Worcester Greenstar Boiler - Hot Shower Water Issue

[iMark]

Hi all,

We’ve just had a new Mira Plarinum Dual Digital shower installed in the loft, feeding down to the bathroom upstairs which is great.

However, it has an error saying that the incoming hot water temperature is too low.

I’ve checked our Boiler (Worcester Greenstar 30i) and its set at 60 and other tap outlets do get really hot. The boiler isn’t too far away from the shower really so struggling to work out why it’s not reaching anything above 35 degrees to the shower incoming outlet!

First question is, I could try increasing the water temp to 65 but my boiler won’t let me set it past 60! Unless I’m going mad. Here is the pic:

Secondly, apart from putting some lagging around the small amount of exposed copper pipe in the loft to keep it warm, is there anything else I could try?!

It’s a really expensive shower that is potentially wasted now because it’s not getting the hot water temp it needs. Nightmare!

I have a Next thermostat controlling radiators but I don’t think it has Heatlink so don’t think I can control hot water temp from this.

 

[terryplumb]

Have you measured the temperature of the hot water ,at the shower and taps ?
I highly doubt you would get the temperature loss that you suspect if the boiler is putting it out at 60⁰C.
The pressure gauge for heating system is showing a little on the high side ,do you have a large number of radiators ? If it gets to the red section on the gauge the PRV will operate and dump water out the system.

 

[iMark]

Thanks for getting back to me!

This is what the Mira technician reported…

“
Unit in loft)

Hw pipe is only reaching 34•c before coming into the unit

45•c at basin and other outlets

Boiler pre-set at 60•c

No isolations on the inlet pipework only outlets

Potential issue with supply/pipework

Bathroom installer is coming to investigate

Can’t test for potential fault until hw temp has been met

Fault showing on ui - hot temp not reaching hot enough”


Just regarding the pressure gauge, this was actually much lower but one article said to fill more to see if that works but probably filled a bit much!

I mean, what else could be physically causing this temperature loss you think? The taps get proper hot.

I’m going to put some lagging around the pipes Brie lost to see if it helps retain heat but not holding out any joy with that.

 

[terryplumb]

Was the hot water pipe disconnected from the shower ,and allowed to run free to measure the temperature ?
If not ,how exactly was temperature established ?
I doubt the boiler is supplying 60⁰c hot water if you are only getting 45⁰c at most outlets.

 

[iMark]

No it wasn’t actually, the device the Mira rendition had seem to wrap around the copper pipe to record the temperature on the device from the looks of it!

That’s good that you think that - so it appears that it could be an issue with the boiler not sending out hot enough water then you think?

Thanks for your input, it’s really helpful!

 

[terryplumb]

Pity you didn't ask for the hot water pipe nearer to the boiler to have the temperature measured.
Whatever temperature the boiler is churning out ,doesn't explain the difference between what taps and shower are receiving.
There is not that many things that could cause that. One would be extraordinary long pipe runs from boiler to shower,compared to other taps ,another would be cold water entering the hot water pipe run to the shower. A thermostatic mixer valve on the pipe run for instance.
How old is the property?
Newer properties have a type of mixer valve where hot and cold are blended ,particularly on supplies to baths ,to give a preset maximum temperature supplied to the outlets ,to prevent excessively hot temperatures being delivered to kids,elderly, etc.
Do you know where the fitters picked up the hot supply from ?

 

[iMark]

I know, the engineer et Mira wasn’t proving helpful with me!

I’ve just spoken to the bathroom fitter who says there’s 100% no chance of cold / hot crossover contamination from his new pipework. Although, it would explain it and the cold tap in the bathroom sometimes initially feels warm when turned on until it runs ice cold after a few seconds.

He seems to think, the boiler pump isn’t strong enough to pump hot water to the loft but seems like my boiler could handle that surely (it’s a 4 bedroom house).

He recommends fitting a ‘Salamander Inline small pump’ to boost the power of the hot water.

1) Do you think it’s worth me paying for a plumber to look into doing this?

