use of a mixer to regulate hot water temp

[wethead]

Hello everyone, I have a quick query for those in the know. I have an unvented hot water system and would like to know if i can use a 22mm mixer valve to regulate my hot water to a non scalding temperature from my tank and therefore increase the temp of the stored water?
Hope someone can help.
S

 

[stani]

why do you want to decrease the flow temp but increase the store temperature

 

[SimonG]

Upgraded a gravity system to S plan, set cylinder stat to 60. Jobs a good un. Cust is 100 yrs old but sorted through grand daughter. Live in carers look after her gran. Gets a call about frozen washing machine over winter, sorted, but carer complains about hot water temp, too cool. Some plank had turned cylinder stat down to 40. Apparently they turned it down because when she uses the loo and washes her hands the water is too hot and they are frightened she will scald herself. I said leave it at 40 and you won't have to worry about scalding, but you'll probably kill her through bacteria in the water. So stat back to 60 and tmv valve to wash basin hot water.

Is this a similiar scenario?

 

[Kimou]

I think they want to minimise parasitic growth and eliminate risk of scolding. There are temp restrictors you can fit which are regulation on new build installation now. Approx 38 deg, I think. To protect children and those of unsound mind and don't understand they are getting scalded or have an epileptic fit in the bath or scenarios along those lines...

 

[Puddle]

Think he is on about heating hot water to a higher temp than required then fitting a blending/mixing valve so cold mixes with the hot before the taps thus allowing hot stored water to last longer

There is no reason why this can not be done to increase your hot water storage capacity as long as non of the safety devises are tamped with,you may have trouble with these if cylinder thermostat turned up full and slightly out of calibration,how much extra hot water storage it gives you,do not know,a lot of factors involved,but the valve is not expensive and maybe worth a try if you find you are running out of hot water before you look down the bigger cylinder route or you are restricted with space

imho

 

[Kimou]

But just to inform you that there has been strains of legionella bacteria isolated at around 68-70 degree and surviving. Not common place, but it's been discovered. Very, very scary.

 

[Kimou]

Think he is on about heating hot water to a higher temp than required then fitting a blending/mixing valve so cold mixes with the hot before the taps thus allowing hot stored water to last longer

I didn't realise perceptional diagnosis reveals so much about a person. My logic was based on caring for croppers, and yours was caring for coppers haha such irony

 

[wethead]

Thanks for all the replies. I was wondering if anyone had tried it and if the 22mm mixer restricted flow. I have only seen diagrams for these connected to a single outlet rather than the multi output I am hoping to use. The advantages being that I can use a slightly smaller tank, nobody gets boiled or Legionella and the solar can add energy to the tank without varying the output temp. Or so the theory might go.

Thanks again

S

 

[SimonJohns]

You could effectively get "more" hot water but I doubt very much that you will save any gas or electric

The water will take alot more energy to heat up to 65+

If you run a bath just put the hot in first then cool it

Any failure will be poss more dangerous due to the higher temps

The more strain you will be putting on the tpv

And tons of lime scale so efficiency will reduce quicker with time and use

IMHO


Sent from my iPhone using Tapatalk

 

[wethead]

Thanks again for the replies. Nobody has told me its a bad idea so I think I will just have to put the mixer/blender on the hot out of the cylinder and see how it goes.

Thanks once more.

S

 

[SimonG]

Just one word of caution re the mixer. Make sure that in the MI's that its suitable for incoming temperatures in excess of 60. Most fittings, taps, showers, mixers I have seen all say not to be exposed to temps in excess of 65.

 

[mylesy]

its like a thermal store which has no way to control the water coming out, appart from fitting a mixer valve. its fine to do as you say in an ordinary un-vented set up. but id ring the local water supplier to find out about the limescale, if its suceptable to it then fit a descaller. but yeah you should be fine. sometimes good to fit a 3bar pressurised shock absorber if the mixer is non return.

 

[AWheating]

a tmv valve will do the trick, you can get solar rated ones if you need it for very high temps. make sure the cold side is balanced as most tmv valves dont work very well with more than 1 bar difference between the hot and cold.

you may want to consider running a non restricted supply to sink to enable you to wash grease down the sink without problems.

 

[wethead]

Thanks, thats just what I needed. Ill take the cold from the 3 bar cylinder pressure take off on the cold inlet. Theres no problem with limescale and i'll check the blenders max temp spec.

Thanks again.

S

 

[LegionellaSlave]

I wouldn't do this in a commercial property but maybe at home. Most blending valves have fine mesh strainers in the hot and cold inlets. Some have two strainers on each inlet and should be checked and cleaned every six months or following work on the system. Especially if there are appliances connected to the system that could create aerosols. (showers, spray taps etc)

 

[tackleburger]

Yes you can do this but I'd leave the cylinder at 60 deg anyway. It is good practise on Solar to crank the temp on the solar sensor to say 80 deg and fit a TMV thus utilising maximum solar gain.