Hot water System

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ronw

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#198547 13-Jul-2016 12:50

My hot water is not hot. I hate showers that are luke warm. I have a solar and electric cylinder 300 litres with two 3kw elements init (top and bottom) Current temperature is 57 at bottom and 65 at top. however the temperature coming out of hot water tap is around 43c. I am not sure if that is the Cleffi valve or if there is even one in the system I guess being solar you would have to temper somehow as on a sunny day it will get up to 75 C which you would not want coming out of the tap. Washing dishes I have to boil a jug to get enough temperature to clean them. My shower has two valves behind the wall one on hot and one on cold. I guess I can have a play with those for the shower to see if I can get it a bit warmer, but not sure what I can do for other taps. The sink and the bath are the two worst but cannot see any way to increase hot to either unless its behind the wall?

Any thoughts from anyone as best approach. I note that regulations say cylinder should be at least 65 c to kill Legionaires and that taps should be no hotter than 55 c at the tap to prevent scolding so somehow I need to get around a 10c increase

Thanks

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#1590971 13-Jul-2016 13:45

How are you measuring the temperates in the cylinder?

If you have low temps across the house, dollars to donuts the tempering valve on the output pipe of cylinder has failed/stuck and will need to be replaced....

ronw

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#1590974 13-Jul-2016 13:50

I have a temperature sensor inside cylinder at top and bottom courtsey of my solar system. Trouble is that it is fine when working off solar I get plenty of hot water but this time of year I need to rely on electricity and its not giving hot water. maybe time to get a plumber in to check it out

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timmmay

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#1591040 13-Jul-2016 15:18

You might have a mixing valve - not sure the exact name but my modern standard cylinder does. Turn that and the temperature at the tap changes, mixes in more or less cold water.

wellygary

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#1592055 13-Jul-2016 15:59

ronw:

I have a temperature sensor inside cylinder at top and bottom courtsey of my solar system. Trouble is that it is fine when working off solar I get plenty of hot water but this time of year I need to rely on electricity and its not giving hot water. maybe time to get a plumber in to check it out

It will be a stuck tempering valve, it will have stuck in the position to correctly mix the hot water temperature in the tank in summer (which is higher than winter) , now the tank is cooler the output to the rest of the house is also cooler,

Call a plumber, it will be an easy and quick fix for them to do....

ronw

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#1592069 13-Jul-2016 16:14

Thanks now to find a plumber. The first two are booked up for a couple of weeks.

Cheers

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#1592075 13-Jul-2016 16:27

Differential between tempering out and cylinder is 15 degrees so to get 55 out you need thermostat on 70 degrees.

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ronw

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#1592090 13-Jul-2016 16:40

Yup Thermostat is set at 70 which is the highest you can set it. So I agree with previous answer that it is most likely to be the Caleffi valve that has gotten stuck.

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#1592109 13-Jul-2016 17:35

IANAP but based on a quick look at a Rheem blurb the bottom element normally handles the heating. Your temp at the bottom of the tank is only 57? What is the thermostat for that element set at? On the Rheem tank only one element is active at a time.

ronw

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#1592170 13-Jul-2016 18:38

Its not a Rheem it's an HJ Cooper 300 litre Solar and Electric cylinder. It has two 3kw elements top and bottom each element is wired to a separate switch so you can have bottom, top or both on. I tried running both to see if that helped but it made no difference. The Solar is always on of course. Cold water in the bottom/ Temp at moment is 57C bottom and 62C at top. Of course Ripple control plays hell with the heating but that is offset by Solar even on a cold day Solar does add to heat.

I would have expect some drop off in temperature via piping but not to drop from 62C to 45C. I think previous answer is correct in that the Cleffi valve is not working correctly.

Incidentally its almost impossible to find an available Plumber on the North Shore. In the end I noticed a Genesis website that they have recommended trades people so I booked it via them and it has transferred the job to a plumber. Hopefully I will hear form them tomorrow.

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#1592219 13-Jul-2016 19:26

15 degrees is the normal drop off from a tempering valve and that's basically what you've got. Water needs to be hotter.

ronw

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#1592222 13-Jul-2016 19:45

If that's the case then we may have a problem. I have checked the thermostats on both elements and the max temp is 70 C which is what its set for. If we are not getting up that high it may be Ripple control not giving us enough time on. I should hunt down one of those devices that light up every time a Ripple signal comes down the wire.

Will see what a plumber recommends when he contacts me. It's only a pain at this time of year from September onwards I turn electricity off and just live on Solar which is plenty hot.

But then I dont really want such hot water at that time. I just like having hot showers and baths in Winter

C'est la vie

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#1592244 13-Jul-2016 20:48

The mixing valve sounds like the issue to me, you could put a thermomoter on the hot water outlet to measure the temp when someone is using hot water.

With water flowing turn the valve 1 way then the other, this might free up what is causing the blockage / issue, it might have a bit of gunk and turning the valve may free it.

You might have to do this two or three times and the valve should free up.

I am the same, I hate warm showers, love my hot shower.

If I had mains pressure and an infinity I never would get out of the shower :-)

John

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#1592253 13-Jul-2016 21:17

Many solar systems have a timer as part of the process. Winter/summer program etc. It may have a manual or boost button.

ronw

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#1592424 14-Jul-2016 11:39

Eureka!!! All solved. As someone suggested it was the tempering valve. Plumber came and wound it fully oof and then opened it fully. Temperature at tap is now 52 C which fantastic.

Thanks to you all for input and Dave I have made a n ote of that person you mentioned.

I feel like having a shower now just for the hell of it. Lovely hot water

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ronw

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#1592428 14-Jul-2016 11:41

Oh one more thing he explained how the tempering valve works. It has a wax strip inside that as it gets hotter it expands and restricts the flow. Ingenious must go find a bit more about tghat.

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