DHW hook up

DHW hook up

PostBy: mariohotshot On: Fri Dec 13, 2013 12:40 am

I have my DHW connected to my coal stove. The water comes out of the bottom of the tank into the coal stove and returns to the top of the water tank. This is the way the manufacturer recommends the installation.
This works great while no one is using any water in the home. After circulating many times, the tank warms up.The problem is when someone uses the shower, make up water enters the bottom of the tank. This cold water goes into the coal stove (it only has one loop) so it doesn't have enough time to warm up. When it returns to the top of the tank, I'm actually dumping cold water on hot water and I can hear my wife screaming in the shower!
Is there a better way to do this? Maybe routing it in the opposite direction? (I have a circulating pump in line).
Thanks in advance.
Stove/Furnace Make: keystoker
Stove/Furnace Model: 105

Re: DHW hook up

PostBy: blrman07 On: Fri Dec 13, 2013 6:04 am

Welcome to the confusing land of heating your DHW with a coal stove. There are a lot of variables. Things that seem to look good on paper turn out to be a waste of pipe and time.

I have a small Bucket a Day (BAD) coil fired water heater that supplies all our DHW. I piped it to thermosyphon to an old gas water heater that I pulled the burner out of. I am not using a pump. Cold water in goes to a T that I installed at the tank drain tap at the very bottom of the tank. Just up from that was another tap that I piped to the BAD inlet. The hot water from the BAD goes into a T that I put in the pressure relief tapping. Before someone goes nuts, yes I reinstalled the pressure relief valve in the T. The tank and the BAD are properly protected. The water out was piped as normal and the water inlet was capped.

If your feeding the inlet water directly into the line to the coil than it doesn't have enough time to heat up all the water that is being used. It sounds like your getting the water in the tank hot while it sits but on usage the inlet water is passing through the coil too fast thereby causing the wife scream sound that you hear.

If you can post a photo of your setup that will help. It's all a matter of getting the piping in the right spots. The trick is to use the hot water from the tank, not the outlet from the coil.

Hot water from tank = no wife scream sounds. :D
Hot water from coil = wife scream sounds :o

Rev. Larry
Hand Fed Coal Boiler: Bucket a Day
Hand Fed Coal Stove: Vigilant Casting 2310
Coal Size/Type: Pea/Nut/Wood in the VC and anything that will fit in the Bucket a Day. It's not fussy.

Re: DHW hook up

PostBy: Lightning On: Fri Dec 13, 2013 7:28 am

If your tank is positioned properly, cutting out the circulation pump that's in line with the coil should fix the problem. Yer right. The pump is taking cold water to the top of the tank. I use a temper tank between my coil and electric hot water tank. Here's some good reading

Hot Water Coil Project
Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size