Backup for boiler failures

guyinsb

I have a 14-unit unit apartment, with hot water suppled from a common Rheem boiler:

<a href="http://picasaweb.google.com/stevej777/GardenWaterHeating?authkey=Gv1sRgCNHhrYK19t2CdA#5432626610700985362">http://picasaweb.google.com/stevej777/GardenWaterHeating?authkey=Gv1sRgCNHhrYK19t2CdA#5432626610700985362</a>

There is a big storage tank above the boiler.



This system seems to fail about every 5 years (tank develops a leak), usually at the start of a 3-day holiday weekend.  The residents get very annoyed after 4 days without hot water.  I would like to install some kind of system for temporary, emergency hot water backup; possibly a 30-gallon tall skinny electric water heater, or a tankless booster.

Any suggestions?  Thanks.

Larry Weingarten

photos

Hello:  Looking at the photos, it looks like the gas heater failed, but the overhead tank looks old and happy.  If it is the water heater that is doing the failing, replace anodes, check water pressure and make sure the air used for combustion is not polluted in any way.  Sediment  may also be a problem causing overheating and damage of the bottom head of the heater.  Keeping track of these things will give you many more years from a heater.



Yours,  Larry



ps. Do have a look to make sure all 14 units have hot water saving fixtures, then use one of the commercial sizing programs to make sure you don't install a heater that's oversized.

Charlie from wmass

You may want to try two other things

Install a carbon filter to reduce chlorine entering that heater and install an expansion tank on the domestic water as those heaters can really make the water swell when they fire.

SpeyFitter

Not bad, but bigger

Well a 30 Gallon electric hot water tank sounds a little small for "back up" but a larger electric (or gas) 75+ gallon tank might not be a bad idea to incorporate into the system permanently, say downstream of the storage tank (in series). Anytime water is moved, hot water from the storage tank will push into the electric tank subsequently causing the storage tank to do all the work as far as output goes which will help considering how much electricity costs, however IF/WHEN the boiler system fails the electric elements (or gas burner, if it's a gas tank) will at least pick up some/most of the demand until you can get the boiler repaired and the storage tank system back up and running. 

Thank, or stainless buffer/storage tank with a single element in the middle which I've seen before as well. This would last longer, however would cost more as well.

When your boiler system is due for replacement, plan on a system with some redundancy - say 2 boilers and 2 indirect tanks with each boiler heating it's indirect and if one boiler goes down, the other boiler can at least pick up most of the domestic load and some or all of the space heating load depending on what you go with.