Heat dump problem

Anthonyk2010

I have a rad in my garage attic which is used as a heat dump during the summer for my solar panel.

I had a look at it yesterday and noticed that the rad had cracked at two point where it is spot welded.

could i reweld it and how do i prevent this happening again.

Outkast_IRE

you prob could get it rewelded but id imagine it might be near the same price (unless you have a buddy whos a welder )to just replace it with a new rad.

Anthonyk2010

Outkast_IRE wrote: »

you prob could get it rewelded but id imagine it might be near the same price (unless you have a buddy whos a welder )to just replace it with a new rad.

I have a buddy who has all sorts of welders, but i wanted to throw it out there.

Outkast_IRE

Anthonyk2010 wrote: »

I have a buddy who has all sorts of welders, but i wanted to throw it out there.

Only thing to be careful of is your will need to refill and purge the system of air once you do it so you will need a proper filling station and the antifreeze added in correct amount.

quentingargan

Did your system have antifreeze in the first place? It is common (and perfectly alright) to use the controller antifreeze option - it pumps a small amount of water from the cylinder up to the panel when it falls below about 4 degrees.

However, the heat dump is uninsulated and will often be at a lower temperature than the panel, and is excluded from the circuit. Any system with a heat dump should be filled with antifreeze.

In relation to welding, bear in mind that the radiator will have to hold together under pressure of perhaps 3 Bar and the weld will also have to accommodate expansion and contraction of heating and cooling. It is also quite light steel. Personally I would use a new one in that situation - if it does leak, you will again have to refill and vent the system with antifreeze which is a bit of a hassle. But there is no reason other than all that not to try - you could pressure test it to 6 bar with water before wasting antifreeze.

By the way, one of the reasons for using a heat dump is that antifreeze gets degraded at high temperatures. Very few people test their antifreeze to see if it is still up to scratch. It will be interesting to see if there have been any panel failures after the recent frost. Worth having a peep at the pressure gauge to see if the pressure has dropped:o

Anthonyk2010

quentingargan wrote: »

Did your system have antifreeze in the first place? It is common (and perfectly alright) to use the controller antifreeze option - it pumps a small amount of water from the cylinder up to the panel when it falls below about 4 degrees.

However, the heat dump is uninsulated and will often be at a lower temperature than the panel, and is excluded from the circuit. Any system with a heat dump should be filled with antifreeze.

In relation to welding, bear in mind that the radiator will have to hold together under pressure of perhaps 3 Bar and the weld will also have to accommodate expansion and contraction of heating and cooling. It is also quite light steel. Personally I would use a new one in that situation - if it does leak, you will again have to refill and vent the system with antifreeze which is a bit of a hassle. But there is no reason other than all that not to try - you could pressure test it to 6 bar with water before wasting antifreeze.


By the way, one of the reasons for using a heat dump is that antifreeze gets degraded at high temperatures. Very few people test their antifreeze to see if it is still up to scratch. It will be interesting to see if there have been any panel failures after the recent frost. Worth having a peep at the pressure gauge to see if the pressure has dropped:o

No quentin i had no antifreeze in the system, i was using the antifreeze option on the controller like you menitioned above, never thought about the rad not being protected.

If i'am to put antifreeze in is there a fill valve i can get or do i have to install a pump station?

Is it a standard antifreeze like what is used in a car or is there a solar antifreeze?

quentingargan

Anthonyk2010 wrote: »

If i'am to put antifreeze in is there a fill valve i can get or do i have to install a pump station?

Is it a standard antifreeze like what is used in a car or is there a solar antifreeze?

Never use standard antifreeze. Ethylene glycol, as used in cars, is lethally toxic, and should there be any failure in the coil of the cylinder, it woould be dangerous. You should be able to get PROPYLENE glycol from solar installers or good hardware stores.

As regards filling, most installers have a special pump trolly used for flushing, filling, and de-gassing the system. DIY'ers sometimes fill the system using knapsack sprayers plumbed in temporarily with fluid pre-mixed. You can calculate the volume you need and pour this into the system by whatever means and then fill and pressurise from the mains if this is what you did in the past. I enclose a calculator for estimating the volume of concentrate antifreeze you need. You fill in the green boxes. You will have to add in for the radiator etc. as well... Results in yellow boxes are for possible low temperatures to be dealt with. Anyone's guess that bit after this winter!!

Q

Anthonyk2010

quentingargan wrote: »

Never use standard antifreeze. Ethylene glycol, as used in cars, is lethally toxic, and should there be any failure in the coil of the cylinder, it woould be dangerous. You should be able to get PROPYLENE glycol from solar installers or good hardware stores.

As regards filling, most installers have a special pump trolly used for flushing, filling, and de-gassing the system. DIY'ers sometimes fill the system using knapsack sprayers plumbed in temporarily with fluid pre-mixed. You can calculate the volume you need and pour this into the system by whatever means and then fill and pressurise from the mains if this is what you did in the past. I enclose a calculator for estimating the volume of concentrate antifreeze you need. You fill in the green boxes. You will have to add in for the radiator etc. as well... Results in yellow boxes are for possible low temperatures to be dealt with. Anyone's guess that bit after this winter!!

Q

Thanks for that Quentin, the calculator will be a great help.

Happy new year to you.