Solar HW, How Do You Manage It?

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tdgeek

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#220143 27-Jul-2017 17:04

With winter and the power company threads on here, appropriate to ask for feedback.

I love our Solar HW, it was in the house we bought early last year. As well as asking questions early on, I know now, how it works for us, so keen to see what others do.

Our Setup

300L Cylinder, top and bottom elements, unsure what size the tube panels are. Handy LCD display showing temps for Collector, Top of cylinder, Bottom of cylinder, transfer pipe, and what % pump is in use, plus other misc boring stuff

Our elements I'm told must be wired in serial as if I turn off the bottom switch, and leave top switch on, it does not heat via the grid. I assume if I turned off the top switch and left the bottom one on, it will only use bottom element?

The data that came with it, states that its a Solar HW solution with power backup, but IMHO and from real time use, its the opposite if left to its own devices. If the Collector is 8 degrees above the bottom cylinder, it transfers. But depending on usage patterns and weather, you can end up using the grid on sunny days, when showers bring cool water into the cylinder bottom, collector is not that warm, so the shower usage is topped up by the grid. Then the sun heats up water thats now not going to be used all day. Evening showers are free as the cylinder will be hot.

In summer, I turned the grid off for 5 months. As the weather changed, its back on, but I turn it off as and when the usage and the expected sun allows it. Ive had a shower at cylinder temp of 46.7, it was fine. As long as the water doesn't sit at mid 40's for an extended period, I assume Legionnaires is not an issue. Either due to time, or that the water has been over 60 already. Most under 60 showers are not much under 60.

My conclusion is that its great, but to maximise it, you should turn the grid off when usage patterns and sun allows, even in winter. I could get a timer fitted, but our usage isn't consistent, neither is the sun (ChCh) , so manual works for me. Im not studying it anally, and the LCD panel is very handy.

How do others manage it? Set it and forget it, or manually at times?

D.W

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#1832439 27-Jul-2017 18:36

I'm in a very, very similar situation to you.

Purchased house late last year (in Chch), solar on roof, 300L cylinder, top and bottom elements, Apricus Sentinel S6 Controller.

As we purchased the house just as summer was starting the bottom element was switched off when we moved in. It wasn't until Autumn this year that I noticed the hot water not lasting us a full day, and discovered the switch was off.

There is a second power switch which I think controls the top element, however it runs into a relay and I'm not sure what the relay is for exactly.

The collector temp seems to get nowhere near where it needs to be in winter, I'm not sure if this is as expected or if something else isn't right. However we manage to get by with hot water being heated from grid overnight only so I've just left it. I'll try switching it back off once spring/summer comes around.

I did notice on Tuesday? when we had really good weather that the collector temp was 60c, and I haven't seen it anywhere near that all winter.

tdgeek

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#1832464 27-Jul-2017 19:22

D.W:

I'm in a very, very similar situation to you.

Purchased house late last year (in Chch), solar on roof, 300L cylinder, top and bottom elements, Apricus Sentinel S6 Controller.

As we purchased the house just as summer was starting the bottom element was switched off when we moved in. It wasn't until Autumn this year that I noticed the hot water not lasting us a full day, and discovered the switch was off.

There is a second power switch which I think controls the top element, however it runs into a relay and I'm not sure what the relay is for exactly.

The collector temp seems to get nowhere near where it needs to be in winter, I'm not sure if this is as expected or if something else isn't right. However we manage to get by with hot water being heated from grid overnight only so I've just left it. I'll try switching it back off once spring/summer comes around.

I did notice on Tuesday? when we had really good weather that the collector temp was 60c, and I haven't seen it anywhere near that all winter.

Is your name Tony and your typing on your laptop at GZ right now??? Spooky!

tdgeek

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#1832465 27-Jul-2017 19:25

D.W:

I'm in a very, very similar situation to you.

Purchased house late last year (in Chch), solar on roof, 300L cylinder, top and bottom elements, Apricus Sentinel S6 Controller.

As we purchased the house just as summer was starting the bottom element was switched off when we moved in. It wasn't until Autumn this year that I noticed the hot water not lasting us a full day, and discovered the switch was off.

There is a second power switch which I think controls the top element, however it runs into a relay and I'm not sure what the relay is for exactly.

The collector temp seems to get nowhere near where it needs to be in winter, I'm not sure if this is as expected or if something else isn't right. However we manage to get by with hot water being heated from grid overnight only so I've just left it. I'll try switching it back off once spring/summer comes around.

I did notice on Tuesday? when we had really good weather that the collector temp was 60c, and I haven't seen it anywhere near that all winter.

Same here that day. It was sunny, I noticed that. I assumed that maybe the atmosphere was very clear, i.e. low smoke, moisture, that allowed a better solar effect.

By grid overnight only, what do you mean by that?

D.W

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#1832478 27-Jul-2017 19:52

tdgeek:

Same here that day. It was sunny, I noticed that. I assumed that maybe the atmosphere was very clear, i.e. low smoke, moisture, that allowed a better solar effect.

By grid overnight only, what do you mean by that?

Hot water cylinder is on separate electricity supply that only receives power for 8 hours overnight each night.

I was hoping that in theory that overnight heating combined with a bump during the day from the solar would be sufficient during winter, but instead we've found we just have to manage our hot water usage instead (which is mostly just for showers, making sure we don't spend excessive amounts of time in the shower (3 adults showering daily + a toddler who has the occasional bath)) as the solar isn't really doing any substantial heating at the moment.

tdgeek

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#1832484 27-Jul-2017 20:14

D.W:

tdgeek:

Same here that day. It was sunny, I noticed that. I assumed that maybe the atmosphere was very clear, i.e. low smoke, moisture, that allowed a better solar effect.

