Dual Gas Hot Water Heater - Low Temp

[Jake12]

We have two 40 gallon water heaters set on high and we get hot water for less than a minute??? The system is 6 years old. We had a plumber out and they said everything is ok but obviously they don't know what they are talking about.

I came across this piping diagram for BW heaters.

http://www.bradfordwhite.com/images/shared/pdfs/Piping/2H_TCNR.pdf

Ours is piped with cold coming into heater #1 then hot going to heater #2 and then hot going out into system. Is this "normal" install or could that be causing a problem?

What else should we be looking for???

We ran sink that is less than 20 ft from heaters and got the less than 60 second hot water and then it went to luke warm for 5 + minutes???

Help....:

 

[Marv]

Do you have a water softner? Use its bypass valves and see if the softner is slowing the hot water flow.

 

[Sponsor]

 

[hj]

heaters

The way it is piped will give you the maximum hot water. Are both heaters operating? If so, then you may have a problem that has nothing to do with the water heaters themselves.

 

[Jake12]

Yes there is a softner. That line T's in to the cold water line feeding the rest of the house and then within a foot of that there is another T that goes back / down to the water heaters. The main supply comes directly into the softner and then feeds cold and hot as described.

Are both heaters working? Yes - It took a long time 20 -30 minutes to run the second one down enough to get it to kick on at high but it finally did.

the pipe between the two heaters seems plenty hot (can hardly touch)

 

[MACPLUMB]

Hot Water Supply

No No No That Is Not The Way To Get Max, Output Go With The Bradford White Diagram,
Otherwise When In Series The Second Wtr/htr Is Just Coasting
Like Riding The Handlebars Of A BICYCLE

Your Problem Is Related To A Cross Connection Between The Hot And Cold Supply Pipes, ? ?

Check If You Have Any Moen Faucets They Are Famous For This,
Also Turn The Water Off At The Washing Machine Connections ? ?

Something Like This Is Causing Your Plumbing Problems,
But If You Want Max, Output Run Your Wtr/htrs The Way The Mfg's Spec,

 

[Jake12]

OK

1. You are suggesting turn off supplies to Washing Machine and then testing?

2. We'll check mfg. of faucets and ask for recommendations if they are Moen.

There are only two people in the house. Good example is we can't even get enough hot water to fill the tub. You get a few inches of hot water and then it turns too cool to fill with hotter water. So there is obviously plenty of supply.

I made a small sketch but can't find a way to post due to file size in Word. Can't I copy and paste it here?

Thanks for all of the feedback

 

[MACPLUMB]

No Hot Water



YES CHECK YOUR SINGLE HANDLE THE MOEN USER'S A CARTRIDGE THAT HAS TO BE REPLACED IF IT IS CROSSING OVER THE WATER MIX, IT IS A PROCESS OF ELIMINATION TO FIND WHAT FIXTURE IS CAUSING THE PROBLEM,

 

[Master Plumber Mark]

cross connection somewhere

the way you have the heaters hooked up is the best
it is called series, you will get the max amount of hot water
that way...with far far less problems.....

the other way is called parrallel , which can
lead to all sorts of problems with the system
drawing only off one heater instead of drawing off both equally....

I have fought for days trying to get a parellel
system fine tuned to draw off both equally ,
and it simply cannot be done...
you cant even be sure that it is drawing correctly
with the parallell system without installing flow meters in the lines....

and eventually a union will corrode shut and mess
up the draw off both of them anyway...


or down the road if one tank starts to leak,
and you cant match up the new unit to draw right with the old unit,
and then you have another nightmare on your hands.


stick with the series approach , dont EVER change that ,
it does much better over time...


you probably have a bad cross connection somewhere
especially if you have the moen faucets.....
if they hae shut off valves, shut them down and see if
the problem goes away....

shut off your laundry too


or something else you have over looked,

possibly a bad dip tube in one or both of the heaters.

or ...of you are living on a slab home , could you have
a hot water slab leak??

 

[hj]

heater

If it took that long to draw down the tank before it turned on, WHERE did the hot water go if it was not coming out of your faucet? Do you have a recirulation system connected to the water heater?

 

[Jake12]

Sketch of system as it is.

 

[Master Plumber Mark]

have you found the problem yet??

just wondering if you had found the problem yet


the drawing looks ok..