Which mixer shower - thermostatic valve or not?

[TandC]

Looking at the options for our new shower arrangement...

 

On the old boat it was simple - the shower was fed from the Morco 61b gas boiler so we set the temperature on the boiler, and leave it alone.  There was a bog-standard mixer shower valve but the cold/hot inlet sides were fed from the same pipe coming from the boiler so no adjustment other than flow rate.

 

On the new boat we have a calorifier and so will need to run both a hot feed and also a cold feed to the shower mixer.

 

Lots of the mixer bar showers available are thermostatic - such as this -  https://www.wholesaledomestic.com/colore-brushed-brass-round-thermostatic-bar-shower-valve/ 

 

Is that going to work okay?

[magnetman]

I prefer to just have a hot tap and a cold tap and do the mixing manually. 

 

Had this on a narrow Boat which had calorifier and a paloma and it worked pretty well. 

 

i know there is a risk of excessively hot water but it didn't seem a problem. 

 

 

 

One of the current Boats has this which was fitted by the builder when they made the Boat as a vessel for hire. 

 

 

I am not well known as a fastidious user of such equipment. 

[ditchcrawler]

18 minutes ago, magnetman said:

I prefer to just have a hot tap and a cold tap and do the mixing manually. 

 

Had this on a narrow Boat which had calorifier and a paloma and it worked pretty well. 

 

i know there is a risk of excessively hot water but it didn't seem a problem. 

 

 

 

One of the current Boats has this which was fitted by the builder when they made the Boat as a vessel for hire. 

 

 

I am not well known as a fastidious user of such equipment. 

That is what I have but now wish I had fitted a thermostatic mixer. Only a problem in the winter, in the summer we don't turn on the cold tap as the water is not hot enough as we shower in the morning when getting up.

[nicknorman]

37 minutes ago, TandC said:

Looking at the options for our new shower arrangement...

 

On the old boat it was simple - the shower was fed from the Morco 61b gas boiler so we set the temperature on the boiler, and leave it alone.  There was a bog-standard mixer shower valve but the cold/hot inlet sides were fed from the same pipe coming from the boiler so no adjustment other than flow rate.

 

On the new boat we have a calorifier and so will need to run both a hot feed and also a cold feed to the shower mixer.

 

Lots of the mixer bar showers available are thermostatic - such as this -  https://www.wholesaledomestic.com/colore-brushed-brass-round-thermostatic-bar-shower-valve/ 

 

Is that going to work okay?

Yes a thermostatic mixer is much, much  better than 2 taps / manual flow control. Bearing in mind the calorifier hot water temperature can be VERY HOT expecially if you don't have a mixer on the calorifier outlet, then I would say it is pretty foolhardy to have a non-thermostatic shower whereby slight mismanagement of the taps could scald you badly. And even if you don't scald yourself, getting the right temperature is fiddly.

However the mixer you have shown is quite expensive considering there is no shower hose, head or rail  - as far as I can see it is just the bare mixer. You can get much better value from eg Screwfix for £75 upwards, although admitedly more if you are desperate for brass.

Edited December 20, 2023 by nicknorman

[Scholar Gypsy]

I have an identical unit to Magnetman (except it is installed with the taps above each other!).  

However the hot tap is connected to a cheap TMV that is installed near to the Carlorifier, and which mixes the very hot water with cold water to produce warm water to feed the shower and the bathroom sink. (The galley sink is connected to the very hot water, not least so I can fill up the kettle). It's worked perfectly for nearly 20 years.  As the schematic shows, I also added a bypass valve (W) so the pipework between the mixer and the taps could be drained.

Edited December 20, 2023 by Scholar Gypsy
Incompetence

[IanD]

If there's a thermostatic mixer on the calorifier (there usually is) it's normally set to something like 50C to prevent scalding from taps, the calorifier can run a lot hotter than that (e.g. 85C) especially if being used to store excess solar power.

 

This is still too hot for a shower for most people, an adjustable thermostatic mixer on that is normally set to no more than 40C. It also helps prevent the anguished "Aargh!" when somebody turns a hot or cold tap on elsewhere in the boat while you're showering... 😉

 

The shower on my boat is a standard domestic Mira one with a thermostatic mixer, which works very well.

 

 

[Tracy D'arth]

Thermostatic always. You only need one scalding to a child or older person to convince you of the necessity. Then its too late.

43 degrees is the recommended maximum setting for shower valves.

[magnetman]

 

I find if I have a shower at 60 degrees Celsius it is so effective that I don't need to use it again for 6 months. 

 

 

 

[Sea Dog]

We have a single lever non thermostatic mixer valve on the boat.  Never had a temperature stability issue and it's easy to drain down the shower valve in winter so that's the ideal solution in my book... providing there's a thermostatic mixer limiting the temperature of the hot water leaving the tank. Whilst you need to store hot water at a high enough temperature for the prevention of Legionella or even higher for practical reasons, there's no need to expose the end user to this unsafe temperature. The thermostatic mixer on the outlet will prevent that for you at both your sink and shower so, if you have that set up, you don't really need a second thermostatic mixer at the shower valve. (Unless you contest that just one thermostatic mixer isn't safe enough when you can chose to have both - then once you're dry you can put on your trousers with a belt and braces). 

[nicknorman]

2 hours ago, Scholar Gypsy said:

I have an identical unit to Magnetman (except it is installed with the taps above each other!).  

However the hot tap is connected to a cheap TMV that is installed near to the Carlorifier, and which mixes the very hot water with cold water to produce warm water to feed the shower and the bathroom sink. (The galley sink is connected to the very hot water, not least so I can fill up the kettle). It's worked perfectly for nearly 20 years.  As the schematic shows, I also added a bypass valve (W) so the pipework between the mixer and the taps could be drained.

