Burning All Year Vs Electric DHW and Dehumidifier

Got away from burning with my VF3000 in summer because..
-Burned to much coal. Really would like to know how highlander does it at 7 to 10 lb a day.
-Made my basement to warm and in hot weather my living room above very uncomfortable.
-Loading coal & taking out ashes

My solution was buying a hybrid hot water heater, GE Geospring. Got it from Lowes on sale for 1300 - 10% coupon - tax rebate from fed - cash rebate from state of PA - Cash rebate from local elec co. PPl = $350 tax included. Cheaper than a regular water heater. Not sure what rebates are still valid. Prefeed through my DHW coil in winter (Only part I don't like it does put a little chill in the basement in winter) and in summer its DHW AND de-humidifier/AC. Keeps basement very pleasant in warm weather. Only problem I have is as I'm writing this its raining and 58 and while I'm summerizing my stoker its a bit chilly down here.

Hope this helps.

Highlander wrote:. The main drawback is the effort to maintain the boiler over the summer months, which involves emptying the ash about every 2 to 3 weeks, and the heat it adds to the basement.

I've been lucky to get 3 days without emptying ash pan. Might have to rethink using Casey Kassa Coal on next delivery.

-Burned to much coal. Really would like to know how highlander does it at 7 to 10 lb a day.

My boiler doesn't use the standard Harman timer, I designed a PLC based control system for it that runs the stoker only as much as needed to maintain 140 Degree water temperature. I also control the blower speed to limit the amount of air the blower pushes through the boiler, just enough to keep the fire happy, but not so much as to push heat up the chimney.

Highlander wrote:

-Burned to much coal. Really would like to know how highlander does it at 7 to 10 lb a day.

My boiler doesn't use the standard Harman timer, I designed a PLC based control system for it that runs the stoker only as much as needed to maintain 140 Degree water temperature. I also control the blower speed to limit the amount of air the blower pushes through the boiler, just enough to keep the fire happy, but not so much as to push heat up the chimney.

PC063087.JPG

PB083708.JPG

That is awesome.

So, if I run the inlet of the electric DHW tank through an EFM coil to heat the water up as it enters the tank, will this cause any negative effects to the stratification of the electric tank? As the water going into the bottom of the tank will most likely be hotter than the water at the top of the tank, causing the water to turn over within the electric tank?

Also, is a mixing valve recommended because the water going from the boiler to the DHW tank could be greater than 120 degrees?

If I have this setup and do decide to shut the boiler down for any reason, is it okay to have the cold well water going through the coil still? I am afraid of it causing condensation as the well water would cool down the boiler water quickly. I know it can be dangerous to have valves in any line that would restrict flow through this coil as pressure could build up in the coil and pipes if it was valved off and the boiler was operational.

Another option I have seen is to run a small bronze circulator to heat up the electric tank, with the control being an aquastat, so you get a tank temperature of 120 degrees. Using this method it seems you could avoid the mixing valve, but you have the pump and aquastat to add, so it seems just running the inlet of the electric tank through the EFM coil is much simpler.

Finally, are any brand of mixing valve more robust than the other...I don't see too much of a price difference but if one brand is easier to service or lasts longer than another brand that would be good info to have. The water is ran through a softener first so hopefully build-up will be minimized....but these same copper lines had hard water running through them for 30+ years.

For safety's sake, I would like to put a strap on aquastat on the coal auger to interrupt power to the stoker. I think any strap on type aquastat with a high limit circuit would work correct? Is there a different way to approach this same problem? I had a CO sensor go off a couple months back due to a fines bridge and my girlfriend has been a little spooked on the boiler since, even though I had it fixed and was back running without even losing the fire.

http://www.pexsupply.com/Honeywell-L6006C1018-Hig ... -1738000-p

It looks like forum member Pacowy (who I also got the boiler from) has some coils and I will be getting one off of him, so I should have the boiler back up and running sometime in the near future....and hopefully I don't have to shut it down for a long time other than cleanings.

