Mixer Shower FAQs

Does Gainsborough have a shower suitable for step modulating boilers?

Yes, our thermostatic valves may be connected to these systems but optimum performance is achieved with combination boilers which are correctly set up and fitted with a fully modulating gas valve.

Can I pump mains water?

No. Water Supply Regulations 1999 (Water Bylaws 2000 Scotland) do not allow shower booster pumps to be connected directly to mains fed plumbing. Also this being the case, pumped variants are not designed to withstand high pressure supplies.

What flow rate will I get from my mixer shower?

Flow rates will vary depending on what model mixer shower you decide upon, the type of water system and individual site conditions, e.g. inlet water temperature, size and length of pipe runs, fittings etc. The below can be used as a guideline only:

Gravity fed systems with a 1 metre head of water: 4-10 litres per minute.

Mains fed / high pressure systems at 3 bar pressure: 10-30 litres per minute.

What do I need to check most when selecting and installing a built in mixer shower?

What type of water system do you have?

Are my hot and cold water supplies balanced? Gainsborough's mixer showers cannot be used with a gravity-fed hot supply and mains-fed cold supply or vice versa. (Commonly known as mixed supplies).

Do you have a mixer shower suitable for a water system with high pressure cold water (direct from the mains) and low pressure hot-water (gravity-fed stored)?

Unfortunately, we don’t currently have a model suitable for this type of plumbing system.

There is a continuous flow or dripping from the shower head

This could be caused by water retention in the shower head. Heads and hoses retain a considerable volume of water once the shower is turned off and therefore water will expel from the shower head. To check for this:

  • For adjustable height shower heads - Disconnect the hose from the outlet end (opposite end of the head/rose) and examine if the water continuously drips directly from the outlet. If the dripping stops there is no fault with the shower or the shower cartridge. Ensure that your shower head is free from scale build up and that your hose connections are tight as these can also exacerbate this problem.
  • For fixed head showers - Unscrew the head from the arm and examine if the water continues to flow or drip. If water continues with the spray head removed, contact our Customer Services team for advice. NB, pre-1996 fixed heads (with grey rubber gaitor) do not have the facility to remove the head and check.

Depending on the type of water system in your home you may need to take different action:

  • For un-vented water systems - This system requires regular servicing in the form of recharging the air gap. Instructions are on the side of the Hot Water cylinder. If the air gap has been depleted this can cause a drip from the shower head. For advice on this, please contact your cylinder manufacturer.
  • For combination or multipoint boilers - The pressure may be too high. Our cartridges are designed to control static pressure to up to approximately 7 - 10 bar depending on your model. Note that pressures can increase at night by an additional 30%. If pressures do approach the maximum limit then a 'Pressure Reducing Valve' must be fitted. This also applies for pressure surges.

However, if none of the above relate to your problem please contact Gainsborough Customer Services by email or phone us on: 01959 560760.

Temperature fluctuations - no blend of water

- The hot and cold supplies may be reversed. Check supplies to ensure hot and cold are to the correct inlets.

- Supplies may be unbalanced. Check to ensure that supplies are from balanced sources. E.g. Gravity-fed hot water and mains-fed cold water. This is an unbalanced system and not suitable for a Gainsborough shower.

Fluctuating temperature or reduced flow rate

Try the following steps to solve the problem:

- The shower head or hose may be blocked:

  1. Descale the shower using a vegetable based descaler.
  2. Remove the hose and run the shower to establish if flow increases - if flow increases without the hose attached, the hose may be twisted or collapsed and will require replacing.

- Check for air in the system (Gravity-fed systems only):

  1. Remove the shower head from the hose (anti-clockwise) and place the open end of the hose at its lowest point (in the bath or shower tray).
  2. Set the temperature on the shower control to the MAXIMUM COLD POSITION.
  3. Turn the shower on.
  4. Gradually start to increase the temperature, slowly blending in the hot water. Keep doing this until you reach the maximum hot position. *Important: If at any stage the water pulsates, splutters or surges, stop moving the temperature control and wait till both the flow and temperature stabilise.
  5. Once you have reached the MAXIMUM HOT POSITION, keep it running on this setting for about 20 seconds (ensuring the flow and temperature are stable).
  6. Finally, do the opposite. Start blending in the cooler water, following the same procedure until you again reach the MAXIMUM COLD POSITION.

- Ensure the cylinder thermostat is between 50-65 degrees C.

- Check other outlets in the property are not being used at the same time as the shower.

- If on a combination boiler it may not be modulating properly.

  1. Check at another hot outlet in the property. The best one to test is at the bath tap.
  2. Fully open the tap and wait for a while, carefully check that the water temperature remains constant and at a good hot temperature. Any fluctuation at this outlet will identify the problem to be with your boiler.
  3. Another test is to open a hot outlet fully, run the water till the temperature remains hot and stable, reduce the flow on the outlet by approximately 30% and again wait for the temperature to remain stable. If the temperature is not hot or fluctuates, this could indicate a boiler fault.

The shower is running cold

- Check to ensure there is a hot supply available at your other hot outlets.

- Check for air in the hot supply and for a possible kinked hose. Refer to instructions in the fluctuating temperature or reduced flow rate section.

Can I use a cylinder flange when installing one of your showers?