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[slimjim]

Hondaracer, I'm not saying that the extra 50 gallons wont help at all but I doubt that you will see a difference, what I do think would make a difference is adding thermal mass inside the firebox in the form of firebrick, it will help to insulate the fire from the water jacket to keep the coal bed hot, does this not sound more like what you want to accomplish? For those on here that don't like firebrick, all you have to do is look at our chip boiler with brick added and then without, it is auger fed at variable speed with a measured amount of fuel, the brick added keeps the pot hot enough to relight the chips far longer and it burns much cleaner with added brick.

[Scott7m]

Hondaracer, I'm not saying that the extra 50 gallons wont help at all but I doubt that you will see a difference, what I do think would make a difference is adding thermal mass inside the firebox in the form of firebrick, it will help to insulate the fire from the water jacket to keep the coal bed hot, does this not sound more like what you want to accomplish? For those on here that don't like firebrick, all you have to do is look at our chip boiler with brick added and then without, it is auger fed at variable speed with a measured amount of fuel, the brick added keeps the pot hot enough to relight the chips far longer and it burns much cleaner with added brick.

Slim if you add firebrick to most of these conventional boilers and it insulates the fire from water jacket where is it supposed to pull its heat from?  I understand fully how it works but without heat fire tubes it could actually hurt the performance

[yoderheating]

I have never understood the fascination by some with extra water storage. On 99% of systems it is not needed or desirable. Maybe if you had a huge load kick in at one time it would help but in all other cases its a waste of time. Why store a bunch of heat when it isn't needed? I keep me heat stored in wood because any stove worth its salt should be able to heat water faster than it can be pulled off. If your system uses heat faster than the furnace can produce it you would most likely need to get a furnace with a bigger firebox anyway.

[hondaracer2oo4]

Yoder,
 
    It isn't about the fact that a stove could be able to keep up with the demand load. It is the fact that a longer hotter fire is more efficient than a short burst of fire that spends the first few minutes getting the fire back up to temp, then puts out some good heat for a few minutes and then shuts off the damper and slows back down. If you had a larger mass of water the fire wouldn't have to do these cycles as often and the fires would be more efficient. For me, I have a 24x24 water to air hx. My Delta T is about right on at 22* across the hx but I am also moving alot of water as well. My stove works pretty hard for me when its cold meaning it cycles often. When it gets real cold out, the time between firings is usually pretty short so the extra water probably wouldn't help in those circumstances but this time of year when the temps are in the 40s during the day and 20s at night I believe it would help to get a longer, more efficient burn. I am hoping coolidge will report back on what he found, his water mass is much larger than mine would be.

[CountryBoyJohn]

If I may chime in, I think there is a point at which a "long burn" is long enough.  When my stove fires for a 15 degree drop, by the time the temp starts walking back up, that fire is raging!  I think that there is a point at which the fire reaches a maximum temp or intensity and it stays that temp for the remainder of the burn.  Therefore, I would think that a burn that lasts 15 degrees of water temp swing for 200 gallons is the same amount of clean as a 15 degree swing for 500 gallons.  I would argue that a 30 minute burn is just as clean as a 60 minute burn.   I think based on the discussions that I've read on here, that we can all agree that the fire box doesn't reach this max until longer than a 5 degree burn, but less than 20.  Otherwise, we'd all be shooting for a 30 degree swing or something like that.  I'm just swinging by the seat of my pants here, but that's what I was thinking. 

[f150bft]

I have a Hardy H4 which is 120 gallons. I was thinking of adding a 50 gallon hot water tank in the loop to add extra capacity to the system. Anyone think it is worth it?

Hondaracer, I am curious about the extra capacity idea. First off how would you go about doing it, where would you put the tank, would it require an extra pump or maybe a larger capacity pump?     Oh by the way the H-4 holds 130 gallons according to the online manual, but that may be the newer ones.

[hondaracer2oo4]

I think your right about the 130, 120 was a typo. I planned to just place it in series with the heat exchanger. I would put the supply line in through the bottom drain and continue it out through the hot supply if the hot water tank. I would plug the cold in to the tank

[coolidge]

Ok  Taking the tank of the system didn't make much of a difference at all. Saturday and Sunday the boiler had a cycle 1 extra time,230 ish. I did not time it Saturday but Sunday it ran for 13 minutes, 2 minutes to full gasification, so actual "burn" time was only 11 minutes. It did not cycle again until 830 at night. I don't see the benefit. Mine was because I only had to buy two valves to hook it up and it also helps when I forget to turn the blower on.

[hondaracer2oo4]

Not sure how the temps were where you are but they were mild here in New Hampshire. I would be interested to know if it made a difference when the average temps were in the 30s. Interestingly enough maybe it wouldn't be worth putting in the extra capacity.

[coolidge]

It was warm, I am just over the border  from you in Maine.Where abouts in NH?

[hondaracer2oo4]

Canterbury, about 10 minutes away from the Nascar track. Where are you?

[MattyNH]

Canterbury, about 10 minutes away from the Nascar track. Where are you?

Im right next to you..Alton here..

[hondaracer2oo4]

Matty, Yeah short ride over to Alton from here.

[coolidge]

About three hours from you in Maine, been through your area more than once.

[hondaracer2oo4]

You must be far north up the border?