Thanks,
Joe

JRDepew wrote:So, if I run the inlet of the electric DHW tank through an EFM coil to heat the water up as it enters the tank, will this cause any negative effects to the stratification of the electric tank?

It will quickly "right itself" when the water stops flowing. I have my brother's coil and electric water heater piped this way, and it works excellent.

JRDepew wrote:Also, is a mixing valve recommended because the water going from the boiler to the DHW tank could be greater than 120 degrees?

Yes, you should use one. You can mount it at the coil, or mount it after the electric water heater, that way you get the benefit regardless of if the coil is in service or not.

JRDepew wrote:If I have this setup and do decide to shut the boiler down for any reason, is it okay to have the cold well water going through the coil still?

No. You need to pipe a bypass around the coil. I know what you mean about having the coil valved off and then starting the boiler, but it is easy enough to have a start up check list hang next to the boiler. If you want more, pipe a pressure relief valve between the coil and isolation valves. Also put boiler drains in to allow future flushing or draining of the coil.

Here is a picture of the coil piping on my last install. Note that the "mixed water" pipe was not attached to the mixing valve yet. I like to use a brass nipple and tee to go from the coil fittings to the rest. You do NOT want to try and solder a fitting already screwed into the coil, it can melt the solder on the "water side" of the coil mounting plate and cause leaks. Don't ask me how I know either.
I later added ball valves and unions to make pulling the coil a simple task.

JRDepew wrote:Finally, are any brand of mixing valve more robust than the other.

I prefer the Honeywell units.

JRDepew wrote: Finally, are any brand of mixing valve more robust than the other...I don't see too much of a price difference but if one brand is easier to service or lasts longer than another brand that would be good info to have. Joe]

Something that gets overlooked often when installing Thermostatic Mixing Valves is...

Design Considerations

Heat Traps

All mixing valves used at the source of supply should be trapped. Trapping the valve helps reduce mineral deposits and premature component wear.
Heat traps help reduce convection loss also know as thermosiphoning, increasing system efficiency.

Stop Valves

All mixing valves should be installed with a means to isolate the valve for service and repair.

Some illustrations to help understand the concept:
http://www.esbe.eu/de/de-de/~/media/ESBE%20Public ... 20508.ashx

I have done heat traps with two 3/4" SS jacketed flex hoses and a made up double 90* (180*) "U" bend.
Looked at the nipple inline check valves, but they looked too restrictive for better water flow volume/rates.

I have a spring-check on the outlet of my water heater...it prevents gravity circulation through the main piping. Previously there was about 10' of copper that was always hot, but not anymore. Flow rates seem unaffected.

Rob R. wrote:JRDepew wrote:
Finally, are any brand of mixing valve more robust than the other.

I prefer the Honeywell units.

I will add that I like the sweat/union connection Honeywell units because they are easy to install, and easy to service. You can also take them apart for cleaning if needed.

Highlander wrote:

-Burned to much coal. Really would like to know how highlander does it at 7 to 10 lb a day.

My boiler doesn't use the standard Harman timer, I designed a PLC based control system for it that runs the stoker only as much as needed to maintain 140 Degree water temperature. I also control the blower speed to limit the amount of air the blower pushes through the boiler, just enough to keep the fire happy, but not so much as to push heat up the chimney.

PC063087.JPG

PB083708.JPG

Good Gawd! You have made one heck of an investment on all this control equipment my friend. This probably is the most advanced control setup ive seen so far.

highlander that looks like an amazing setup, I have just the rheostat/low combustion blower speed control on mine and am at maybe 18-20 lbs/day. Granted my wife does not go EZ on the hot H2O, can I ask how much your plc setup reduced summer consumption from just the standard combustion blower mod? Did you see significant savings in the shoulder heating season as well with this?

