Water Heaters

Originally Posted By: Steven Brewster
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Hey folks,


Has anyone seen an installation as seen in the photos. I would think that the gas and electric would compete with each other. Both are supplied by the same incoming pipe and distribute to the home on the same pipe.


[ Image: tandem water heaters ]

Any thoughts?


Originally Posted By: thejnicki
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What is the size of the home, does it need two water heaters??


Originally Posted By: bking
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No problem with that, each tank will heat up until its t-stat is satisfied.


The only thing that might occur with the electric one is stacking. This is when many small amounts are drawn out and the element comes on several times and "stacks' heat causing the temperature to be excessive.
This can happen with a single tank too, read about this in owners manual once. Still not a real problem as long as the overtemp cutout works. The overtemp cutout kicks in before the TPR would have too.

Does anyone know when the overtemp cutouts were incorporated in the t-stats ? I know mine in 1985 had it.


--
www.BAKingHomeInspections.com

Originally Posted By: Steven Brewster
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Thanks for the replies The home had been added onto and there are 4 baths and 2 kitchens with dishwashers. Think this was an amateur attempt to solving a water heating problem with so many fixtures to serve. The buyer will remove both of these and install a 60 to 80 gal heater.


Originally Posted By: pdacey
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Another potential problem is that the smaller unit is installed lower than the other one. With the shared cold water inlet, it could possibly siphon water out of the larger unit when a fixture is being used that draws from the smaller one.



Slainte!


Patrick Dacey
swi@satx.rr.com
TREC # 6636
www.southwestinspections.com

Originally Posted By: rcooke
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Steven Brewster wrote:
Hey folks,

Has anyone seen an installation as seen in the photos. I would think that the gas and electric would compete with each other. Both are supplied by the same incoming pipe and distribute to the home on the same pipe.


[ Image: tandem water heaters ]

Any thoughts?

I might be mistaken but when I made the picture larger and brighter it looked to me like they are in series.
I have seen this before but not side by side .
A long home had a small tank at the other end of the home so they could get warm water instantly.
I also could not see a TPR valve on the tanks did they both have one .
Could this have been Propane gas and it cost more and electric that cost less .
They had two in case of power outage?


--
Roy Cooke Sr.

http://Royshomeinspection.com

Originally Posted By: wdecker
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What are your thoughts, or better yet, actual knowledge, when two water heaters are used.


1) Install in series or parallel?

2) Expansion tank a must?

3) If different sizes and in series, which one first.

Have seen a number of these in all kinds of differnet configurations. Just wanted to know if there is a 'right' way that I could recommend.

Thanks;


--
Will Decker
Decker Home Services
Skokie, IL 60076
wjd@DeckerHomeServices.com

Originally Posted By: rcooke
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wdecker wrote:
What are your thoughts, or better yet, actual knowledge, when two water heaters are used.

1) Install in series or parallel?

2) Expansion tank a must?

3) If different sizes and in series, which one first.

Have seen a number of these in all kinds of differnet configurations. Just wanted to know if there is a 'right' way that I could recommend.

Thanks;

I have only seen it once and it did not bother me .
It was small electric in the crawl space.
1) Installed in series about 40 feet from primary heater.
2) see no reason for expansion tank.
3) Primary heater largest.
These are my thoughts only others may have other ideas.


--
Roy Cooke Sr.

http://Royshomeinspection.com

Originally Posted By: kmcmahon
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I see it all the time…nothing wrong with it from what I saw.



Wisconsin Home Inspection, ABC Home Inspection LLC


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Originally Posted By: wdecker
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Which is Primary. The one closest to the water supply?



Will Decker


Decker Home Services


Skokie, IL 60076


wjd@DeckerHomeServices.com

Originally Posted By: bking
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I have my two electric ones setup in series with a 220v switch for the first one on the incoming supply. It is just a holding tank until we have company and then I turn it on. In the summer the cold well water warms up some in the holding tank from the ambient heat in the garage.


I have a hot water circulation pump on a timer so check valves are present and had to install an expansion tank too since the check valves prevent using the supply line for that purpose.

Series works for me, other applications might be better with parallel setup.


--
www.BAKingHomeInspections.com

Originally Posted By: mcyr
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Although I can not tell by the picture if this situation is in parallel or series, it might be conceivable to have the primary gas fired water heater set to a temperature of 130 degrees and the electric water tank is set at a temperature slightly lower and more or less used as a storage tank. The storage would maintain the temperature to 120 degrees or as required and fed with the larger tank.

Since the piping is unclear, these are just my thought as to the logic behind having two tanks.

Marcel


Originally Posted By: bking
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Those are in parallel, both tanks get direct cold water. Series is where the hot output from one feeds the cold input of the other.


The only reason to use the words primary and secondary when talking about parallel tanks would be to describe the temperature settings.

When tanks are in series, the primary tank could be either one depending on whether you choose to use flow or temperature as the topic of conversation.


--
www.BAKingHomeInspections.com

Originally Posted By: ecox1
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I see this all the time. But I always not it in my report. Protect yourself.


Originally Posted By: mcyr
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I agree with Earl in that we should note and report that a recommendation is required from a licensed Plumber and Heating Contractor for full evaluation of the set-up.


Marcel