Evac tube solar water system not working

[sanramon]

Baku - I must say I am not familiar with copper pipe. In Canada we use PEX with crimped fasteners. Here in Costa Rica we use CPVC for hot water, with CPVC glue. But - I cannot imagine that a solar water heater is going to damage your copper pipes any more than a conventional gas or electric system.. Your water must be clean, I assume it is drinking water, so there should be no corrosive effect. I would say a bad solder joint could fail due to cycling hot and cold over many years - just like an electronic circuit solder junction can fail. Stuff breaks!

A question for you - you emptied your evacuated tubes so must know what type they are. Was there anything in the tube - U-tube, or copper heat conducting pipe? Since it looks like you have a non pressurized storage tank, I cannot imagine you have either of those types. So I would guess it is simply a hollow, double walled glass tube? I have that system here, and it is quite cheap but very efficient, possibly more so due to the tropical sun shine. Just curious.

[LucMan]

Expansion of the water as it is heated can be a big problem, relieving pressure through the P&T valve, or blowing fittings apart at the solder joints or mechanical connections.
A hydronic expansion tank will be required if there is a check valve in the incoming cold water main line.

[sanramon]

Interesting point LucMan. Strangely my system has been in for 4 years, doesn't have a P&T valve in the serpentine and I haven't had a problem - yet. Perhaps because we use CPVC pipe rather than copper. Maybe it is more forgiving of water expansion than solid copper pipe. Your thoughts? Of course our storage tank, which is non pressurized has the fill/overflow tank.

I will have to ask the vendor here his thoughts on this.

[baku]

Sanramon, yes, our system is the hollow, double walled glass tube version. Nothing else required with our tropical weather.

LucMan, I looked online whether thermal expansion could cause solder joints to break in water systems. In principle, it appears it can http://www.copper.org/applications/p...explained.html

I will take this into consideration on how we proceed. The handyman bailed on us today but is supposed to come tomorrow. Curious to know where on the pipe the leak is occurring. Hopefully we can find it. If we find it and it is on a solder joint, it might be best to re-route the pipe outside the house instead of fixing it and closing up the wall again.

[LucMan]

You were lucky for 4 years without a leak occuring.
No P&T valve, you should add 1 to the outlet of your HX along with a small expansion tank designed for domestic water.
Do your self a favor and hire a qualified professional to perform the repairs and updates.

[sanramon]

Thanks for the counsel LucMan. I will look into installing an expansion tank. However, remember this is Costa Rica! The system was installed by the agents plumber! Along with no P&T valve or expansion tank, he also installed the tank off level, such that the boiling expanding water jetted out the storage tank vent pipe. See my photo 2 of post #10. I made that diagram for the agent, who had the installer come back and remount the tank to prevent the problem - then he fired the installer!

After our large earthquake of 2014, our tank nearly collapsed on the roof. I had to visit the now-fired plumber to get some bracing material (unused brackets), then straighten the tank legs and mount braces left right and centre. The 'plumber' said "we've never had that problem before".

There are no "qualified professional" people here to do the work. I put in my own water storage, pressure, filtration system, and will be doing this work also.

But thanks again for the advice. A project - before my luck runs out!

[baku]

Thanks Lucman. I'm pretty much on the same boat as Sanramon, hard to get qualified professionals to get it done (my first post here explains that we had already brought two 'repairmen' to fix the problem. After $220 total the problem remained). In our case though, our main priority should be avoiding the joints to break, which are harder to fix than repairs directly related to the solar water system