Water Heaters - water heaters?
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therookie
05-06-07, 10:03 AM
Can you connect 2 water heaters in a series?
core
05-06-07, 10:16 AM
Sure. And in my opinion (non-pro) it's better than a parallel setup.
If flow is not a problem, series will give you more hot water than parallel, because you'll get roughly 70% of the hot water from one tank and _all_ of the hot from the other before it's mixed with cold.
You could even set up bypass values so if one fails you can isolate it and still have hot water. (Check with codes about valving both sides of a heater though.)
If flow is not a problem, series will give you more hot water than parallel, because you'll get roughly 70% of the hot water from one tank and _all_ of the hot from the other before it's mixed with cold.
You could even set up bypass values so if one fails you can isolate it and still have hot water. (Check with codes about valving both sides of a heater though.)
CSG
05-06-07, 12:38 PM
I'm against running water heaters in a serious. It really depend son how much hot water your using...but what your really doing is making 1 hot water heater work more then the other. Just get 1 larger water heater in my opinion. Much better. Or go parallel if you want the redundancy of having 1 if 1 goes out. But series? I've seen a lot of plumber do this.
You empty the hot water from 1st heater..hot water from 2nd goes into 1st...all that happens is the 1st heater barely runs and the 2nd is constantly doing all the work...
You empty the hot water from 1st heater..hot water from 2nd goes into 1st...all that happens is the 1st heater barely runs and the 2nd is constantly doing all the work...
core
05-06-07, 01:02 PM
"The 1st heater barely runs and the 2nd is constantly doing all the work"
This is correct, IF you configure them that way. What I neglected to add is that if you don't need all that hot water (70% + 100%) then what you'd do is set the first heater at a lower temperature, say 110F. ("First" here meaning closest to cold supply.) Let the second make up the difference. Heh let's not get into the legionella debate.
Even disregarding that [optimal] setup, I personally see no problem with making one heater do most of the work. I agree that 1 larger heater would be better for a few reasons. I'm just assuming that the OP had a good reason for asking about this setup. (Free secondhand equpment? Space limitations?)
In series you have _automatic_ redudancy in case of heating element or gas-related failure. With a parallel setup the homeowner must first notice and then shut off the valve to the offending heater. With a tank leak situation yes you are better with parallel if you didn't install the bypass in the first place.
Running them parallel would of course be fine too depending on what problem you are trying to solve. But you're never going to be able to fine tune them such that they are balanced. Plus whatever balance you achieved today would be nowhere near the same after a couple years.
therookie, how bout you give us some more details on what you are planning to do and why?
This is correct, IF you configure them that way. What I neglected to add is that if you don't need all that hot water (70% + 100%) then what you'd do is set the first heater at a lower temperature, say 110F. ("First" here meaning closest to cold supply.) Let the second make up the difference. Heh let's not get into the legionella debate.
Even disregarding that [optimal] setup, I personally see no problem with making one heater do most of the work. I agree that 1 larger heater would be better for a few reasons. I'm just assuming that the OP had a good reason for asking about this setup. (Free secondhand equpment? Space limitations?)
In series you have _automatic_ redudancy in case of heating element or gas-related failure. With a parallel setup the homeowner must first notice and then shut off the valve to the offending heater. With a tank leak situation yes you are better with parallel if you didn't install the bypass in the first place.
Running them parallel would of course be fine too depending on what problem you are trying to solve. But you're never going to be able to fine tune them such that they are balanced. Plus whatever balance you achieved today would be nowhere near the same after a couple years.
therookie, how bout you give us some more details on what you are planning to do and why?
Pendragon
05-06-07, 11:03 PM
Or the best solution of all. Don't use a tank.
Go tankless, there are no space concerns and you never run out of hot water, regardless of how much you need.
Short of living on the north pole and getting your water from ice melts, units are available now to meet even the highest of flow rates.
Go tankless, there are no space concerns and you never run out of hot water, regardless of how much you need.
Short of living on the north pole and getting your water from ice melts, units are available now to meet even the highest of flow rates.
rjordan392
05-07-07, 03:08 AM
I would go with a larger heater and then install a large holding tank or a series of 4 inch pvc pipes with more capacity to feed the heater. When hot water is not being used, the incoming water in the holding tank or pvc pipes gets a chance to warm up to room temperature. Of course, the holding tank or pvc pipes should be installed downstream of all cold water discharges so as not to leave a differant taste to the water. I think rookie wants an efficient system to have plenty of hot water and to save on heating costs.
I would be concerned about the operational costs for series connected heaters vs a larger heater.
I would be concerned about the operational costs for series connected heaters vs a larger heater.