I may be able to go slightly lower on consumption, but I am really sick of dealing with the surprise out-fires on humid days, your setup seems to take that into account with monitoring and acting on flue temp.

I'm at about a skid of blashak (2400lb) for a summer of DHW (June-sept w/ no heat calls where its DHW only) , so at 260/ton or $.13/lb if I could cut summer consumption in half it would be about $150 saved annually. I am in a outbuilding so extra summer heat is not an issue, when I took my electric H2O tank offline it knocked my bill down roughly $70/month, so from june-sept where there are no heat calls i'm paying roughly $300, or $20-$30 more than what electric is for a summer of DHW + extra ash emptying and hopper filling, a small price in my opinion for keeping things rust free.

Highlander wrote:

-Burned to much coal. Really would like to know how highlander does it at 7 to 10 lb a day.

My boiler doesn't use the standard Harman timer, I designed a PLC based control system for it that runs the stoker only as much as needed to maintain 140 Degree water temperature. I also control the blower speed to limit the amount of air the blower pushes through the boiler, just enough to keep the fire happy, but not so much as to push heat up the chimney.

PC063087.JPG

PB083708.JPG

Thanks for the interest in the system.

I design control systems for industrial machines and processes for a living so this was a natural for me.

The PLC is a micro, made by Crouzet. It uses a function block type of language and can handle analog as well as digital signals. They have a built in display that can be used to display different values and allow the user to modify them as well. They cost less then $200.

The control system monitors the boiler water temperature and uses a proportional-integral method to run the stoker. The Harman timer runs the stoker continuously when the boiler water falls below the set point. With the Harman On-Off control scheme, a lot of coal gets dumped on the grate before the water temperature finally rises. This wastes a lot of coal and causes large swings in the water temperature. It isn't so bad in the winter when there is a demand for this heat and it isn't all wasted, but in the Summer there is none so all this extra heat goes to waste. The analogy I like to use is trying to cruise your car at 30 mph while alternately flooring the gas pedal and then coasting. It works, but its not real efficient.

When I sense the water temp below 140, I gradually ramp up the on to off time of the stoker to bring the fire up slowly and avoid this overshoot.

The combustion blower runs at a slow speed when not stoking and at full speed when it stokes. If heat demand increases past 50% load, it funs full speed.

There is a sensor that monitors outside air temp and raises the boiler water temp when the weather gets really cold say 10 degrees or so, this is called reset control.

The system also monitors the flue temp and if it falls below a preset temp for a specific time, it shuts the stoker down and switches to a backup electric heat system.

If you wonder why electric, all I have to say is its cheaper then propane.

The electric heat backup uses (3) 4.5KW sandhog elements in a series of pipes behind the boiler, with a second circulator and a flow switch to confirm sufficient water flow. The PLC then cycles the water heater elements on as necessary to maintain the boiler temperature at the preset level. The electric heat can also backup the coal if the water temp falls too low for too long by adding heat back to the boiler. The only time I recall it kicking in is in the dead of Winter, and then only for a short time.

My annual coal usage is about 4-5 tons for a 1600 sq ft house in northern NJ. On cold winter days it can burn about 2 buckets per day or about 70#, but that is only on real cold days.

Bill

We just went eight full days on only 94 lbs. of coal for our homes DHW. That's closing in on the cost efficiency of an electric hot water tank.

What kind of power do those Nyle units use?

lsayre wrote:We just went eight full days on only 94 lbs. of coal for our homes DHW. That's closing in on the cost efficiency of an electric hot water tank.

Just yesterday I completed the month of June at a total of 378 lbs., which comes to only 12.6 lbs of anthracite burned on average per day for the month to provide the homes DHW. That's about $45 of coal for the month. Only a few days worth of Harmony left in the AHS though, and then its back to Blaschak.

plumber wrote:What kind of power do those Nyle units use?

from the mfgr...

Suitable for any regular household outlet (110V/60hz; draws 5–7 amps)