Matching a shower to your water system
More showers disappoint because of the system behind them than because of the shower itself.
Combi boiler
Mains pressure hot and cold. A thermostatic mixer works well. Flow is limited by what the boiler can heat, so running two outlets at once will show.
Unvented cylinder
Mains pressure with stored hot water. The best setup for a strong mixer shower, including multi-outlet and rainfall heads.
Gravity fed (tank in the loft)
Low pressure by design. A standard mixer will underwhelm. This is where a pump or a properly matched low-pressure valve earns its money.
Electric shower
Heats cold water on demand, independent of the boiler. Flow is always modest — that's physics, not a fault. Useful as a second shower or backup.
Common faults and what they mean
Runs hot then cold
Thermostatic cartridge failing, or another outlet stealing supply. On a combi it can also point at the boiler's flow sensing.
Won't get hot at all
Cartridge stuck on the cold side, an isolation valve closed, or an element gone in an electric unit.
Trickle from a good shower
Scaled head or hose first, then the valve filters. Rarely the valve body itself.
Damp on the ceiling below
Tray seal or waste, not the valve. Needs the tray checking for movement before resealing.
What you can safely check yourself
- Unscrew and descale the shower head and hose — the single most effective thing you can do about weak flow.
- Check the isolation valves on the supplies to the shower valve are fully open.
- Check other hot taps in the house. If they're fine, the problem is the shower; if they're not, it's the hot water system.
- For an electric shower, check the pull cord switch and the breaker before assuming the unit has failed.
- Never open an electric shower unit yourself — isolate it and leave it.
Repair or replace?
Thermostatic mixers are worth repairing while cartridges are still available for the brand — the valve body and the tiling around it are the expensive part, not the internals. Electric showers are less repairable: once the element or the PCB has failed, a replacement unit is usually cheaper than parts and labour, and the connections are already in place.
Shower trays are a replace, not a repair, if the tray flexes underfoot — resealing a moving tray will fail again within months and we'd rather tell you that than take money twice.
What it costs
Real North West ranges rather than headline prices. You get a fixed price for your job before any work starts.
| Job | Typical range | Notes |
|---|---|---|
| Thermostatic cartridge replacedWhere the part is available for the brand. | £120 – £240 | Where the part is available for the brand. |
| Shower head, hose and riser replacedCures many weak-flow complaints. | £80 – £160 | Cures many weak-flow complaints. |
| Electric shower replaced (like for like)Plus the unit; existing cable and supply reused. | £220 – £420 | Plus the unit; existing cable and supply reused. |
| Enclosure or tray resealProvided the tray is sound and doesn't move. | £90 – £180 | Provided the tray is sound and doesn't move. |
| Shower over bath with screenDepends on tiling and valve type. | £450 – £950 | Depends on tiling and valve type. |
| New shower enclosure and tray fittedTray, waste, tiling and waterproofing all vary. | Quoted on survey | Tray, waste, tiling and waterproofing all vary. |
Shower and bath plumbing — your questions answered
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