Shower temperature problem

[richard242]

I have two showers at first floor level fed by a Worcester Combi boiler. Both showers are Mira Agile thermostatic mixer showers and are fed from the same hot and cold supply runs. One shower has been in for approx 2 years and at the moment is working fine. I had temperature fluctuation problems with the other (which has been installed for about 4 years) about 8 months ago and replaced the cartridge and the filters. At first the new cartridge did the trick, but I'm getting the same temperature problems again now, and I notice the boiler is cycling as the shower temperature goes up and down. As the newer shower is working ok I assume the problem is not with the boiler. I am wondering if the replacement cartridge is the culprit? Any thoughts/ other suggestions would be appreciated. Many thanks.

 

[Chuck]

Check that the shower is plumbed in correctly, i.e. hot water is going into the correct inlet. If the ports are reversed the temperature setting will be very sensitive and will tend to swing between extremes of hot and cold.

If it's not this, the next most likely cause is insufficient flow causing the boiler to cycle. Set the the flow rate by timing how long it takes to fill a jug or small bucket.

If plumbing is okay and flow rate is consistent and within spec, then I'd suspect the cartridge.

 

[richard242]

Check that the shower is plumbed in correctly, i.e. hot water is going into the correct inlet. If the ports are reversed the temperature setting will be very sensitive and will tend to swing between extremes of hot and cold.

If it's not this, the next most likely cause is insufficient flow causing the boiler to cycle. Set the the flow rate by timing how long it takes to fill a jug or small bucket.

If plumbing is okay and flow rate is consistent and within spec, then I'd suspect the cartridge.

Thanks, Chuck
The pipework is plumbed in ok, and the flow rate when I turn full on is good (although the temp is cold until I reduce the flow considerably). I will double check the flow rate however as you suggest. If all checks out would seem to be the cartridge then. This will be the third cartridge for this shower -is there anything that can cause cartridges to wear out sooner than they should?

 

[Chuck]

This will be the third cartridge for this shower -is there anything that can cause cartridges to wear out sooner than they should?

If replacing the cartridge fixes the problem, you should be able to return the one that failed after 8 months under warranty.

Did you replace the original with a 'genuine' Mira part from an authorised stockist or some cheaper 'equivalent' from eBay? Is your water very hard, or acidic, or from a private source? Did you flush the pipes to ensure there was no grit or blockage before installing?

 

[richard242]

If replacing the cartridge fixes the problem, you should be able to return the one that failed after 8 months under warranty.

Did you replace the original with a 'genuine' Mira part from an authorised stockist or some cheaper 'equivalent' from eBay? Is your water very hard, or acidic, or from a private source? Did you flush the pipes to ensure there was no grit or blockage before installing?

I got the replacement cartridge from MIRA, so it should have been ok. The water is quite hard where we are, but I have a softener, and the other shower doesn't seem to be affected. Yes the pipes were well flushed before fixing the shower mixer. I have made contact with MIRA re the situation and am awaiting their reply. I'll let you know how I get on...