Redring [Filter or handset filling with solid material]what to check

This is the one entry in the Redring guides that points away from the appliance entirely, and it is worth a page precisely because the answer is counterintuitive. The question they publish is about a filter or handset that keeps blocking or filling up with solid material, and their answer is a diagnosis rather than a remedy: following the initial installation, no solid materials should remain in your cold water supply or the electric shower unit, so there is a problem with your water supply, and you should contact a plumber for advice. That is a manufacturer declining to treat a repeated blockage as a shower problem, and they are right to. A shower filter is there to catch the occasional particle.

If it fills, something upstream is producing a continuous supply of debris, and the candidates are all in the plumbing rather than in the appliance: a corroding galvanised pipe shedding scale and rust, a perished washer or a disintegrating flexible hose liner breaking up inside the pipework, disturbed sediment after mains work in the street, or debris left in the system from a recent installation that was never properly flushed. Fitting a new filter, or cleaning the same one every few weeks, treats the symptom of somebody else's problem.

The reason it matters beyond the inconvenience is that the debris is not stopping at the shower. Everything else fed from the same cold supply is receiving it too, and in a shower specifically it is the thing that goes on to block the handset, throttle the flow, trip the thermal cut-out and eventually burst a pressure relief device. So Redring sending you to a plumber is not a brush-off. It is the correct escalation.

1. 1

   Look at what you are actually clearing out. Grit and scale suggest pipework; black or orange rubber fragments suggest a perished washer or hose liner upstream.

2. 2

   Check whether other cold outlets are affected. Debris at the kitchen tap aerator as well points firmly at the supply rather than at the shower.

3. 3

   Ask whether there has been recent work — plumbing in the house or mains work in the street. Both disturb sediment and both settle down after flushing.

4. 4

   Clean the handset again, and have the inlet filter cleaned at the same time, so you have a clean baseline, then note how long it takes to fill. Days is very different from months.

   Redring’s filter instructions have the electricity off at the isolation switch and the water off at the isolation valve first, and say it is essential the job is done by a competent person. If it means removing the front cover on your model, their self-help page says to seek the help of a qualified person.
5. 5

   Get a plumber to look at the supply, which is Redring’s own instruction. Repeated blockage is a symptom of the pipework rather than a fault in the shower.