Any chance for thermal stress with filling cold water?

sunlight33

I am going to drain my indirect tank for cleaning then fill it up with water at 50F (city water), so the tank will go from 120F to 50 then back to 120 in a few hours, there shouldn't be any concern for thermal stress right?

EBEBRATT-Ed

No, you will be fine

Larry Weingarten

Hi, Almost certainly not. Just think what happens when filling a tub. Still, is it a stainless, glass lined, or stone lined tank? I’d expect that stone lined would be at most risk from thermal shock because of the mass of the lining, but even then, it’s minimal.

Yours, Larry
Ps, You could let it sit for an hour to adjust to room temperature before flushing with cold water

sunlight33

Yes, I will also soak the tank with Qwik Descaler.

sunlight33

I flushed the tank yesterday, replaced anode rod and the drain valve (old one was leaking). I noticed there are some debris at the bottom of the tank (small rocks and sand) that cannot be removed by the drain valve. The tank can only be serviced from the top from an 8'' opening. I figure the debris won't do any harm, but if I want to get them out is vacuum the only option?

HomerJSmith

If you drain the indirect, be sure and open up some hot water faucet in the house unless you have a vacuum break on the indirect. You could crush the thin wall of the tank as a vacuum build up as the water leaves the tank.

sunlight33

I see, I left the pressure relief valve open so water could leave the tank. If I don't do that or open any hot water faucet the water won't even come out a bit from the tank.