I've read a little and spoken to a few people. They appear to be pretty efficient and one person said they have a long life. Does anybody have any experience with them?
Matt
Matt
jharkin said:We have an indirect running on our gas fired steam system.
The boiler is an 3 year old gas fired Burnham Independence (83% - about as good as it gets on steam). Its hooked up to a 40 gallon Superstore Ultra. I have all the steam lines heavily insulated but haven't yet gotten around to insulating the short loop to the tank.
There are 2 of us and our summer time gas usage is around 25 therms/month for the hot water. The one annoying thing is that we do run out of hotwater if you take back to back showers. Either the recovery rating on the tank is really optimistic or the circulator is starting to crud up from the corrosive steam boiler water - haven't had time to try and sort it out ...
As always you will probably get more advice thn you can use if you post this question on the wall over at heatinghelp....
btuser said:When you say back to back showers, do you mean two people in two different bathrooms simulantously? Do you still have the lag in the Winter, when the boiler is hot?
EatenByLimestone said:How big is your boiler?
jharkin said:Jimmie you made some great points.
Run off a 95% plus mod-con I'm willing to bet a well insulated indirect heater is almost as efficient as a separate tankless, plus cheaper to install and maintain. And the hot water is instantaneous....
btuser said:Very long life. Seasonal efficiency is dodgey. There's essentially no loss during the heating season, but Summertime is a different story.
Even with a 3 pass well-insulated boiler you're going to get heat loss. I've figured mine to about 1200-1500btu/hr heat loss during regular usage here in July, so if you figure 24hrs @ around 30k heat loss, I'm losing about 30-40% efficiency during the Summer months to heat loss for hot water. I heat with oil. My boiler is well-insulated and I have flowchecks to stop gravity flow on both return and supply. The boiler header/near piping is not insulated right now, but I don't feel that's where the heat loss is coming from. Its the 22 gallons + 500lbs of steel that needs to be heated up whenever someone calls for even a small amount of hot water. Something's up with my auquastat.
I'm currently trying to "dial in" my indirect, so I get longer times in between firing. Originally, my auqastat sensor was all the way at the bottom of the tank, and I think by raising it to mid level I may be able to eliminate some of the nuisance firings I'm experiencing. My boiler is cold-start, but I never see it go below 140 degrees because of a call for heat. I have a mixing valve and maintain tank temperature around 140 degrees, but because the auquastat bulb is pushed to the bottom of the tank, I think the aquastat is interpeting the inrush of cold water as a need to recharge. I'm slowly raising it about 2"/day to see if I can get the boiler to stop firing so often and yet not run out of hot water. If you heat with wood and have storage then you've pretty much already have an indirect, just need a coil.
Long answer short: Very efficient during the Winter, and if you have a tub/large draw at once it is a great option for a lot of hot water all at once. Summer months are really going to depend on whether you have gas and can modulate a low-mass system, or whether you have oil which is only one speed.
SO why dont you bypass the ID -WH in the summer and just let the oil furnace heat heat the water,never saw an oil furnace that did not also have a domestic coil in it.
mayhem said:I hate my indirect water heater. Very inefficient. I'm guessing I've got someosort of problem thats been present since new though and just have enver been able to track it down. Wash your hands with warm water in my house and you're gonna kick the boiler on for 10 minutes because that little bit of hot water out of the tank will trip the thermostat.
Hot water storage is also a lousy way to go IMHO. My boiler cycles minimum of 5x a day with no hot water usage, just to maintain the tank.
It costs me the same amount of oil to wash my hands as it does to take a shower or to fill the tub, despite using probably 1/100th the amount of water. Before I figured out the pattern when the house was new, we were using about 500 gallons of oil in the warm months (ie: non heating season), now that we wash our hands and most of our clothes in cold water we're down to a more livable 200 gallons or less.
If I could easily swap it out myself for solar or even electric I'd do it.
mayhem said:system is filled with noburst glycol for the heat transfer fluid and I'm fairly confident that needs to be changed as it was new with the house (installed in late 2002). Not sure of the brand water heater. I've turned the H2O thermostat on the tank down to the minimum and whiole it made an impact, its a point of diminishing return and, in my opinion, just a band aid over the high usage and not actually correcting the problem.
btuser said:I thought about the glycol as well, but with such a high-firing boiler I doubt it's lack of btus that is keeping his indirect from fuctioning. I'd be curious to see how it's firing.
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