Assistance Requested - Hot Water Heater Install Piping/Expansion Tank Question

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Old 09-30-14, 07:38 AM
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Assistance Requested - Hot Water Heater Install Piping/Expansion Tank Question

I have chosen an Alliance AL50SL indirect water heater, to complete my system. The system was designed by NJTrooper and has been built per the plan. Here is the link to that thread

http://www.doityourself.com/forum/bo...istance-2.html

Please see post #30 for a view of that design.

My question is as follows....as I reveiw the install instructions for the water heater, they say that a 2nd expansion tank is recommended. I wanted to get feedback on whether you think it is required.

Here is the link to the install instructions.....Page 12

http://s3.supplyhouse.com/product_fi...SL-Install.pdf

Thanks

Kevin
 
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Old 09-30-14, 08:39 AM
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Recommended, but not required.
Read this informative page from Watts
Thermal Expansion - Learn About - Watts
 
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Old 09-30-14, 08:52 AM
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REQUIRED if your city water service meter includes a CHECK VALVE or BACKFLOW PREVENTER which most of the new meters do.

Older water meters may not have the check or backflow valves and in this case the city water system would absorb the expansion and pressure from the expanding water.

NOT required if you are on a private well system AND you well tank has the capacity to absorb the expansion of the domestic hot water.
 
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Old 09-30-14, 10:00 AM
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Okay so i am on city water. No back flow preventer , nor do i have a check valve. That all being said if I wanted to do such a tank, how does it get installed? upside down, right side up, or doesnt it make a difference? Do I need a special connection like I have on the heating system expansion tank? Lastly what size tank would you recommend for a 50 gallon tank?

As always, thank you for your guidance.

Kevin
 
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Old 09-30-14, 02:48 PM
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nor do i have a check valve
How do you know? It may be built into the water meter...

how does it get installed?
Pretty good info here... Installing a Thermal Expansion Tank for an Electric Water Heater

I prefer them hanging... this way you will know if the bladder is bad by 'blipping' the air valve... if you get water, it's bad. The instructions above show hanging as well. I've seen plenty standing on their heads. I don't think it really matters much.

Don't use the 'saddle valve' that the instructions suggest. They eventually give trouble.

Do I need a special connection like I have on the heating system expansion tank?
You mean like an 'air scoop' ? No, just a threaded tee fitting. You could add a valve and drain as shown in this thread (scroll to the end) to facilitate servicing the tank in the future:

http://www.doityourself.com/forum/bo...sion-tank.html

Lastly what size tank would you recommend for a 50 gallon tank?
Probably a 2 gallon... there's a calculator here:

Potable Water Expansion Tank Sizing - Support - Water Safety & Flow Control -Watts
 
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Old 10-01-14, 12:59 PM
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NJ Tooper

I spoke with the water department. In my town they do not use check valves nor backflow preventers on residential systems. I think I will just go ahea and install one. Easy to do while the system is being worked on.

Thanks

Kevin
 
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Old 10-01-14, 01:11 PM
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Why not just install the threaded tee and put a plug in it? If and when they go with the backflow stuff, pull the plug and hang the tank.
 
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Old 10-02-14, 08:43 AM
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Fantastic idea.....one last question for now

I was reading the thread on heat traps and know this will apply to me. I am not clear on how to build a heat trap from copper pipe. My question is do I need to build one? and if so how do I configure the pipes to form the trap

The cold water supply to feed the hot water heater will drop down from above (it runs along the floor joist from the room above, And the hot water side will exit the hot water heater and travel back up to the line that will supply the house. This line also runs along the floor joists as well

Thanks

Kevin
 

Last edited by Teke1; 10-02-14 at 10:58 AM.
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Old 10-02-14, 01:54 PM
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Basically you elbow off the hot outlet toward the side of the tank, elbow down to about a foot or so below the top of the tank, elbow horizontally again to a short length of pipe, then elbow back up again and connect to the piping to the home.

You just need to form an upside down " U " shape so that the hot water can't float out of the tank.

Because the cold water going into the tank goes down a 'dip tube' inside the tank to the bottom, there really isn't much need to heat trap the cold, but it wouldn't hurt if you did.
 
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Old 10-14-14, 12:36 PM
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Hi Trooper

Getting ready to pipe this hot water heater up. As you may recall I ran 1 inch pipe for both the supply form the boiler to the water heater and also on the return. The hot water heater is a 3/4 bolier supply and return, does it make a difference where I reduce the line from 1 inch to 3/4 on the supply side? Would right before the connection to the HW tank be okayto place the reducer?

Thanks,

Kevin
 
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Old 10-14-14, 03:46 PM
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You're going to install unions on the connections as recommended in the install, yes? You want these so that the coil can be removed for servicing if necessary. Make sure when you pipe it that you'll be able to get to the bolts.

I would probably reduce at or close to the unions. 3/4" unions might save ya a few bucks, so it might make the most sense to reduce to 3/4", then to the union, then to the tank.
 
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