Coal Fired Hot Water FINALLY

Sting · Post by **Sting** » Wed. Aug. 19, 2009 12:33 pm

The tempering tank I use -- is simply the 40 gallon NG water heater that I use in the summer months for DHW production. A cast off electric water heater would be a better choice if you can find one that was taken out for reasons other than corrosion.

I use a tempering tank because my boiler DHW coil is not up to the task of producing enough GPM - When I use it gently to temper the cold side water that I introduce to the thermo reacting valve - it provides sufficient volume on the hot side, to bring the supply to code set temperature for significantly more use at the desired GPM output.

This month I installed a used working 50 gallon electric DHW heater before and in series with a 4O NG fired tank to provide a couple kids with enough water to fill their big bubble tub. I turned the resistance heaters down to about 105 and wired a used magnetic switch to turn the appliance on and off remotely-- They simply plan to use the tub -- heat the temper tank for a few hours - and turn it off before filling the tub.

All from used and cheep parts

coal berner · Post by **coal berner** » Wed. Aug. 19, 2009 8:35 pm

billw wrote:Here's been my experience so far this summer.
I'm running at 3 teeth which is 7.5 lb per hour. The aquastat settings are lo 140, high 180. The boiler is pretty steady at 160.
The timer is running the stoker 5 minutes an hour. Anything less and I get an outfire, especially on hot, humid days. Total coal use for four months, June to September should be approx 1,800 lb. I rounded up to 1 ton because I'm sure on Saturdays when the clothes are washed the stoker is coming on more than just the timer but not positive how long. I paid 160 a ton last year. So total cost is 160 for four months or 40 a month. The other 8 months there should be no extra run time for hot water because it will be on for heat.

I'm saving 25 a month in the summer (4 months) and 65 a month during heating season (8 months) for a total of 620 a year.

Total cost of install was approx 450-500. Payback time is less than a year. It took me a couple of days to re-plumb the hot water system. Mostly because the new water heater is at the opposite end of the house.

Maintainability is easy. I'm getting a full ashpan every 9 - 10 days. I started taking it out every Sunday because sometimes I forgot about doing it so I put myself on a schedule. It's easier than cleaning up a mess. I'll have to clean the boiler one more time a year but that's no biggie. I plan on cleaning it at the end of September and again in May.

The only drawback is the basement gets hot now. It used to be cool in the summer, now I'm leaving the windows open. Maybe next summer I'll install a temp controlled fan to keep the basement cooler and maybe insulation on the boiler.

ADDED:
The mixing valve I bought doesn't have degrees on it, just hotter/colder. I should have looked around more before I bought it. When I first started it up I had it on hot. The water in the sink was steaming. I have it set to where it is comfortable but I would have liked to be able to set it at 125 degrees. Oh well, maybe next time.

Bill if you put a bigger spread on your aquastat you can turn down your timer to 2 to 3 minutes a hr what happends in this warmer weather is your aquastat is overriding your timmer the boiler water is holding the temp more so the
aquastat will not leave the timmer kick on because the boiler temp is at the high limit. No timmer kick on No Fire .
Try 150 low and 200 high and turn down your timer to either 2 or 3 minutes a hr. keep the your diff at 10 or 15 on your aquastat.

e.alleg · Post by **e.alleg** » Mon. Sep. 07, 2009 3:03 am

You are also saving money on stove pipe. With the DHW going your boiler is hot 24/7/365 days a year and your stove pipes will last 10x as long as if you shut down every summer. That is average estimate of $200 x 10 = $2000 savings in stack pipes over the years.

Post by **coaledsweat** » Mon. Sep. 07, 2009 8:36 am

e.alleg wrote:You are also saving money on stove pipe.

Not just stovepipe, it will add many years of service to the appliance too.

coalpower · Post by **coalpower** » Sat. Sep. 26, 2009 11:04 pm

JB Sparks wrote:
coalpower wrote:in the process of building a hot water absorption chiller to cool our house instead of A/C.
I would be interested in knowing how that works. Four A/C's running in this hot weather is going to make for a big electric bill this month.

