Leaving evacuated tubes dry for 5 days

[Edlk]

I have a 10 panel thermal evacuated tube pressurized system
I have a hea t dump which I drain for the winter months to avoid freezing
I am going out of town for a week and having my son watch the house.
I thinking about draining the system so he would not have to deal with my back up generator system in the vent of a power outage and loss of circulation resulting in a pressure blow off.

Will leaving the system dry for 5 days damage the tubes or manifolds in any way.

[Mike90250]

I'm not sure, but bright sun, with no cooling, can get evacuated tubes way hot. Covered with a tarp would keep the heat down. What does the instruction manual say ?

[Naptown]

If in doubt the safest thing is to cover them. No production but also no damage to the system either

[Art VanDelay]

If you have a large enough expansion tank, it will "steamback"

Just google "steamback solar design" and you can find out if you have enough room for expansion, and if the PRV is at a high enough pressure. This is quite common in Europe and is the lazy man's way to deal with your problem. You can also recycle the components of your power wasting dump system. Cu is worth $$.

[LucMan]

I have a 10 panel thermal evacuated tube pressurized system
I have a hea t dump which I drain for the winter months to avoid freezing
I am going out of town for a week and having my son watch the house.
I thinking about draining the system so he would not have to deal with my back up generator system in the vent of a power outage and loss of circulation resulting in a pressure blow off.

Will leaving the system dry for 5 days damage the tubes or manifolds in any way.

Is there glycol in the system?

[sunno]

In my opinion not very safe, I would cover them...

[mtmtntop]

a different solution

i know you have been gone and come back quite a while ago, but i can offer a different solution which i have in place with a 75 tube array. I have a bypass loop that contains a 12 v pump that is connected to a 40 pv panel when the power goes off via an ice cube relay. This pump, and a zone valve that only opens when the power goes off, moves the glycol into a pex line i have buried under my deck to just dump the heat. this setup holds my array at about 145 degrees on a bright sunny day with snow on the ground. when the power comes back on, it automatically closes this loop and disconnects the pv panel from the 12 v pump, the emergency heat dump valve closes and all is well. even i was amazed at how good it worked.