Mira 415 shower + Vaillant ecoTEC plus 824 = cold showers...

[oriontc]

Hi all I have been living in my new home for around a year, during the summer the shower is fine, keeps warm/hot for as long as i need, i realise partly due to the fact it is naturally warmer too.... When it comes to winter the shower goes cold after around 3-4 minutes. at this point I have to then keep increasing the heat until eventually im at the max possible and even that goes cold a couple of minutes later.

the shower is a Mira Combiforce 415 EV and the boiler as described is a Vaillant Ecotec 824... I use the shower head on the economy setting so it should be the lowest flow possible.

the boiler is in the loft if that helps. also another thing i noticed is the bathroom tap takes a while to get hot and the flow seems to be very poor compared to the tap in the kitchen which can belt out water with some force.

I also noticed the boiler has a hot water and seperate radiator heat dial on the front. would increasing these help? or would that just make it get hotter and run out just as quick?

I'm pretty much a plumber novice so my knowledge is limited.

thanks in advance....

 

[picasso]

Turn the dial with the tap symbol up and see if your shower improves.

 

[Tipper]

Hot water should be set at about 65C.

What type of room stat/programmer do you have? Is it a Vaillant with outside temperature sensor?

 

[oriontc]

i turned the hot water up and it did seem to go up into the 60's on the boiler itself.

the programmer is a vaillant yes i can control the heating using it and it has a temp sensor. i never touch the "hot water, (pic of a tap)" side of it only the "radiator (pic of a radiator)" heating side which has no presets, it is manually controlled by me so if i set it to 18 degrees and the room temp is 10 then it will come on until it hits 18 then turns off etc.

I had a shower today a few hours after i changed the setting on the boiler and I didnt see any difference really. the shower still went cold after 3-4 mins, i then have to turn it up to max for it to get warmer again, 1-2 mins after that its cold.

I read you can recalibrate the shower by doing a certain sequence on the main dial, is this worth trying?

also if i added some kind of flow restricter, like the ones you get from the water companies, is this more likely to keep a steady flow of hot water?

 

[ianmcd]

when you run the HW tap in the kitchen does the water stay hot all the time or is it on off like the shower ?

 

[gigz]

Turn the shower on and go into the loft to see if the boiler goes on and off.

 

[oriontc]

ill try both ideas and get back to you when im home, cheers!

 

[oriontc]

i tested a couple of things today.

downstairs kitchen tap went cold after 2 mins, i left it running barely warm for the next 4 mins and it never picked up again when i turned the tap off after 6 total mins. i then left it for a good 5 mins turned it back on and more hot water came through.

i also tested the amount of water my bath and shower use. my bath used 9.75 litres of water in 1 minute using the hot water tap. my shower used 11.5 litres in 1 minute but I think the shower uses a mix of hot and cold water? so not sure how reliable that is, i had the dial turned up like 75% of the way, my usual temp when i have a shower.

the manual states the min water flow rate is 1.5 lites/min
the manual states the apr DHW flow rate at factory set temp rise (DT = 42 degrees) 9.6 litres/min
the manual states DHW flow rate T = 35 K rise 11.5 litres/min

no idea what all that means i just found every entry that seemed related to flow and litre/min

this might also be a good time to mention every 6 months or so the pressure drops in the boiler and i have to manually bring the pressure back up. not sure if related.

ill have to test the going up in the loft while shower is on when I have another person with me as its a pain in the .... getting up there in a hurry.

 

[ianmcd]

Try this, open the basin tap in the bathroom then go to the shower but dont turn on but move the temp control from hot max to cold then back again and watch the water flow from the basin tap to see if it alters if it does your shower cartridge is passing make sure the shower is not turned on when you do this

 

[oriontc]

The shower only has one dial. It turns on when you change the temp gauge so I can't change the temp without the shower being on? Unless I'm missing something

 

[ianmcd]

Sorry you are correct just looked at the shower you have and you cant carry out this test, unfortunately in my experience even some professional plumbers dont diagnose correctly a faulty shower cartridge, I usually find shower Doctor to be good but cant compare how they perform in other areas

 

[oriontc]

do you think it is the shower though? considering the kitchen tap goes cold after a couple of minutes too?

 

[ianmcd]

yes it could be as when the shower cartridge goes faulty it allows cold water to pass into the Hot side when the shower is not running, really need to know what the boiler is doing when the temps fluctuate

 

[The831Bunny]

Run the bath hot tap on FULL. Press the i button on the boiler (under the LCD display) and report back the code displayed when the water goes cold.

This will tell us what the boiler is doing at the fail point. The boiler should run continuously when supplying HW and not go cold. Sounds like the domestic heat exchanger may be blocked with debris.

 

[Tipper]

...

the programmer is a vaillant yes i can control the heating using it and it has a temp sensor. i never touch the "hot water, (pic of a tap)" side of it only the "radiator (pic of a radiator)" heating side which has no presets, it is manually controlled by me so if i set it to 18 degrees and the room temp is 10 then it will come on until it hits 18 then turns off etc.

...

If it has an outside temperature sensor then it will also be the type that sets the HW temperature too. Therefore the 2 knobs on the boiler should be turned up to their maximum and left there because they will be being overridden by the programmer settings.

Bunny will be the best to sort this out for you, follow his suggestions.