the cylinder or taken out separately. If the cylinder is being scrapped, the immersion is generally part of that package. It is not normally left behind as a spare, partly because old immersions are not a universal fit for anything you are likely to install later.

There are exceptions. Sometimes access is awkward, the cylinder is boxed in, or the homeowner wants to keep it for a shed or outbuilding. That is a conversation to have before work starts. If removal is not included, get that in writing. “Old cylinder left in place” is a very different quote from “old cylinder removed and disposed of”.

One practical point: the cylinder is heavy, and an empty one is still bulky. Removal may involve more than a quick lift, especially from a first-floor cupboard. Ask whether disposal is included and whether any making good around the cupboard is part of the job.

What happens to the pipework?

This is where the questions get more useful. Old pipework can be divided into three rough groups: pipes that are removed, pipes that are capped and left, and pipes that remain live because they still serve something.

A good installer will trace the runs rather than simply cutting and hoping. Feed and expansion pipes from the loft tanks, the old cylinder flow and return, and any immersion-related wiring should be dealt with properly. In many cases, redundant pipework is cut back, capped, and left in the floor or wall where lifting it out would cause more disruption than it is worth. That is normal. What matters is that it is left safe, labelled where helpful, and not quietly connected to anything live.

Dead legs — sections of pipe that no longer carry water — are a particular point of interest. A short dead leg is usually harmless, but long runs of stagnant pipe are best avoided where practical. Ask how the installer plans to deal with them. The answer should sound like a plan, not a shrug.

If there is an old electric immersion circuit, it should be made safe and isolated. If the old system had a shower pump, a second immersion switch, or a timer in the airing cupboard, those bits need a decision too. Some can be removed; some may still be useful; some should be isolated and left for an electrician.

The loft: tanks, stands and insulation

Up in the loft, the old cold water tank and feed and expansion tank often become redundant. If they are removed, the space can be reclaimed. If they are left, they should not be left as a vague obstacle that nobody wants to touch.

Removal usually means draining, disconnecting, taking the tank out, and dealing with the stand or platform. Sometimes the platform stays because it is part of the loft flooring or supports something else. That is fine, provided it is stable and not quietly rotting. The pipework that fed the tanks should be capped or removed, and any holes in the loft insulation should be patched.

This is also the moment to think about the loft hatch and access. If the installer has to squeeze through a small hatch with a tank, the job may take longer, and the quote should reflect that. A clear loft with boards down is easier to work in than a fibreglass maze. You do not need to tidy it for its own sake, but clearing a path is genuinely useful.

Making good the airing cupboard

Once the cylinder is gone, the cupboard can become useful again — but only if it is finished properly. The first thing to check is whether any old pipework or wiring is still exposed. Capped pipes should be neat, not a row of open ends. Wiring should be isolated and, where necessary, removed by someone competent.

Ventilation matters too. Airing cupboards were often designed to stay warm and dry because of the cylinder. Without it, the cupboard can become a cool, slightly damp space if it backs onto a bathroom or external wall. If you plan to store towels or bedding in there, think about airflow. A vent or a small gap can make a difference; blocking every gap and sealing the door is not always the answer.

The floor and walls may need patching where pipes came through. This is usually cosmetic, but it is worth agreeing who does it. Some installers include basic making good; others leave it to you. Neither approach is wrong, as long as it is clear before the work begins.

Questions worth asking before the quote is signed

The best time to sort the aftermath is before the new Glow-worm combi goes in. Ask whether the cylinder, immersion heater, loft tanks and redundant pipework are included in the removal. Ask how dead legs will be handled. Ask whether the old immersion circuit will be isolated and by whom. Ask what “making good” covers — filling holes, patching plaster, refitting cupboard shelves, or nothing at all.

Also ask where the old equipment goes. A reputable installer will have a plan for disposal, and it should not involve leaving a cylinder in your front garden for a fortnight.

None of this needs to turn a straightforward combi swap into a drama. It is just the unglamorous side of a heating upgrade. The new boiler gets the attention, but the empty cupboard and the quiet loft are where a lot of the practical satisfaction lives. Get those details clear, and the space left behind can become a cupboard you actually use — rather than a dusty reminder of the system you used to have.