What begins, in the innocent mind, as “a slight drop in water pressure” turns out, in the motorhome, to be a week-long descent into hydraulic purgatory.
It starts simply enough. A trickle at the tap. Nothing dramatic. One assumes a tired pump, perhaps a bit of scale, the sort of thing that yields in an afternoon with a screwdriver and a cup of tea. That illusion survives for approximately ten minutes.
Soon you are contorted in a cupboard clearly designed for a small, double-jointed apprentice, staring at a series of plastic fittings that appear to have been installed by someone working from the inside out before the furniture was fitted. Which, of course, is exactly what happened.
There follows the first lesson of motorhome plumbing: nothing is where a rational person would put it, and everything important is just beyond reach.
This particular episode is taking place alongside a separate, cosmetic campaign. The canopy departed some years ago, leaving behind a set of holes which have already been filled, sanded and persuaded back into something approaching respectability. What remains is the absence of the original pinstriping, missing now for a couple of years, giving the vehicle a faintly unfinished, post-operative look. The current ambition is to restore those lines, and with them a semblance of originality.
This, in turn, has required the small matter of finding the right paint. Not one colour, but two. A bluish red of indeterminate parentage, and a silver that appears to have been formulated in a laboratory now lost to history. What follows is a purchasing exercise of impressive inefficiency: selecting what appears to be the correct shade, applying it, discovering that it is not, and repeating the process several times at steadily increasing cost. By the end, one has accumulated a small archive of almost-but-not-quite reds and a selection of silvers that range from optimistic to frankly delusional.
Having finally converged on something acceptably close, the pinstripes themselves are applied with the aid of a newly acquired rechargeable airbrush. This airbrush is, naturally, justified as a necessary precision instrument for the task in hand, and therefore entirely reasonable. The fact that the airbrush may never be used again is beside the point. A new tool has been acquired, and that in itself is a form of progress.
Meanwhile, back in the cupboard, the investigation proceeds.
You begin, sensibly, with the pump. It must be the pump. Pumps wear out, pumps fail, pumps are to blame. A new, uprated unit is installed with quiet confidence. It produces, when liberated from the system and allowed to discharge into a bucket, a vigorous and entirely reassuring gush.
So not the pump.
At this point, the process becomes deductive. If the pump is sound, then the restriction must lie downstream. The flow is equally miserable at both hot and cold taps, which introduces a further refinement: the fault must be before the system divides into hot and cold feeds. One begins to feel almost professional.
The plumbing, however, remains unimpressed.
Leaks are discovered and remedied. Unions are replaced. Mysterious fittings are identified. Small plastic inserts, long ignored in a box of “interesting things”, are finally recognised as essential rather than decorative. Each intervention is logical, each step justified, and each one followed by the same thin, dispiriting dribble from the tap.
Progress, such as it is, takes the form of eliminating what is not wrong.
The layout reveals itself in stages. From the tank, the water passes through a 90 degree elbow, then into a filter, then through a pressure switch incorporating a non-return valve, and only then does it split into the hot and cold circuits. A neat, linear arrangement, at least on paper.
In practice, it has been assembled with a certain creative flair.
A 12 mm system, it turns out, has been thoughtfully “enhanced” with 14 mm components, connected via adapters that appear to have been selected on the basis of optimism. The result is a sort of hydraulic Brexit, where everything technically still connects, but nothing works quite as it should and the losses are felt everywhere.
The elbow is examined. Innocent. The filter is scrutinised. Slightly restrictive, perhaps, but not enough to explain the near-collapse of civilisation. Which leaves the pressure switch and its internal non-return valve.
A modest device, outwardly. It has a little adjustment wheel. It looks helpful. It is, in fact, the hydraulic equivalent of a border crossing that appears open, but in practice admits nothing at all.
One attempts to blow through it. Nothing. One dismantles it. Cleans it. Reassembles it. It improves slightly, in the way a blocked artery might respond to encouragement, but remains fundamentally opposed to the concept of flow.
The internal piston moves freely when prodded with a screwdriver, which briefly raises hopes. Air will pass, but only when the valve is forced open beyond what it ever achieves in normal use. Left to its own devices, it opens just enough to give the impression of cooperation, while quietly throttling the entire system.
At this point, a broader question presents itself. Why is there a non-return valve here at all. In a motorhome of modest length, the worst that can happen without one is that a small quantity of water drains back into the tank, requiring the user to wait perhaps a second longer for the tap to produce anything useful. In return for this marginal convenience, one introduces a spring-loaded obstruction directly into the main supply line, along with a fresh opportunity for failure. It is an elegant solution to a problem that barely exists.
By now, several days have passed. The job has expanded to fill the week, as these things do. There has been crawling, dismantling, reassembly, and the occasional philosophical pause to consider why any of this was arranged in such a way. Outside, the freshly applied pinstripes now sit where they should have been all along, the vehicle regaining some of its intended appearance, assisted by an airbrush that will almost certainly spend the rest of its life in a drawer, waiting for a second act that may never come.
Eventually, the truth is no longer avoidable. The pressure switch is not merely part of the problem. It is the problem. Not because it is broken in any obvious sense, but because it no longer opens sufficiently to allow the system to function. It is a perfectly good valve, in theory, that in practice behaves as a carefully engineered restriction.
It is removed.
And suddenly, astonishingly, water flows. Not as a trickle, not as a suggestion, but as something approaching a usable supply. Spirits lift. Conclusions are drawn. Victory is declared, cautiously.
And then the mixer tap is dismantled.
Out of the end of the spout, where one might expect to find the usual limescale, comes not calcification but a quantity of fine debris drawn from the archaeological layers at the bottom of the tank. It has travelled the length of the system only to lodge itself in the smallest and most determinedly restrictive point available, namely the outlet of a domestic mixer tap pressed into service in a motorhome. The same arrangement exists in the bathroom. Hot and cold, having travelled separate paths, reunite at the final moment to be throttled together in perfect equality.
Which explains everything.
The flow was poor on both hot and cold because, of course, they were not separate at all. They were being mixed and then collectively strangled by a component designed for a different environment, now acting as a highly effective filter for whatever the tank chose to surrender.
The debris is removed. The aerators are cleaned. The shower, previously a gesture rather than a function, now sprays with something approaching intent. The system, at last, begins to behave like a system.
There remains, it must be said, a slight sense that all is not yet perfect. The elbows are still there, the runs not as straight as they might be, the inserts only now making their belated appearance. These will be addressed in due course, in the spirit of finishing what the original installer began but did not quite complete.
The final lesson is simple. Motorhome plumbing is not complicated, but it is unforgiving of bodges, compromises, unnecessary components, and devices that almost work. Above all, it rewards a certain cold, methodical elimination of possibilities, even as it resists every attempt to be accessed or understood.
Still, there is a certain satisfaction in the end result. The system now works, the layout makes sense, and every joint can be reached without dismantling half the interior. It has taken the best part of a week to achieve what should, in a better world, have been right from the start. The vehicle, meanwhile, now looks as though it remembers what it once was, even if the airbrush that made it so is already quietly entering retirement.
It may be 24 years old, but with sufficient persistence, it can at least be persuaded to behave, and, with the occasional acquisition of entirely justifiable new equipment, to look as though it has never been anything other than entirely original (and last another 24 years).
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