Draining sediment from my indirect fire tank

rob51

Hi all,
I have an indirect fire hot water tank.  The loop to heat this tank is heated from my boiler.  I would like to drain the sediment out of the tank (if there is any). I looked at the directions, but it was not very specific.  It just said to drain a few quarts and to be careful because the water is hot. 

1.). Should I shut down the boiler before doing this so the water in the tank will cool?
2.) should I shut off the ball valve where the water enters the tank before I open the spigot to drain it? 

3.) is there an anode or something that collects impurities in this tank and can I realistically replace?
If someone could give me a step by step on what I should do, I would appreciate it. Thanks again.  This is a wonderful community.  

P.S.  I have enclosed some pictures. 

STEVEusaPA

Probably no anode with stainless steel.
Here's a great resource for all things water heaters, applies to some indirects too.
https://heatinghelp.com/store/detail/the-water-heater-workbook-a-hands-on-guide-to-water-heaters

rob51

I was reading an earlier thread saying it’s not necessary to drain sediment from an indirect fire because of where the heat transfer occurs.  Is this true?

hot_rod

Ever had your water tested?the hardness and TDS has a lot to do with thebuild up in any tank that is heater. High temperature coils from the boiler water can also scale.

It takes some pressure and turbulence to flush heavy sediment. Just opening a drain may not do much.

kevink1955

Mine is piped the same way, cold inlet at the drain valve. At least you have another fitting with a valve on the other side down low. You will never get any sediment out of the valve on the inlet, all the water you get will be coming from the cold supply.

If the fitting on the other side at the bottom on the other side is not the boiler coil try it and see what comes out

I am in the same boat with my Bradford indirect, the only way I can get a good back flush is to shut the cold supply off to the tank and back feed the hot side by putting a jumper hose from cold to hot at the washing machine connection

Larry Weingarten

Hi, I looked over the tank schematic and flushing out sediment will be some work. I'd drain it down, replace the boiler drain with a full port ball valve, and remove the thermostat so, with some copper tubing you can aim a jet of water at the coil, with the hopes that sediment will be flushed off the coil and out the drain. Another thought is to find a borescope and find a way to have a look inside of the tank so you can see both the coil and tank bottom first. I imagine you would need to remove the thermostat to do this also. I wonder if an HTP engineer might know something about how their coils scale up in different waters?

Yours, Larry

ps. Thanks @STEVEusaPA

hot_rod

There was a product called a muck vac to clean out scaled water heaters. It was about the only way to get ALL the sediment out IMO.

With Indirects, as the coils scale on the outside it takes gallons of acid in the tank to descale them.

There were some tricks to shock the coils, empty the tank, get the coil hot and hit it with cold water. I’m not convinced it did much good.

Smooth coils tend to do better than finned coils in hard water.

Softening helps a lot. Or maybe some of the magnetic or TAC type treatment devices that allegedly keep minerals in suspension.

The two options are remove the minerals before the water enters the tank, or deal with them inside.

A few thousands of an inch of mineral build up really hammers heat exchange. Being a slow gradual decline it often goes unnoticed and homeowners unknowingly adjust their DHW habits to the lower production is my experience.

Larry Weingarten

Thanks @hot_rod for remembering the Muck Vac. I developed it and serviced thousands of tanks with the one I kept.

About stainless and softening, potassium chloride is an alternative to normal salt softening which is not as hard on the stainless as sodium. Might be worth looking into. A possible benefit is that softened water is claimed to remove scale build-up over time. If so, you won't need to dig into your tank.

Yours, Larry