By grid overnight only, what do you mean by that?

Hot water cylinder is on separate electricity supply that only receives power for 8 hours overnight each night.

I was hoping that in theory that overnight heating combined with a bump during the day from the solar would be sufficient during winter, but instead we've found we just have to manage our hot water usage instead (which is mostly just for showers, making sure we don't spend excessive amounts of time in the shower (3 adults showering daily + a toddler who has the occasional bath)) as the solar isn't really doing any substantial heating at the moment.

I see, thought so. While 300l is large, it can be used up. We have 3 to 4 adults, that and sunny sunday washing with hot washes, can make a dent as it has here. My manual control does cover for that though. Its only about 3 hours to heat up from cool

Aredwood

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#1833560 29-Jul-2017 21:10

@D.W the relay for the top element is probably linked back to the controller. Some controllers have a "boost" function, where the controller will allow the cylinder to heat using the top element, then switch the element off when it is up to temp. Instead of leaving the top element to cycle on and off via the thermostat.

@tdgeek You might have tripped the overtemp cutout on the thermostat for the top element. Otherwise check to see if power is reaching it when the switch is on. As having the top element only on all the time in winter often works best. You always have hot water. And the bottom half of the cylinder still gets heated by the solar.

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tdgeek

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#1833624 30-Jul-2017 08:51

Aredwood:

@tdgeek You might have tripped the overtemp cutout on the thermostat for the top element. Otherwise check to see if power is reaching it when the switch is on. As having the top element only on all the time in winter often works best. You always have hot water. And the bottom half of the cylinder still gets heated by the solar.

Is the cutout inside the black plastic covers? Im not electrically minded, but they seem to be the top and bottom going by the location and cables. Being able to leave the top on in winter makes huge sense.

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#1834296 31-Jul-2017 13:15

Two person household (near ChCh), SHW does all the hot water in the summer, SHW will only heat system to 30- 40C in the middle of winter on a sunny day.

The system has two electric heating elements; one at near the bottom, the other 1/3 down from the top. There are two temperature sensors on the cylinder connected to the solar hot water controller. One near the top, the other at the bottom of the tank, and I can easily check these temperatures on the SHW controller.

To each electric heating element, I have two switches in series. The last switch before each element is an isolation switch (standard wall switch), the other switch in series, being used for control purposes.

Top element control switch is a simple push button timer giving one hour of heating and will then turn off. This gives sufficient hot water for two people to have a shower. Most of the time this is the only switch we use for supplementary heating. The isolation switch in this circuit is normally on.

Bottom element control switch is a 7 day digital timer, with manual override included. This is used for long extended bad weather periods, or when the house is full of people staying over. The isolation switch in this circuit is normally off. This means that the timer will blissfully do its thing (and keep its memory), but not turn the element on unless I deem it necessary by turning the isolation switch on.

System works well and has done for the last 11 years. Even as a home office household we only use around 5,600 kWh per year. I guess it could be improved by some GZ wizard developing a Raspberry Pi controller to read the Metservice forecast, check on the number of people in the house, water temperatures and then switch things on automatically so we never have to wait the 10 minutes for the water to heat up. Ha!

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#1834304 31-Jul-2017 13:28

My top element isn't working, as @aredwood suggests it may be a cut out by I cant see one inside the black plastic element (I think) cover. A plumber from a business that supports Apricus is coming Thurs to sort it, plus a few other bits and bobs. I'm wasting efficiency here

D.W

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#1860926 8-Sep-2017 14:04

tdgeek:

My top element isn't working, as @aredwood suggests it may be a cut out by I cant see one inside the black plastic element (I think) cover. A plumber from a business that supports Apricus is coming Thurs to sort it, plus a few other bits and bobs. I'm wasting efficiency here

How did you get on, did the plumber identify any areas for improved efficiency?

I've noticed in the last couple of weeks these sunny days have seen the collector temps getting up around 60-70c which is great.

tdgeek

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#1861029 8-Sep-2017 16:17

D.W:

tdgeek:

My top element isn't working, as @aredwood suggests it may be a cut out by I cant see one inside the black plastic element (I think) cover. A plumber from a business that supports Apricus is coming Thurs to sort it, plus a few other bits and bobs. I'm wasting efficiency here

How did you get on, did the plumber identify any areas for improved efficiency?

I've noticed in the last couple of weeks these sunny days have seen the collector temps getting up around 60-70c which is great.

All sorted! here is what happened

Plumber said top element is working, relay is working, so get sparky.

Sparky came, and spent a while trying to work out the wiring off the diagrams. Then he found the thermostat doesnt work, so replaced that

Si it now works correctly, which is bottom element is mains, I have it off or on if need be. The top element does not work 24/7. Its runs off a relay connected to a timer in the controller, so I have it set T1 (Timer 1) to 7am to 8am, T2 9pm to 10pm (EK free hour of power) and T3 off Its an ARR 3 which for Resol is 2 element cylinder (300l) and afterburner, which is grid topup. Nice solution as solar looks after the bottom and grid tops up the top.

Then the other day its not working! Called Apricus, Marcus said he thinks its a setting thats designed for Germany who have the thermostat located in a different way to us. The default is 40-45 but it was set totally different, which meant on some days the setting thinks no heat required, so changed that to 60-65 which means if temp is under 60, turn on relay/thermostat, if over 65 turn off. Did that and perfect now

Its hard to see how my collector goes compared to yours as mine transfers when the COL is 8 degrees higher then the bottom element, so as my bottom element is off, the COL might start the day at 16, bottom element 20, but on a sunny day ir heats it all up over a day, from pretty cool. But I do know that I can watch the COL rise, which is good. Right now, sun is out, the tenths on COL are like me counting slowly, its humming nicely.