Noisy mira platinum digital shower

[moneypenny]

Can anyone help with this problem.

I have had a Mira platinum rear fed digital shower fitted, it was connected to electric and commisioned on 20 December. Worked OK but it was only tried without shower head.

The first time I used it, seemed to work Ok, then next morming heard very loud vibrating noise ( I can feel the vibration travelling down the flexible hose) and the flow and temperature began to pulsate and fluctuate respectively. After running it for a few minutes and switching the shower on and off it seems to work perfectly until the next morning. I don't know if this is relevant or coincidence but the noise started immediatly after I had experimented with the different shower head fittings.

I have a Worcester Bosch 30si boiler just a few months old which works perfectly so do all the taps. The boiler is situated in the loft about a couple of metres from the mixer. I don't know if flow regulaters were fitted if Mira don't provide them with shower I would say not. I wonder if the noise is the feed pipe situated in the cavity wall, could it be air in system and if so is it easily fixable. Mira technical are closed now until after new year.

Any help, Please.

 

[moneypenny]

Mira engineer called for the above problem, seemed stumped, called his 'tec guys' who suggested changing the mixer valve, 1. it might solve the problem 2. it means because the valve has been changed, the shower is very new, and they cannot offer a diagnosis for the problem the customer will not be charged £73 call out.

Changing the mixer valve solved the problem, the noise and pulsating flow rate stopped.

However, the shower now starts great nice flow, nice and hot, but the temperature gradually decreases then the flow rate gradually decreases ,sometimes to a trickle. Switch off the shower then on again and the pressure is so good it shoots water to the the other side of the shower cubicle, and very hot, then gradually decreases again. In short inconsistent temp and flow. Didn't get a reply to my first post which is unusual on this site so I guess these showers are not the norm.

The water board say my pressure is set at 1.5 bar and my boiler pressure is set at 1.5 bar when cold. the hot water in the taps is consistent and very hot.

 

[Pavo]

Fitted a mira platinum un pumped version, im also having the same vibrating problem, do i just need to call mira and arrange replacement.

 

[moneypenny]

Pavo

If the shower is under guarantee and the valve is faulty then mira will come out within a couple of days and replace it free. Not really sure what was causing the noise and vibration mira thought it could be an air trap but changing the mixer valve fixed it, give them a ring on 0844 571 5000 I have found their customer care very good.

Unfortunately when that was fixed my temperature was still fluctuating so they booked me another service call. They have put it down to a low flow problem, it seems I have had bad advice from the plumber who fitted the boiler which requires mains water pressure of at least 2 bar to operate at full flow which even full flow is only 10l/min my mains pressure is set at 1.5 from the boundary and it is shared!! He did no checks! worcester bosch say I should have had a 38kw. He left all instructions in the loft and hasn't completed the benchmark checklist. If I had done this research before having the boiler installed I wouldn't be in this position now.

The mira will work on a 5l/min flow rate (mine to the shower is about 7.5) but requires 1 bar pressure. Mira have set my flow rate in the wireless control unit at 99 I get a great shower for 1 or 2 mins then cools off a little but it doesn't go completely cold. could have kept had my gravity fed back boiler and had a pumped shower, although I have to say the central heating greatly improved.

 

[Pavo]

Many thanks moneypenny

Ive called customer sevices who were very good, engineer will ring to arange a visit, tested shower and i get 11 ltrs minute so hopefully they will just change faulty valve and all wil be well.

 

[moneypenny]

11 seems ok, I have a flow problem and my flow has to be set on max in the controller as I said, but at the moment the ambient temp in my loft is obviously not good and my boiler only has a 30 degree rise so my shower this morning took ages to warm up even though the pipes are well insulated.

The water board tested flow/bar pressure from my outside tap at a good 3 bar or 30 metre head and flow at 17lmin So my boiler should be able to cope with 10.7l/min. But I am only getting that from my downstairs hot tap. So even if the pressures had been tested before installation I would probably still be up the creek.

Have a plumber coming to look at installation see if anything can be done to improve flow, he has 2 digital showers but not on a high pressure combi! he installs Mira Excell with these boilers and has never had an issue, so may have to swap because I can't live with this high spec poor performing shower every winter, (when temp are not this cold the shower is ok.)

Good luck interested to know how you get on.

 

[Pavo]

Well engineer visited this morning and didnt know what the problem was, changed valve in the box then went but shower is still vibrating for a couple of minute when first turned on @42deg, if i turn the shower down to about 38 deg for 2 mins then back up to 42 its ok, ive tested the flow rate from the head of the shower and its 11 ltr a minute, the boiler is a baxi 105 30kw, temp seems fine!
Moneypenny yours seems a strange problem with the boiler being so close to the unit you should be getting a nice hot shower, what temp do you have the hot water set to on the boiler, Also you mentioned flexi hoses, are these connected to the unit, if so might be worth checking they are high flow ones, other than that if all the taps are getting hot then it has to be the shower unit,

Im going to have to arrange another visit all that is left is changing the control board, i cant think of any thing else and judging by the engineers help mira cant eather

Cheers let me know how you get on

 

[moneypenny]

When they changed my valve the first time I switched it on it pulsated and made a noise for a couple of secs and my heart sank but it hasn't done it since. I wonder if they unknowingly cleared an air lock when they changed the valve in which case I have a perfectly good one in my cupboard they left.

I have had a hot shower every morning except for one since the mira tech guy reset my remote controller to max for everything, except for one that was just warm.

I don't have flexi fittings on the pipes going to the unit just 2 isolator valves and two push fit bends on both the hot and cold feed but the bathroom installer raised the unit to give clearance to the gas feed so it is about 3"higher than the connections to the boiler and at it's highest point before it levels out and hits the valve it has a bend. Mira say this shouldn't make a difference with a high pressure combi but I need every bit of pressure I can get.

There is flow regulator in the valves warm inlet which is supposed to reduce the flow to 9l/min but I am only getting 7 or 8 litres the installation guide says reduce 25k to 7l and 30k to 9l any boiler above 30k it shouldn't need to be fitted . The guy from Mira says don't remove that, it is factory set, how can it be factory set when they don't know what boiler you have. I know nothing about plumbing as you can probably tell just on steep learning curve at the moment.

I only have what I have coming into my house so not optimistic, could be a preloved, little used Mira digital remote and mixer valve up for auction soon It isn't right but I will carry on with it and see what happens when the weather warms up. I have been put in touch with someone quite local to me who has been plumbing for many years and is well recommended, has offered to come and have a look if I get sick of it, he didn't sound optimistic when I spoke to him. If it cannot be improved I will swap the valve for a mira excel which only requires 0.01 bar. Mira say the riser,shower head and hose are all compatable with excel and the valve is on a stud partion wall. I am on a water meter so a less powerful shower has it's compensations.