Kingspan Solar Hot Water in USA

draft_dodger

Hi, I purchased a home with a Kingspan Solar (Thermomax?) hot water system.
It seems that there is an airlock, or the fluid might have evaporated. (Maybe there is a leak?)
The system is not working and I'm wondering if its worth servicing at all.
Some of the local solar contractors I contacted said they only decommission these, they don't service.

hot_rod

Where are you located. How much DHW do you use?
Properly solar thermal can provide up to 50% of your DHW needs. Yes, they do need some attention an d maintenance.

Kingspan is certainly still around in many countries, a building facade company. I suspect the solar division is no longer around. The product had a 5 year warranty, 20 year if installed by a qualified dealer

Worth putting a pressure test on it, a reputable hydronic company should be able to at least pressure test them.
Then, depending if or where the leak is, it may be worth repairs. often times a relief valve pops and fluid is lost, it just needs a re-fill if that happened. Any signs of leaks around the pump module?

The biggest concern with evac tubes is they need a load, especially in summer months. If not the glycol over-heats and can be tough on piping components, pin holes, etc.

draft_dodger

I live in Baltimore, MD.
I'm not sure how much water we use, but the 80 gal tank (that has been running on the backup electric only) will sometimes run out (on a real busy day, approx. twice a month)

There is a pressure monitor on the system and it shows 2 bar/30 psi. No visible signs of leaks.

The reason I thought there was a leak was because the controller was showing the error "Volume flow fault. Check hydraulics. Air in system?" (I also didn't see any glycol in the vacuum tubes so thought it leaked out. I learned today that the fluid only passes in the manifold!)

So, I decided to plug the system back in today and just changed pump speed. It is showing a flow and seems to be doing something to bring some heat down into the water heater.

That seems to be working.

My next question is, I'm now getting an error about night circulation (check non-return valve). Is that normal if the incoming hot water in the tank is very cold and there is still some heat at the collector at night?

Thank you so much for your help.

Derheatmeister

When these systems are left stagnant for longer periods it can ruin the tubes.
The tubes becomes fogged up and it looks like something created Smoke inside the tube.
Can you post some pictures of the array..
You should have someone with Knowledge check the systems components and fluid..
Glycol does deteriorate when it is left to stagnant for longer periods..
Generally the PH drops and it becomes aggressive towards the piping,collectors(In your case the Manifold) Heat exchangers,Circulating pumps and other components
Which control do you have..Resol.Steca ?
Richard.

hot_rod

Sounds like you have a pump station with Grundfos vortex type sensors to get that info.

there are two check valves in the pump station, they prevent the hot tank from giving its heat back to the collector array. The temperature sensor on the array would sense that and throw the error code

Either a check is sticking and causing that, or you have a faulty sensor. Or a loose connection on the sensor wiring.

Feel the pipes going up to the collector at night, they should be room temperature. If they are warm your water heater may be warming the collector. An expensive heat dump.

The next check is the sensor, requires an Ohm meter. The manual will tell you what the resistance should be at different temperatures 

Sensor S1 is usually the one up on the collector and the one most prone to fail as it can see temperatures in excess of 400f on those tube arrays. Remove the two wires in S1 and check resistance.

Good that you have the heat pipe tubes they have a methanol mix in them and are freeze tolerant. But the header needs a glycol mix.
5 years or so is about time to flush glycol and replace it.

Derheatmeister

I still advise that you should have someone that understands solar thermal systems service it ! We are kinda guessing here...
If you post pictures of the system that would help!