Solar Tubes not heating water

dp639

Hi,

I've a problem with my solar tubes not heating the water. To start at the beginning - about a week ago I noticed the solar was switched off and looking through the display features on the control panel it had been off for 2 months, someone must have accidently switched off the switch as its beside other switches in the hot press - not sure if this has any relevance or not. I switched it on and everything seemed to crack into action so I didn't really look any further.

On Friday past a squealing noise was heard coming from the hot press, lucky I was in the next room so I switched it all of. I switched it off within 10 or 15 seconds and I think it was coming from the pump.

I loosened the bleed screw and a tiny bit of air came out and no fluid. So I reckoned maybe the pump was ceased, I took the bleed screw out and switched on the pump and could see it spinning.

Switched all of for the day as I had to leave and then on Saturday I added some air to the expansion vessel (it was 15psi, I topped it up to 30psi like the other vessels in the house). Switched the system on and could hear water circulating for while - loosened bleed screw until fluid dripped out and tightened it again.

Motorized valve seems to be working fine also.

At this point I thought all was good but returned after a while and the storage temperature did not go beyond 19 degrees. Pump gets very hot - is this normal?

Attached are pictures of display panel and gauges - does anything look odd/wrong?

Any ideas at all?

Everything switched off at the moment.

Thanks in advance!

John.G

Your system pressure at 1 bar is borderline low (right hand gauge on the pump station) and you probably have air trapped in the collector system as the tubes will have reached temperatures of + 200C, I would reduce the expansion vessel to 1.5bar (22psi) and then get someone to pump up the system to 2.5bar with solar fluid or possibly get it renewed, that will then give a few litres of reserve fluid in the expansion vessel.

dp639

thanks John - I'll get that done.

Tiger31

https://www.boards.ie/discussion/comment/120628123#Comment_120628123

Hi John. Can you recommend anyone Todo as you advise. I have a similar issue with my tube system.

dp639

I think there is a problem at the moment - I'm finding it hard to get a response from places to do this work - must be all too busy doing installations and not interested in servicing!

John.G

Unfortunately, no I don't know of any installers.

Re your system, assume pressure gauge was still reading 1bar when you pumped up the EV to 2bar (30psi)?

When the circ pump starts, does the flow meter register any flowrate.

Does the collector temperature rise even with pump off?

Have you collector's on two roofs?

What make/model of 3 way valve have you go?