My unit starts running the pump early parts of morning when the solar collrctor is 4 degrees and geyser is 30. Shouldn't it only run if the collector is higher than the geyser and mine is set st 7deg. During the day the pump works unusually often. The pump will work for about 4 times before the values can change and by 1 deg only.My electricity bill is 2k more for the last 2 months and I'm sure it's related to this.

Bad pump or setup issue?

Hi Vish999

The pump will start running if the collector falls below 5 degrees to stop the collector from freezing. It will run the hot water from the geyser to warm the collector.

The heating of the geyser is done in small increments, as the collector is significantly smaller than the geyser. In winter, it also takes longer to heat the collector.

If you are using the hot water all the time, the element will also switch on at the same time as the pump, which will heat the water faster, but at the same time also affect the collector's effectiveness.

You could switch off the element, but it will take much longer to heat the water and not keep the set temperature if you are using a lot of hot water.

I was looking at the same problem, and now I understand how it functions.

I hope this will help.

Edited June 30Jun 30 by Peter Topp

18 hours ago, Peter Topp said:

Hi Vish999

The pump will start running if the collector falls below 5 degrees to stop the collector from freezing. It will run the hot water from the geyser to warm the collector.

The heating of the geyser is done in small increments, as the collector is significantly smaller than the geyser. In winter, it also takes longer to heat the collector.

If you are using the hot water all the time, the element will also switch on at the same time as the pump, which will heat the water faster, but at the same time also affect the collector's effectiveness.

You could switch off the element, but it will take much longer to heat the water and not keep the set temperature if you are using a lot of hot water.

I was looking at the same problem, and now I understand how it functions.

I hope this will help.

Hi Peter. This makes sense to not freeze the collector. So this shouldn't happen out of winter. Do you think the pump(12v) could contribute to the electricity usage increase?I have a watt plug so I can connect this if it's merely a plug from the unit. Thanks .

Hi Vish999

You asked if the solar pump could cause the high power usage.

The 12VDC solar pump uses less than 100W of power, so it is not the culprit.

I can tell you what the problem is with the high power usage.

Three weeks ago, I had my 150L geyser with twenty brand-new retrofitted solar tubes replaced as my old geyser leaked, and some of my old tubes were cracked.

I also replaced the 3KW element with a 2KW. I did this for four reasons.

1. My house has a granny flat that also has a 150L geyser. With two geysers, the power usage at one time, with all the other appliances, can be a problem for me.

2. I also have one geyser coupled to my inverter as my whole house (not the flat) is on the inverter.

3. The Geyserwise controller uses a relay to switch the element on. Lower current will help the relay to last longer with constant switching.

4. The most important reason is that I have the solar tubes. The 2KW element will take longer to heat the geyser, and it gives more time for the collector to heat up and to circulate the water when both the element and the solar pump are on.

I always knew that my old solar tubes did not help at all in Winter.

With your post, I had a closer look at my system efficiency.

This is my conclusion.

When I woke up this morning at 5:45 am, the geyser water was 50 degrees, and the collector was at 8 degrees, heated by the element.

My wife had a long shower at 8:30 am. The readings before the shower were geyser 47 degrees and collector 9 degrees. After the shower, the geyser read 19 degrees, and the collector stayed at 9 degrees.

I checked intermittently, and the solar pump never switched again the whole day as the delta was never above 7 degrees for the pump to switch on. The maximum the collector reached was 46 degrees, which is well below the set temperature of 50 degrees.

If I had switched off my element, I would only have cool water at any time, never reaching the geyser's set point of 50 degrees.

My conclusion is that in Winter, the solar tubes do not help much if you are using a fair amount of hot water during the day, as the element will always do most of the heating.

I have seen the pump and collector keeping the geyser temperature at the set temperature, but not today.

I know that in Summer the solar tubes work much better.

I am sure this is the same problem I have.

How the Solar geysers are advertised, and reality is quite different.

Fortunately, I do have a gas geyser backup if all else fails. I also added an extra 4KW of solar panels so that I run my geyser on mains through the inverter.

I hope this explanation gives you and others a better insight into why your power bill is high, even though you have a solar geyser.

Hi Peter,

Appreciate the insights. My geyser is only set to go on in the morning. I have the timer for the element to start around 5am and to achieve about 65deg. Im the first to go in the shower and around 6pm the temp is near 65. After about a 5 minute shower, the temp drops to 33 which allows for another shower, maybe 2 but we pushing it. Sometimes we switch on the geyser after im finished if both my son and wife needs to use it immediately after. Other than that, the element is off for the day, even in winter. No showers in the evening. Still not convinced the geyser is causing this. My new bill arrived for June and its a shocking 3k for electricity. We have a gas stove and gas heater so not contributing to the usage. If you say the pump is low usage, then the municipality is charging me incorrectly.

Hi Vish999

Is the bill only for electricity, or is it the whole bill?

There is a way to check your electricity usage. You would need to install a CT (current transformer) on the live wire of the 60A isolation switch in your DB or a Meter fitted in your DB.

Many devices come with a CT, and that can be connected to the web. With this, you can monitor your electricity usage. compared to your bill. Just remember, the bill might not cover the entire month from the 1st to the end.

If you leave the element off for most of the day and at night, it can take up to 3 hours to heat a geyser in Winter to 65 degrees in the morning.

The cost would be about 3KW X 3HR X 30 Days X R4/Unit = R1080.00 a month, including VAT, only for the geyser element if you only heat for 3 hours a day.

It will cost you about R80.00 a month if you boil your kettle (5 minutes) 4 times a day. 0.083 X 4 X 30 X 2KW X R4/unit

If you have an electric oven and use it, it will also contribute to the electricity usage.

The 12VDC 60W solar pump. If on for 8 hours a day. 8 X .06Kw X 30 days X R4/unit=R57.60 a month.

Edited July 2Jul 2 by Peter Topp

9 hours ago, Peter Topp said:

Hi Vish999

Is the bill only for electricity, or is it the whole bill?

There is a way to check your electricity usage. You would need to install a CT (current transformer) on the live wire of the 60A isolation switch in your DB or a Meter fitted in your DB.

Many devices come with a CT, and that can be connected to the web. With this, you can monitor your electricity usage. compared to your bill. Just remember, the bill might not cover the entire month from the 1st to the end.

If you leave the element off for most of the day and at night, it can take up to 3 hours to heat a geyser in Winter to 65 degrees in the morning.

The cost would be about 3KW X 3HR X 30 Days X R4/Unit = R1080.00 a month, including VAT, only for the geyser element if you only heat for 3 hours a day.

It will cost you about R80.00 a month if you boil your kettle (5 minutes) 4 times a day. 0.083 X 4 X 30 X 2KW X R4/unit

If you have an electric oven and use it, it will also contribute to the electricity usage.

The 12VDC 60W solar pump. If on for 8 hours a day. 8 X .06Kw X 30 days X R4/unit=R57.60 a month.

This really helps Peter!! I will investigate the CT option. Will make sense in the long run anyway. Thanks again and take care.