However if the hot water supply to the shower and bathroom sink can only supply “very warm” water, this creates a legionella risk. Probably not going to happen, but if it did it could kill you or your loved ones. So my point is that that setup is not ideal.

[magnetman]

Nobody is going to get scalded if they turn the cold tap on first. 

 

Its an easy rule to stick to. 

 

People would have been alarmed by the system installed on a narrow Boat I had. Calorifier and Paloma in the Same Circuit and individual taps for the shower not only that there was a pump for hot water and a pump for cold water. 

 

No TMV anywhere. 

 

Cold water pump blockage or fuse blowing get out quick! 

 

If you can't stand the heat get out of the shower. 

[TandC]

Grand - thermostatic it is.   Thanks

 

 

[ditchcrawler]

7 hours ago, TandC said:

Grand - thermostatic it is.   Thanks

 

 

But don't let it freeze

 

[Tracy D'arth]

Never let any brassware freeze, it will crack.  It is to be sure that hot and cold are fully drained, the non return valves make it a little more tricky. I have an exposed bar type stat mixer and I undo the nuts when draining down.

[magnetman]

Do these freezing events actually happen on Boats? 

 

I've had a variety of different Boats with full domestic services for 30 yars and they have not always been occupied or connected to services. Never once drained anything down. Palomas, calorifiers, pipes and pumps nothing has ever frozen and caused problems. 

 

My theory was that being in water caused some sort of thermal phenomenon where the items in the Boat never get that cold. 

 

I wonder if talk of things freezing are apocryphal tales. 

[ditchcrawler]

22 minutes ago, magnetman said:

Do these freezing events actually happen on Boats? 

 

I've had a variety of different Boats with full domestic services for 30 yars and they have not always been occupied or connected to services. Never once drained anything down. Palomas, calorifiers, pipes and pumps nothing has ever frozen and caused problems. 

 

My theory was that being in water caused some sort of thermal phenomenon where the items in the Boat never get that cold. 

 

I wonder if talk of things freezing are apocryphal tales. 

I had a joint go a few years back, didn't find out until I went to flush  the loo but actually flushed my foot, I have known of one calorifier for sure and a few gas water heaters. I have also heard of shower mixers going but never seen one first hand 

[IanD]

6 minutes ago, ditchcrawler said:

I had a joint go a few years back, didn't find out until I went to flush  the loo but actually flushed my foot, I have known of one calorifier for sure and a few gas water heaters. I have also heard of shower mixers going but never seen one first hand 

Were these on boats with frost protection heating?

[Onewheeler]

30 minutes ago, magnetman said:

Do these freezing events actually happen on Boats? 

 

Yes. Had a burst pipe in the feed to a shower (buried right in the middle of the boat where it was in a less exposed location, before I realised that the NRVs had stopped it draining) and a probable knackering of a thermostatic shower (which was dismantled, reassembled with some bits left out that I couldn't understand the location of, and continued working).

[ditchcrawler]

1 minute ago, IanD said:

Were these on boats with frost protection heating?

No, boats that got cold

 

[IanD]

1 minute ago, ditchcrawler said:

No, boats that got cold

 

Same problem as burst pipes in unheated empty houses then, no surprise there... 😞

[ditchcrawler]

22 minutes ago, IanD said:

Same problem as burst pipes in unheated empty houses then, no surprise there... 😞

Correct, well it was to me, because I thought I had drained everything but left water in the short length between the valve and the toilet. The statement was in reply to Do these freezing events actually happen on Boats? 

[magnetman]

Maybe I have just been lucky and to be fair I have never had a Boat as a leisure use item. I have had one of the Boats completely covered in snow and the canal iced up and remained unused for a few days but nothing bad happened.

 

 

 

 

[Ex Brummie]

29 minutes ago, magnetman said:

Maybe I have just been lucky and to be fair I have never had a Boat as a leisure use item. I have had one of the Boats completely covered in snow and the canal iced up and remained unused for a few days but nothing bad happened.

 

 

 

 

Just be aware, your freeze up is one day closer every day. I have had a heat exchanger freeze on a Main Nymph in  cruiser, many years ago, and latterly the pipe from the water section to the heat exchanger on a Vaillant multipoint. Last year, I had a central heating pipe blow a joint where draining down obviously left a pipeful of antifreezed water.

maybe all the hot air produced in London has saved you.

[magnetman]

I'm banking on the global warm bin to sort it all out.

 

Plus the Boat most at risk is on the Thames which probably does have a thermal effect on the internal services.

And yes the London Boat is probably warmed by surrounding buildings but I had boats for 20 yars in nice places before arriving in this hellhole.

 

[Laurie Booth]

On 20/12/2023 at 14:25, TandC said:

Looking at the options for our new shower arrangement...

 

On the old boat it was simple - the shower was fed from the Morco 61b gas boiler so we set the temperature on the boiler, and leave it alone.  There was a bog-standard mixer shower valve but the cold/hot inlet sides were fed from the same pipe coming from the boiler so no adjustment other than flow rate.

 

On the new boat we have a calorifier and so will need to run both a hot feed and also a cold feed to the shower mixer.

 

Lots of the mixer bar showers available are thermostatic - such as this -  https://www.wholesaledomestic.com/colore-brushed-brass-round-thermostatic-bar-shower-valve/ 

 

Is that going to work okay?

This is what I have and very glad I chose it.

 

Rize Exposed Thermostatic Mixer Shower Valve Fixed Chrome - Screwfix