I know that they have some large units on the market, But I want to build a resedential unit and maybe market it with a outdoor furnace co. not too far from me. So I don't want to tell too much info just yet. Sorry

leowis1 · Post by **leowis1** » Tue. Oct. 06, 2009 8:52 pm

I had alot of challenges getting my DHW working right. I installed/plumbed everything. During the 1st winter when the t-stat called for heat and you were in the shower, you got cold/luke warm water on you. It sucked! Then somebody on these boards gave me a great idea. I plumbed the hot water exit pipe from the DHW in the 520 into the NG 50gallon hot water heater (into the cold side). THEN I installed a T onto the cold water pipe going into the cold water of the 520. I soldered a hose bib on the one side of the T and connected a hose from there into the water drainage of the NG hot water heater. Make sense? So what happens here is that by gravity, I am banking all the unused hot water from the boiler into the NG hot water heater. The hose drainage is acting as an overflow that pushes the cold water back into the boiler.

So now when I'm in the shower and the t-stat calls for heat, my hot water supply is coming from the NG hot water heater and I get a nice even hot water shower!

I can tell you that in Oct/Nov and December I would have the shower valve almost on cold to get a nice shower because the water was soo hot. The in Jan and Feb the valve was almost on full hot to get the same temperture. This is because the boiler was always sending the hot water into the radiators and there was hardly any window to let the gravity method replenish the hot water in the NG tank.

I'm very happy with the setup. In the summer, I turn off the coal and use NG hot water. I don't have to touch anything.

Sting · Post by **Sting** » Tue. Oct. 06, 2009 9:29 pm

Install a thermal limiting mix valve before you hurt yourself -- one of your family 00 - or a guest that is unaware of you contraption danger.

http://www.caleffi.us/en_US/caleffi/Details/News/ ... /01080.pdf

Water out to the tap should NEVER exceed 120 degrees.

http://contractormag.com/plumbing/cm_column_168/

http://www.psdmagazine.com/ASPE_memberpdf/2007030 ... ingOut.pdf

Post by **stoker-man** » Wed. Oct. 07, 2009 6:11 am

I've heard the mixing valves don't last long. What has been your experience with them? Anybody?

Pa Dealer · Post by **Pa Dealer** » Wed. Oct. 07, 2009 7:18 am

Mixing valves work for a while , but seem to stick in position and not adjust to boiler temp. changes.

R

Sting · Post by **Sting** » Wed. Oct. 07, 2009 8:07 am

And they are as easy to rebuild as replacing the cartridge in your sink faucet.

Yes its an expense, Yes I hat to do that -- how often??? depends on your water conditions. But think about the alternative for JUST a moment --

Cheese and Rice -- Pink body parts cannot be replaced as easily

Post by **coaledsweat** » Wed. Oct. 07, 2009 8:17 am

Pa Dealer wrote:Mixing valves work for a while , but seem to stick in position and not adjust to boiler temp. changes.

It's worse if you have well water. The harder the water, the quicker they will die on you.

Sting, if your body is pink, you are getting too much CO!

Yanche · Post by **Yanche** » Wed. Oct. 07, 2009 9:46 am

I had a mixing valve setup with my oil boiler internal domestic coil years ago. With my acid well water, ph = 5.7, I could never get it to work. I'll take it apart and there was lots of acid etching and pitting. That's one reason I went to a stainless steel tank indirect hot water heater. No problems now. It's plumbed with 316 stainless pipe fittings and CPVC plastic. Temperature is well controlled by the thermostat bulb in the tank and the hot/cold water mixing action in the tank. An expensive solution but it works well. For me it's less expensive than the constant replacement of anode rods and glass lined water heater tanks.

Post by **stoker-man** » Wed. Oct. 07, 2009 11:21 am

Did you install an acid neutralizer for 5.7PH water? I have one and the water is fine.

If the mixing valves are rebuildable, we don't have any kits. What type is rebuildable and where to get parts?