Water heater as buffer tank.. how to clean it out if it has no drain valve ?

Dave Carpentier

Looking at this Bradford heater to be used as a buffer tank for our new boiler.
This is the "T" (tall) version of the 12 gallon single element.
(There are 3 ports on top not shown, 2 alternative in/out and an anode port)

I would connect it like this..



The question is.. how would I go about rinsing trash out of the bottom of the buffer seasonally ?
The tank ports are 3/4". Would I put a 3/4 or 1" tee and a ball valve between the tee and the "large pipe" ?

Or.. because this tank has no drain port, can I assume that the port is right at the bottom of the tank, and any trash will just flow towards my boiler during use.. so I would be better off installing a dirt separator of some type between the Large Pipe and the UPS15-42 ?

Larry Weingarten

Hi, It would be some work, but doesn't really involve any plumbing... Drain the tank and remove the element. Make a "wand" using a 3/4" piece of PVC pipe hooked up to a shop vac to pull out any sediment that's sitting there. You can add a 45 near the end of the PVC to be able to reach all areas of the bottom better. The wand can also be made of copper which will fit more easily through the element port.

Yours, Larry

mattmia2

Tee and a drain at the lowest port. If it is a closed system there really shouldn't be much in there. If you really needed to flush it you might think about how to route water in another port and out the bottom when flushing.

STEVEusaPA

Larry Weingarten said:

Hi, It would be some work, but doesn't really involve any plumbing... Drain the tank and remove the element. Make a "wand" using a 3/4" piece of PVC pipe hooked up to a shop vac to pull out any sediment that's sitting there. You can add a 45 near the end of the PVC to be able to reach all areas of the bottom better. The wand can also be made of copper which will fit more easily through the element port.

Yours, Larry

You should write the definitive book on water heaters one day, and put that in there.
Oh wait, you did. I bought it years ago and it's the only one I ever needed.

https://heatinghelp.com/store/detail/the-water-heater-workbook-a-hands-on-guide-to-water-heaters

hot_rod

since it should be a closed loop hydronic system, really no need to flush it yearly, or at all. In fact you don't want to add fresh water once it is up and running and air free.

A DirtMag on the return to the boiler is a good addition to protect any ECM circs. And an air sep at the supply out of the boiler.

Dave Carpentier

My first time looking thru the Dirtmag instructions.. that's a sweet little device.
If I put that on the vertical just under my UPS circulator, should I keep it at least 12" below ?

Three airvents then, like this ?

hot_rod

A Discal at the hot supply right at the boiler

An auto air vent on the AH or whatever is the high point in the system. Maybe an auto vent on the buffer if it has a top port.

On the AH use a float type vent with a hydroscopic cap for double protection 

mattmia2

There is a combination dirtmag discal too. the circulator unless i'm missing somethin should be on the outlet of the boiler and the air eliminator should be between the boiler and circulator where the water is hotest and lowest pressure.

Dave Carpentier

@mattmia2 - The Lochinvar IOM for this model (Epic) shows pumping towards the inlet in the diagrams.
Im not sure why some manuf's show it one way of thinking, and others the opposite ?

mattmia2

Because 75 years ago they thought the hot water would damage the circulator? Maybe someone else has a better answer but that section of the system looks like it is isolated so pumping out of the boiler would have the same effect on the rest of the system and make air elimination more effective(although the tank also does a good job of air elimination if you can get a vent on it).

hot_rod

The small amount of delta P added by pumping into the boiler assured positive pressure and could prevent flashing at the hot surface walls. The water tube style like Sermerta heat exchangers have high pressure drop and always showed pumping into the boiler, still away from the PONPC, of course