Water Temperature I have a Mira mixer shower & the temperature has started to fluctuate. It is probably the mixer valve at fault but can I fix this myself, do I need any special tools or am I better getting somebody in to do it?

If your Bosch Highflow 21e hot water system is experiencing fluctuations in water temperature while showering, it could be caused by a few different factors. Here are some possible reasons for this issue:

1. Flow rate too high: The hot water system may not be able to keep up with the demand if the showerhead or tap is allowing too much water to flow through. This can cause the water temperature to drop suddenly. Try reducing the flow rate by turning down the tap or using a low-flow showerhead.
2. Water pressure fluctuations: If the water pressure in your home fluctuates, it can cause the hot water temperature to vary. This can be caused by various factors, such as other appliances using water at the same time, or changes in municipal water supply pressure. Installing a pressure regulator or a flow restrictor may help to stabilize water pressure.
3. Blocked or dirty water filter: A clogged or dirty water filter in the hot water system can restrict water flow, causing the water temperature to fluctuate. Check the filter and clean or replace it if necessary.
4. Malfunctioning thermostatic mixing valve: The thermostatic mixing valve (TMV) regulates the water temperature in the hot water system. If it's faulty or dirty, it can cause temperature fluctuations. A licensed plumber or technician can inspect the valve and replace it if necessary.
5. Faulty temperature sensor or control board: If the temperature sensor or control board in the hot water system is faulty, it may not be able to maintain a consistent water temperature. A technician can diagnose the issue and repair or replace the faulty component.

If you're unsure about how to diagnose or fix the issue with your hot water system, it's best to contact a licensed plumber or technician for assistance.

Shower Doctor TV: How to Service Mira 722 & Mira 723 ...

? 15:26
https://www.youtube.com/watch?v=MnTfj-8vA_Y
Jul 5, 2013 - Uploaded by The Shower Doctor
George services a cartridge inside a Mira 723 shower. ... Until I watched this, I was stuck with a half dismantled valve, no waterin the house and a .... Fresca Verona Stainless SteelThermostatic Shower Massage Panel ...

Shower Doctor TV: How to replace a Mira Excel cartridge ...

? 5:29
https://www.youtube.com/watch?v=bvng57EMQCI
Jul 1, 2013 - Uploaded by The Shower Doctor
George replaces cartridge inside a Mira Excel shower. ... Hi, I have this model of shower and turning the temperature selector to the hot side turns the ... I just got the place so cannot rule out incorrect shower installation but Im not sure if its ... to those with a booster pump in the loft how to turn off the water.

Fault Diagnosis: Support - Mira

The thermostatic cartridge is the part of the shower valve which control's the temperature of the water, therefore if there is a problem with the water temperature, the absolute probability points towards the thermostatic cartridge being at fault.

I would suggest you extract the thermostatic cartridge, remove any bits blocking water flow into the cartridge and then soak it in limescale remover. Put silicone grease on the O'rings. Install it again. If that doesn't work, the element within the cartridge could be faulty, so you could try replacing the element. If that doesn't work you will have to either replace the entire shower valve or replace the cartridge.

All of what I've said is based on the assumption that you are receiving hot water to your shower valve.

I've been working with thermostatic cartridge for many years and can tell you with confidence the above information likely applies to yourself. Shower Thermostatic Cartridge Spares

Is your cold supply to shower for some odd reason? How old is the device? warranty? persue that route. Customer service is usually helpful (they need to know about problems) .

sounds like either the cold water that feeds the other half got shut off, or the mixer in the valve for controlling the water temperature is broken....most likely the water got shut off. better go to the water source and trace the cold water feed pipe ,looking for a shut off valve....it could also be behind the shower panel, then turn or rotate the valve the other way and go test the water to see if you can adjust the temperature now.....if not, then replace your hardware.......in the mean time, you could turn the temperature down on the water heater so that you won't scald yourself in the shower til you have time to fix it properly.

Limit message is when the output water set temperature can not be reached, this is normally when the incoming hot water to the shower unit is not sufficiently hot. Service code 20 is something else inside the unit that is faulty, it could be a number of faults. Try reset Power down unit and re-start, it will either say Wait or Priming, after that it should restart, hopefully it will work. If not, you could have a internal fault with: The mixer valve/motor, the flow control valve or motor, the flow sensor. If you have hot water from other taps, then the mixer valve/motor is the most likely fault. If you only have cold water only from the shower head with limit message it could be the Hot solenoid controlled valve is faulty. Good luck as there are no spares available!

Sounds to me the diffusor is stuck or broken in the position to allow only hot water through it.Looks to me tou have a mixer valve on it. Might have to replace it.

Uue a 1/8" allen wrench to remove handle to access the dial that set's the mixture of water.Remember or mark where it is and remove and reinsert counter clockwise about a 1/4 turn to start to you reach desired temperature setting. Be careful not to set it at a hot enough setting to burn you.
Once dial in place slide handle on and turn on to check water temperature.

Your hot water must come from your coil in boiler and not from a seperate hot water heater - more then likely furnace hasn't been on for heating your house nor has it been on for any draw of hot water. You have to wait till it goes on and brings the water temperature up to your setting or get a hot water tank put in or a new type wall mounted gas instant hot water unit.

hi there, your boiler will perfectly match the mira excel ( a great choice i might add) a 24cdi will give about 9.8 litres a minute flow rate hot water.
The mira excel is suitable for any plumbing set up and there installation instruction are very well laid out & their helpline is fantastic.
The hot water will fluctuate accordingly to the time of year as the cold water temp coming into the property will vary. but the boiler will modulate to compensate.So in brief in the summer you will notice it hotter than you would in the winter, this has nothing to do with the boiler just the incoming temp of the cold water.

Kindly

Richie