Solar war water heater issues

[raro]

I have  solar heater on the rooftop and never really had issues with it. Last year I cleaned it for the first time when I noticed that it didn't really heat up the water anymore. 

 

This year, I cleaned it twice only this month (yeah, a bit dirty, but not much) and efficiency improves. But not as good as it used to be. Any ideas what else the problem could be? 

[Lamkyong]

my guess would be  connection problem ie corrosion in the electrical  system  this is from my experience with my solar system  easy way sheck (multi meter)the solar output first   or input

 

your choice  

[raro]

nothing electric here, apart from the pump. It's just water running through the heater element and a storage tank on the roof. No photo-voltaic. 

[worgeordie]

What kind of panels does it have ?,maybe the pipes inside are partially blocked,

I had  a SolaHart  system fitted 27 years ago,when we built the house,and it worked,

without fault until about 2 years ago when the tank developed a small leak,nothing

major,and collected the water off the roof to water the plants,but I did contact 

Solahart,to see if could buy just a new tank, no they only sell complete system,

now the price was 160,000 THB,when i bought original system was 40,000 THB,

so that definitely paid for itself.

 

So decided to put up with the small leak,instead of spending 160,000 THB,which

I would not live long enough,to see it pay for itself, so 2 years put up with the leak,

then one day the water in our area was going to be off for 12 hours, so turned on

the pump,to get water from the tank, and it happened, the extra pressure just blew

a big hole in the solar tank,with water gushing out, so now i was going to have to buy 

a new system, so i googled Solahart Chiang Mai, and the first listing was for Chiang Mai

Solar,went to website and found they had been operating in Chiang Mai for quite a while,

so contacted them,its owned by a German man, I explained my problem,and asked could

he supply a tank, OK no problem, in 3 days they had it installed,cost 32,000 Thb,the tank

is imported from Greece, so have hot water again,at a reasonable price

 

Its  a two story house and it took 7 people to get the old tank off the roof,I suspect it

must have had a lot of sludge in it,built up over the years.no need for a pump,unless

the mains water goes off,no no moving parts,no electricity ,would recommend  Solar

water heating, especially if building a new house,where you can have hot water pipes

run to sinks,showers and bath if you have one,there are cheaper ones than Solahart,

say 50-60K THB,and electricity prices are not going to get cheaper only more expensive.

even on dull days with a little sun the water gets hot,on hot days it scalding.

 

regards worgeordie

[Lamkyong]

1 hour ago, raro said:

nothing electric here, apart from the pump. It's just water running through the heater element and a storage tank on the roof. No photo-voltaic. 

oh ok sorry no help

[raro]

6 minutes ago, Lamkyong said:

oh ok sorry no help

 

 

no problem

 

@worgeordie: any chance to get the sludge out? the system is now about ten years old. And yes, I can only highly recommend solar warm water. Works on most days of the year, except when its heavy rain for a couple of days. Other than that, up to boiling hot!

[raro]

Update:

 

There is a company that does solar stuff nearby, went there. Chinese owned, no English. But very friendly guy and he had a Chinese buddy who spoke English and translated over the phone.

 

So the guy comes to my house, opens some plug on the bottom of the solar panel and lots of dirty water came shooting out. He said, might be that just dirt clogged it up and should wait for a couple of days. And a couple of days later, still no warm water.

 

A new system was quoted @ 55,000 Baht. Worgeordie apparently got a system @ 32,000. Now....what different systems are out there, what is the best bang for the buck?

[raro]

did some more research on the topic. Seems like I have a passive flat plate system. My understanding is, this is very straightforward without any wear parts. A plate collector attached to a tank and that's it. No heatexchanger pipes, no pumps, nothing that could really break.

 

I flushed the system again , a bit of dirty water came out but mostly clear water - but just luke warm.

 

My research revealed really nothing as potential problem other than the a potential clogging due to hard water or dirty water. Any dirt I believe has been flushed out now and it is rather fine silt than particles large enough to clog up the system. Hard water? Maybe. Infusing vinegar into the system? Would that work or lead to other problems like corrosion?

[Pacificperson]

Check with your Chinese vendor to see if he does internal cleanings (descaling). I believe that it maybe a part of the routine maintenance requirements. White vinegar 1:1 with water sitting for several hours might work.

[raro]

Didn't hear back from them, I take this as a no. Asked a German guy who is peddling solar heaters but he is only doing pipe heaters, not plate heaters - for this very reason. Clogging and the problems associated with it.

 

Anyone knows of a company that could do this service, preferably based in Pattaya?

 

In the meantime, the water temperature gotten better again, but still not as hot as it used to be.

[madmax2]

I do not know about modern solar HWS but a long time ago (about 30 years) i had a water heating problem which i fixed by giving the solar heating panel a fresh coat of flat black paint which improved the heat absorption 

[RichCor]

Can you take a photo of your installation?

 

The simplest of systems for water heating is to throw a spool of black hose up on a roof.  Installations tend to get a bit fancy from there.

 

On 1/7/2017 at 6:53 PM, raro said:

[...]

Seems like I have a passive flat plate system. My understanding is, this is very straightforward without any wear parts. A plate collector attached to a tank and that's it. No heat-exchanger pipes, no pumps, nothing that could really break.

 

 

How hot is the plate collector getting while in full sun, and is the tank insulated (so it retains the heat it gathered from the plate collector the day before).

 

While the system's temperature can be influenced be the cooler winter incoming water temperature, the water already in the tank should have retained a lot of it's temperature increase form the day before. 

 

As other posters have alluded to, how clean, and freshly black,  is your plate collector?  Are there any bypass valves on the system that might have been left open, or partially open?

[Hereinthailand]

I think your collector plate has a layer of scale built up in it from the dirt and scum you flushed out preventing heat transfer. why not cap it off and fill with some weak pool cleaning acid like muriatic acid and let it sit for awhile then flush it with water. Its just a radiator after all.

[raro]

Yep, that's also what I suspect. The issue here is... How to get that stuff into the system? Would need someone to get on the roof and find this out. I won't climb up there as it is rather steep and I don't have any safety gear to do this safely.

So the question is...do we know of anyone who could do that job?

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