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Hi,
I'm new to this forum, but it looks like there are plenty of smart people out there who may be able to help.
I have a solar hot water system (evacuated tubes) and wetback (woodburner). It has been installed for 10 years and has worked well on the whole. The efficiency of the water heating from the sun/light seems to have reduced over time though. In the first year or two, the lower tank temperature at the controller would regularly read 80 to 90 in the summer. However this gradually dropped year by year until this last summer (our hottest/longest on record) when the temperature didn't really exceed the low 60's and mostly was in the 40's and 50's.
At the beginning of summer, I called out the plumber who initially identified the max temperature had been set to 60 on the controller. No idea how this happened, but changing it did help a little, although still the temperature only reached 70 degrees once for the rest of the summer. I have since called him out twice more but he says it's all fine and charges me a fortune for the pleasure. The tubes gave not gone white, nothing is broken and there are no leaks that I have found. The pump seems to be functioning correctly.
I'm starting to feel like a hysterical woman, so I thought I'd check out other opinions.
it's now winter, the wetback works fine as does the heating element, but there is just no solar gain from the system, even when the sun is out. I have taken to keeping a water usage/temperature/weather diary to prove I'm not going mad.
As an example, the back up element overnight took the top tank temperature to 60 as set and the controller which has the sensor at the base of the tank was reading 49 this morning at 8am. It was a beautiful day. Temperature around 16 to 17 degrees. Sunny until about 1pm then light, bright cloud.
With no hot water use during the day, just to test it, by 4pm when the sun went over the hills, (sets about 5-5.30) the tank had settled to 58 degrees and the controller read 55. As far as I can see, this is just the water settling in the tank and there was pretty much no solar gain at all.
To me this is not right. I used to have a temperature increase in cloudy weather, but now there's nothing even in the sun. Some of the tubes have discoloured, going from a dark blue to a blue green/paler colour. Is this indicative of the coating failing? Has anyone got any other suggestions?
Any advice is appreciated and I'll get more details on tech specs etc if needed.
I'm new to this forum, but it looks like there are plenty of smart people out there who may be able to help.
I have a solar hot water system (evacuated tubes) and wetback (woodburner). It has been installed for 10 years and has worked well on the whole. The efficiency of the water heating from the sun/light seems to have reduced over time though. In the first year or two, the lower tank temperature at the controller would regularly read 80 to 90 in the summer. However this gradually dropped year by year until this last summer (our hottest/longest on record) when the temperature didn't really exceed the low 60's and mostly was in the 40's and 50's.
At the beginning of summer, I called out the plumber who initially identified the max temperature had been set to 60 on the controller. No idea how this happened, but changing it did help a little, although still the temperature only reached 70 degrees once for the rest of the summer. I have since called him out twice more but he says it's all fine and charges me a fortune for the pleasure. The tubes gave not gone white, nothing is broken and there are no leaks that I have found. The pump seems to be functioning correctly.
I'm starting to feel like a hysterical woman, so I thought I'd check out other opinions.
it's now winter, the wetback works fine as does the heating element, but there is just no solar gain from the system, even when the sun is out. I have taken to keeping a water usage/temperature/weather diary to prove I'm not going mad.
As an example, the back up element overnight took the top tank temperature to 60 as set and the controller which has the sensor at the base of the tank was reading 49 this morning at 8am. It was a beautiful day. Temperature around 16 to 17 degrees. Sunny until about 1pm then light, bright cloud.
With no hot water use during the day, just to test it, by 4pm when the sun went over the hills, (sets about 5-5.30) the tank had settled to 58 degrees and the controller read 55. As far as I can see, this is just the water settling in the tank and there was pretty much no solar gain at all.
To me this is not right. I used to have a temperature increase in cloudy weather, but now there's nothing even in the sun. Some of the tubes have discoloured, going from a dark blue to a blue green/paler colour. Is this indicative of the coating failing? Has anyone got any other suggestions?
Any advice is appreciated and I'll get more details on tech specs etc if needed.
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