Bristan Shower Problems (Bar Valves, Electric Showers)
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Post a job — we'll find you an engineer →For Bristan electric showers, isolate at the consumer unit before opening. For bar valves, close both service valves on the valve inlets before disassembly.
Bristan showers and bar valves are fitted in hundreds of thousands of UK homes, from new-builds to housing association properties, which means when they go wrong, you're far from alone. The good news is that most Bristan faults — whether it's a thermostatic bar valve that won't control temperature, an electric shower running cold, or a leaking cartridge — are straightforward to diagnose and fix without calling an engineer. This guide walks you through the most common problems and shows you exactly what to check and how to replace the parts yourself. Spare parts are stocked at every plumbers' merchant and online retailer, so you won't be left waiting. If you're uncomfortable working with electrics or isolating the water supply, or if the fault persists after following these steps, it's time to call a Gas Safe registered plumber.
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Most likely cause & what to check
Identify your Bristan product. Bristan makes both electric showers (the Bristan Bliss and Jump electric range) and thermostatic bar valves (the Bristan Prism, Assure, and Artisan ranges, widely fitted in housing association properties). The model name is usually on a sticker inside the cover (electric) or embossed on the body (bar valves). Bristan's customer support is at bristan.com or call 0345 026 0070 (Mon–Fri). Bristan spare parts — particularly cartridges and solenoids — are stocked at Screwfix, Toolstation, and Plumb Center, making Bristan one of the easiest brands to source parts for in the UK.
Bristan bar valve: temperature not controlling properly or stiff handle: the thermostatic cartridge is the cause. Bristan bar valves use a cartridge that sits in the left-hand (temperature) side of the valve. Close the service valves (quarter-turn on the inlet ports), remove the temperature handle (grub screw under a cap or Allen key bolt), and unscrew the cartridge retaining nut anti-clockwise with a spanner. Inspect the wax element for damage. Bristan cartridges are model-specific — the Prism uses a different cartridge to the Assure. Check bristan.com for the correct part number. Replacement cartridges typically cost £15–£35 and are a genuine like-for-like fit.
Bristan bar valve: water too hot even at lowest temperature setting: this is either a failed cartridge that is not restricting hot flow, or a cross-flow caused by a failed check valve. Bristan valves have WRAS-approved integral check valves as required by Water Regulations. Inspect the check valve cartridges in each inlet (remove the inlet connections to access them) — if the rubber seats are cracked, they are allowing hot to cross into the cold side. Bristan sells check valve service kits for around £8 per pair.
Bristan bar valve leaking from body or handle: leaks from around the cartridge nut indicate a worn O-ring on the cartridge. Replace the cartridge or just the O-ring (usually a standard BS1806 metric size — measure with digital callipers and source from any plumbers' merchant). Leaks from the inlet connections are usually a failed compression olive or washer — isolate, disconnect, and refit with a new washer or fresh PTFE on any threaded connections.
Bristan electric shower (Bliss, Jump): no heat or runs cold: isolate at the consumer unit, remove the cover (Pozidriv screws), and test the heating element with a multimeter across the element terminals. A healthy 8.5 kW element reads approximately 6 Ω. An open circuit indicates element failure. Bristan electric shower elements are available at Screwfix and Toolstation — confirm the kW rating before ordering. The element unscrews anti-clockwise with a 41 mm box spanner or element spanner, available from Toolstation for around £5. Wrap the new element's thread with three layers of PTFE tape.
Bristan electric shower: no flow or dripping after use: the solenoid valve diaphragm has typically failed. The solenoid is on the cold-water inlet inside the unit. With water off, remove the solenoid coil, extract the valve body, and inspect the rubber diaphragm — tears or distortion are the usual cause. Bristan solenoid service kits are widely available for around £8–£12. Also check the thermal cut-out (TCO) if the unit completely fails to start — on Bristan electrics the TCO is usually a white button on the heater tank, press to reset. For units under two years old Bristan offers a manufacturer guarantee — register at bristan.com.
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Frequently asked questions
Why is my thermostatic shower valve not holding temperature?
The thermostatic cartridge inside the valve contains a wax element that expands and contracts to balance hot and cold water — over time, this element can fail or become blocked by limescale, especially in hard-water areas. The cartridge is a wear item and typically needs replacing every 5–10 years depending on water quality. It's an affordable fix (£15–£35) and takes less than 30 minutes with the service valves closed.
My electric shower is running cold — do I need a new shower?
Almost certainly not — the heating element is a replaceable consumable that costs £20–£40 and lasts around 8–10 years depending on water hardness and usage. You can test the element yourself with a multimeter before ordering a replacement, and fitting a new one takes about 20 minutes once you've isolated the power at the consumer unit.
Is it safe to repair an electric shower myself?
Yes, provided you isolate the power at the consumer unit before opening the unit — this removes all electrical hazard. Once isolated, you're simply replacing a heating element or solenoid diaphragm, which are mechanical parts. If you're not confident locating the consumer unit or testing with a multimeter, call a qualified electrician to isolate the supply for you first.
Why is my shower leaking from the handle or around the cartridge?
Leaks from the cartridge nut are usually caused by a worn O-ring on the cartridge itself, which is a simple replacement (around £5–£10). Leaks from the inlet pipes are typically due to a failed compression washer or olive, which can be fixed by isolating, disconnecting, and refitting with new PTFE tape or a fresh washer — a five-minute job at most.