Hot Water Experiment

We had a good discussion last week about the BTU demands of water heaters. How Many BTUH Does Your Indirect HWT Demand of Your Boiler?

It got me thinking about the size of my indirect water heater, and if it was way overkill or not for what I am doing....so last night I did an experiment. I had shut the boiler down late in the afternoon b/c I was doing some wiring, and decided to leave it off and see if the hot water stored in our 80 gallon indirect was enough to get through the kids baths, dishes, etc. I started the dishwasher, started the washing machine (on warm), gave each kid a bath (2), and took a shower. I only stayed in the shower for 6-7 minutes, but there was no indication of running out of hot water when I shut it off. Survey says...could have went with a smaller water heater, especially if I installed a mixing valve and kept the tank at a higher temperature.

When we first moved into this house it had a 30 gallon indirect that could not keep up with the hot water demands of just my wife and I. I decided to "go big" and install the 80 gallon unit - but since then we have also purchased a new washing machine (front loader), new dishwasher, and I have installed low-flow showerheads. In hindsight, I probably should have looked at reducing our hot water consumption before I purchased the biggest water heater that would fit though the basement door.

Oh well, if I ever want to install a carwash or something I should be all set with hot water.

Let your hot water run out right in the middle of Momma's shower and you will look like a very sad man for not going with your instincts of "bigger is always better."

Right now to your family you look like a very smart person. My unsolicited advise is don't open your mouth and prove otherwise!!!! :punk:

I agree , I think this is alot like the "how much boiler do I need" discussion. I don't think oversize is a bad thing. It doesnt cost didlly squat as any standby losses go to heating your house. In the summer if your using an indirect you have standby losses from your boiler anyway the tiny bit extra for an 80 gal vs. a 30 gal is not worth talking about. Bottom line , go big or roll the dice...

I'm with Larry!!!!!!! Momma in the shower,,,,,,, cold water....... Rob in hot water!!!!!

It is all relative...
Standby losses minimal with indirect .5*f/hr...
Not running out of hot water at that critical moment...
Priceless...
We run short of hot water with a 40 gal indirect...
improper install is part of the issue...
But we have a very high demand long duration events...
So going up to a larger unit...

I agree, better more capacity then "just enough" or too little.

I'm running the larger 7 GPM coil in the EFM, that's it. Under high demand, especially if the boiler has been asleep for a while the water can start losing temperature. It takes a while for the fire to ramp up.

That said I really haven't had major issues with running out of hot water. If need be I still have the 30 gal. oil fired Aero water heater plumbed in and valved off. A few plumbing changes and a small circulator and I can have 30 gallons of hot water on hand, heated, of course, by the EFM.

Here the 40 gallon indirect has really been tested under the worst of conditions and never a problem. The colder the outside air temps the colder the incoming water temp is.

I took no shortcuts with the installation either. It is on a 3 speed zone pump with 1" pipe all the way to isolation valves at the indirect tank.
Icing on the cake was running indirect as a priority zone to cause all the other zones to wait until the indirect tank heat call is satisfied first.

Not to mention, this Axeman-Anderson boiler is like a Lamborghini.

Relax guys...I am not going to rip it out just for the sake of it being larger than needed. Mine should last a long time with the 3 anode rods...but it is so tall I can't remove them without disconnecting the tank and leaning it over.

I just thought I would share my results in case someone else is considering getting an indirect...compared to what I did, they can save a couple hundred dollars and still have excellent performance. When it comes time to replace my current water heater, I will probably put in a 40-50 gallon unit with a mixing valve.

The other part that no one commented on is conservation. Probably half the reason my previous water heater was not up to the task was that the old washing machine was a water hog, and the showerheads were high-flow models. I resisted changing the shower heads for a long time because I had heard so many bad things about low-flow models (wife can't get her hair rinsed, etc), but I did some more research and found a few models seemed to have positive reviews. One is a Kohler 2.0 gpm unit, the other is a High Sierra 1.8 gpm unit. I actually like the High Sierra one the best - it seems to have zero problems with mineral deposits.

http://www.highsierrashowerheads.com/

CapeCoaler wrote:We run short of hot water with a 40 gal indirect...
improper install is part of the issue...
But we have a very high demand long duration events...
So going up to a larger unit...

Fix the installation and consider setting the tank at 145 with a mixing valve.

I have a 2.0 GPM showered, have had it for years. It has a lever on it to shut off the water while "soaping up". Works very well.

I had a front loader water miser washing machine for a while until it self-destructed, I went back to the 1980's Whirlpool top loader, which uses a lot more hot water, but doesn't seem likely to implode any time soon. I did have to replace the timer a few years ago.

Wood'nCoal wrote:I agree, better more capacity then "just enough" or too little.

I'm running the larger 7 GPM coil in the EFM, that's it. Under high demand, especially if the boiler has been asleep for a while the water can start losing temperature. It takes a while for the fire to ramp up.

That said I really haven't had major issues with running out of hot water. If need be I still have the 30 gal. oil fired Aero water heater plumbed in and valved off. A few plumbing changes and a small circulator and I can have 30 gallons of hot water on hand, heated, of course, by the EFM.

The 350 has BTU's in inventory, but if set at spec of max 15 lb/hr it will make under 5 gpm going forward unless you have darned warm inlet water where you are.

Mike

My understanding is the 1/2" coil is 5 GPM and the 3/4" coil is 7 GPM, correct me if I'm wrong.

Lots of variables thrown in too, as you said...incoming water temperature, boiler feed settings, aquastat settings, etc etc etc.

Wood'nCoal wrote:I have a 2.0 GPM showered, have had it for years. It has a lever on it to shut off the water while "soaping up". Works very well.

I had a front loader water miser washing machine for a while until it self-destructed, I went back to the 1980's Whirlpool top loader, which uses a lot more hot water, but doesn't seem likely to implode any time soon. I did have to replace the timer a few years ago.

I don't disagree that the older washing machines were a lot more rugged...but I am not ready to go back. Other than using less water, our new one handles bulky bedding much easier, and the dryer runs a lot less. After the first year with this new washer/drier set I estimated that we saved $20 per month in electric.

I used the 5 gpm coil in my EFM for a few months. I may have been happier with it if I had already made the efforts at conservation, but overall I was pretty unimpressed with it.

Wood'nCoal wrote:My understanding is the 1/2" coil is 5 GPM and the 3/4" coil is 7 GPM, correct me if I'm wrong.

Lots of variables thrown in too, as you said...incoming water temperature, boiler feed settings, aquastat settings, etc etc etc.

Not sure of dimensions. I'm just talking about btu's.

Mike

The pipe sizes are correct. The 7gpm coil has 3/4" fittings, and can pull way more BTUS than a stock 350 can produce.

Understood, Mike. I''ve lost track of 350 output, I know I knew it at one time... Dammit I should have wrote it down!

My stoker isn't stock, Rob. In addition to the ratchet ass'y it has the adjustment on the gear reducer that was used on the models without the ratchet to adjust the feed. I have no idea how many lbs per hour it would feed if I cranked it all the way up. Trying to find the picture I have of it...would probably be easier to just go take another photo.