Solar thermal system dripping from overflow

bobbyD1978

Anyone any idea why my thermal solar system is dripping from the overflow? It used to happen the odd time but now it's all day. Very small drops but still constant. Had the system serviced and allegedly all OK.

The central heating system is turned off at present and they're was no drop while the thermal system was out of action due to no pressure.

dathi

either the pressure release valve (prv) is broken or the pressure vessel has lost the pressure and as the system heats up it has no where to expand

bobbyD1978

I see. Thanks for the answer

John.G

There will/should be a pressure gauge close to the solar circ pump, what pressure is this showing when solar panel(s) cold, like now, and what is the pressure when hot, the PRV on these systems is set to 6.0bar.

With any system pressure, remove the valve cap on the expansion vessel air end and press in the (schrader, like a car tyre valve) valve pin with your nail or a screwdriver, if water comes out then expansion vessel diaphragm failure.

bobbyD1978

Thanks guys, I'm back up in the attic and I found all these valves. Couldn't find anything to stick a screwdriver in. Pressure seems fine and water is hot at 60 degrees but dripping as usual.

Beres the valves I found and FYI, I'm willing to pay anyone here that is local to swords. I'm not looking to cheap out and DIY it instead of paying a pro

dathi

your second photo is the prv valve for your cylinder is this where the water is dripping from ? or is it dripping from the solar fluid circuit there will be a prv valve near the pump station

the expansion vessel looks like the below again if you have a pressurised cylinder you will have two of theses one near the pump station for the solar fluid and one near the cylinder, it was this that we were asking you to check if there is air pressure in. you unscrew the black cap and there will be a valve like on the wheel of a car

https://www.screwfix.ie/p/flomasta-potable-expansion-vessel-18ltr/148KK?gad_source=1&gclid=CjwKCAjw6c63BhAiEiwAF0EH1HlfSfRv9egvO-7m6Le_g0ZtikpnSS9hlETSoSuLaM0kQC7p27xloBoCSlAQAvD_BwE&gclsrc=aw.ds

dathi

https://www.ebay.ie/itm/116127716760?chn=ps&var=416311902933&norover=1&mkevt=1&mkrid=5282-166454-587998-0&mkcid=2&itemid=416311902933_116127716760&targetid=2308550382662&device=c&mktype=pla&googleloc=1007872&poi=&campaignid=21085357813&mkgroupid=160523081500&rlsatarget=pla-2308550382662&abcId=&merchantid=697646556&gad_source=1&gclid=CjwKCAjw6c63BhAiEiwAF0EH1G6uucSkzts7tD25oHQDPdEgjn188brnZHPN1MiEWEwL_9ZBfHBVQRoCqV8QAvD_BwE

your solar pump station will look something like above and the trv is yellow in that example .and your first photo is your thermostatic mixing valve it takes very hot water from the cylinder and blends it with cold water reducing the temp to mid 40s to prevent you from scalding yourself

bobbyD1978

https://www.boards.ie/discussion/comment/122653006#Comment_122653006

thanks

the pressure near the expansion tank is at 30 and seems fine, holding steady.

The actual drip is from the overflow pipe outside. Or at least thats what I call it as its the exact same as my original overflow pipe. for some reason only two of my images uploaded. Theres two more now. One of the expansion tank and pressure and a second which has red circles showing the pipe that has the drip coming from it outside the house (it leads outside) and the second red is where we previously had a leak but it was fixed. The plumber said the previous leak was unconnected to the pressure issue which (fingers crossed) is fixed now

bobbyD1978

images

dathi

ok in your first picture the piece with the grey cap and the red prv is an automatic filling valve this takes mains water and keeps the circuit after it at a set pressure these regularly fail or are set too high which can cause the red prv to give up the ghost . automatic filling valves are not the best to have on a system because they hide leaks as they keep the system toped up . a filling loop is preferred. don't think i want to know how the two pipes over at the panda head are joined as it just seems to be shoved onto the copper pipe, the second picture looks like the expansion vessel for the solar loop that's going by the polystyrene box in back round, and it will be a separate circuit to the water in your hot water cylinder you should have a second expansion vessel for the hot water cylinder if its pressurised which it looks like as it has a prv valve and they work by having a rubber balloon filled with air on one side and water on the other and as the water heats it expands into the area taken up by the balloon when there is no pressure in the balloon the vessel fills up with water and has no where to expand into when hot. this is why we are asking you to check if there is any air in this vessel

bobbyD1978

Seems too much for a novice like me. I appreciate the replies but at this stage I think ill try and find a pro to check it

thanks

Latro

This is what you need to do. Check 2 min and 23 sec. If the water comes out the expansion vessel needs to be replaced.

The valve is sometimes under a plastic cap.

https://youtu.be/m1repkd1HHc?si=TUx2PvUpcpseQcf7&t=143

bobbyD1978

I found two tanks with those valves. The one in the wall, air and pressure stayed up. The second one on the ground water comes out. So that's failed is that correct?

bobbyD1978

First pic is the one that's in the ground and no air

dathi

picture 2 looks like the solar fluid circuit that's the fluid that flows through the solar collector on the roof and through the coil in your cylinder, basing that by the pump station that's partially seen behind the white expansion vessel and the 25 litre plastic drum that the prv has been piped to, also the grey polystyrene cover for the pump station is on the shelf behind it ,it should be covering the pump station. the blue cylinder in the back of the picture is that also an expansion vessel ? and is it this one that has no air or the one in picture no1 if there is water coming out of the air valve when you check it it means that the rubber gasket is torn and you will need to replace the vessel

bobbyD1978

Water is coming out of number 1. The white vessel on the ground

John.G

https://www.boards.ie/discussion/comment/122690047#Comment_122690047

There should be a pressure gauge on the (solar) pump station, check its reading, it should be ~ 2.0bar with solar syatem cold and ~ 2.5bar with hot system, the PRV lifts at 6.0bar.