2) To answer your question about cold and hot water being blended in newer properties. Ours was built on 1985 - could this have a hidden ‘mixer’ blending hot and cold somewhere that wasn’t seen in the bath when the new pipework was laid down you think?

Thanks so much, this is really stressing me out, with the amount of money spent on this bathroom and shower!

 

[trojanhawrs]

That's a combi, the boiler "pump" is for central heating only, it feeds the shower at mains pressure. If there's plenty flow coming out the shower before it trips out on low temp I would venture that's not your problem. As terry says, you need to find out if the boiler is putting out what it says it is, and if so there must be a blending valve somewhere

 

[terryplumb]

Yes you could have a blending valve. If your bathroom fitter thinks a combi boiler pumps domestic hot water he isn't very clued up. Did you have a bath removed for the shower to be fitted ?

 

[iMark]

Thanks chaps, the most sense anyone has made in this whole disaster situation.

I know you’ll have zero idea to guess the answer to this BUT, surely this valve would be exposed somewhere for easy access / maintenance? The bathroom fitter would’ve seen it in the walls / floor when he ripped everything out so can’t be in there.

Upstairs seems to get much cooler with the hot water and downstairs is piping hot so that maybe tells me the valve is upstairs somewhere?

In your guys opinion, is it likely that I’ll ever find this thing, even if I paid someone to investigate its location. Sorry, total plumbing newbie! Any extra info would be appreciated.

It’s not near the boiler that I can see.

 

[terryplumb]

Did you have a bath removed for the shower to be fitted ?

Blending valves are often found under or close to a bath.

 

[iMark]

Thanks chaps! Ok, so update since your last messages but I’m posting this as I’m taking your feedback more seriously this this persons to be honest but worth your input for sure.

So, I asked him if he noticed a blender valve under the floor whilst he laid down the new pipe work (all walls and floor were totally exposed so would’ve been hard to miss). He said there zero chance it was there and that zero chance of accidentally joining hot and cold supply. When I asked him about whether he spotted a blender valve anywhere in the old fittings (we previously had a standard thermostatic shower in a bath) he said this:

“
That's not the case I'm afraid


Very uncommon to see in bathrooms unless its commercial building healthcare etc also it would be located above the floor just under the taps


Joining the hot to cold would course a lot more problems than a slight temperature change, mains pressure would push back to the boiler and most likely stop the boiler”


So, this leads me to a dead end until I get a plumber in to maybe check the recently serviced boiler for any issues or help maybe find the buried blender value if it’s maybe in one of the adjoining bedrooms.

Think this may be something we have to live with, what do you think?

 

[UpgradeME]

Joining the hot to cold would course a lot more problems than a slight temperature change, mains pressure would push back to the boiler and most likely stop the boiler

I would not trust anything he says, clearly doesn’t understand what he’s doing as the hot from a Combi is also mains pressure.

 

[terryplumb]

Since 2010 ( April) the building regulations ( Document G3 ,ammended) declared that ALL new build homes are obliged to have a device fitted to baths to limit the temperature of water delivered to 48⁰C( in England and Wales) . As your property pre dates this, it wouldn't have been compulsory in 1985 when it was built, that's not to say you don't have one ,but if you did it would almost certainly have been under the bath. Given what you have told us I think it's unlikely that the bathroom fitter wouldn't have seen it.
However ,he doesn't seem to know they have been compulsory since 2010 in new builds ,is under the impression that a combi boiler pumps domestic hot water ( which it certainly does not ),and apparently doesn't know that the pressure is exactly the same on combis hot water as it is on the mains cold, his plumbing knowledge is limited .
You need a plumber to visit.

 

[UpgradeME]

Not sure if it would cause your symptoms, however as the fitter thinks the hot water is pumped, wondering if he’s fitted the correct model of shower as there is a version for Combi and another for pumped systems. Do you have the product number for the shower on packaging etc?

The product numbers are at the bottom of this page: https://www.mirashowers.co.uk/platinum