Water heater to coil exchanger

[RHD 4 LIFE]

Has anyone on here ever ran a system similar to this? I'm thinking of running off the NG water heater in the house, out to a A/C coil with a fan and inline pump on a timer in a loop fashion.

So hot water out side of heater to ball valve with drain, on to pump with timer, out to coil with pusher fan on same timer, return line to ball valve with drain, into cold inlet on water heater!

Drains ar so I can empty it in the nicer weather so i dont get stagnent water.
I was thinking I can run one hour on, two hours off sort of thing?!
I could later install a thermostat as well if needed, and my garage never really gets below freezing anyway.

Any input is welcome.

Thanks in advance
John

 

[anthony666]

what are you gonna do for freeze protection ???

 

[djjsr]

If I understand this correctly, you want to use your domestic hot water (potable) to heat your garage by running it through an a/c coil?

 

[RHD 4 LIFE]

Yes, but it is a reclaimed and cleaned A-coil that will be out in the attached garage at a 15' run from the water heater!

As for freeze protection I am not too concerned! As I said it does not get below freezing in there, I keep my bottled water and pop out there and none of it has ever froze on me. It is insulated and sealed, just not heated.

 

[philjafo]

There are air handlers designed just for the application your describing, I would suggest getting one of those. Ac coils are not designed to flow water through them and I definitely wouldn't want the oil from inside there mixed with my drinking water.

 

[anthony666]

an air handler is mounted into a duct system, like a furnace

what you're after is a hydronic unit heater .. i've seen them rigged up from old car rads with a box fan behind them, works great but looks a bit trailer park ghetto meets meth lab land fill

they're pretty cheap to buy new, and don't look like dog **** .. it's got a fan, clean packaging, provision for controls, air directing slats; add power, hot water and you're good to go

http://www.pexsupply.com/Modine-HC-18L-01-HC18L01-Hydronic-Unit-Heater-15900-BTU

also, since you're talking about running your domestic hot water out there you're gonna need to use bronze pumps for your application

 

[RHD 4 LIFE]

There are air handlers designed just for the application your describing, I would suggest getting one of those. Ac coils are not designed to flow water through them and I definitely wouldn't want the oil from inside there mixed with my drinking water.

The coil will be flushed out so no oils! I was also thinking with the smaller diameter pipe it would slow the water down to help with heat transfer!?

an air handler is mounted into a duct system, like a furnace

what you're after is a hydronic unit heater .. i've seen them rigged up from old car rads with a box fan behind them, works great but looks a bit trailer park ghetto meets meth lab land fill

they're pretty cheap to buy new, and don't look like dog **** .. it's got a fan, clean packaging, provision for controls, air directing slats; add power, hot water and you're good to go

http://www.pexsupply.com/Modine-HC-18L-01-HC18L01-Hydronic-Unit-Heater-15900-BTU

also, since you're talking about running your domestic hot water out there you're gonna need to use bronze pumps for your application

With a price like that I might as well install a Mr. Ready Heater!
Bronze pump I knew that as well. Thanks!

 

[philjafo]

Just curious, what method will you use to flush the coil and how will you be certain that there is absolutely no residue left inside?
www.barsco.com/MSDS Sheets/MSDS/diversitechwagner-alkyl.pdf

 

[RHD 4 LIFE]

Concentrated Simple green flush followed by Dawn dish soap flush, then run clear hot water!

 

[Jim_No_Garage]

I'd be surprised if it's "allowed" to have a recirculating hot water loop "sharing" your Water Heater.

Your potable water would be mixing with the water coming back from the heating loop which is not allowed her in NJ. That water would get a bit "funky" during the non-heating system - even if drained.

We were toying with the idea of installing hydronically heated floors in the bathrooms and gave up when that requirement was explained. Wife still talks about it when winter first hits every year . . .

Cheers

Jim

 

[philjafo]

There are water heaters that have a separate heat exchanger inside specifically designed for hydronic heat, that would keep the funk out of your drinking water and in turn out of you.

 

[Jim_No_Garage]

There are water heaters that have a separate heat exchanger inside specifically designed for hydronic heat, that would keep the funk out of your drinking water and in turn out of you.

Philjafo : That's useful information - thanks for passing it along. Any specific brand/model with that capability? I'm sitting on a 12 year old gas fired WH so I need to plan ahead . . . .

Jim

 

[philjafo]

AO smith, check their website I'm not sure on which specific models.

 

[brewchief]

I'd be surprised if it's "allowed" to have a recirculating hot water loop "sharing" your Water Heater.

Your potable water would be mixing with the water coming back from the heating loop which is not allowed her in NJ. That water would get a bit "funky" during the non-heating system - even if drained.

We were toying with the idea of installing hydronically heated floors in the bathrooms and gave up when that requirement was explained. Wife still talks about it when winter first hits every year . . .

Cheers

Jim

Philjafo : That's useful information - thanks for passing it along. Any specific brand/model with that capability? I'm sitting on a 12 year old gas fired WH so I need to plan ahead . . . .

Jim

There are hot water/fan coil units that use the potable water in use pretty commonly, I know some of them have a timer that will automatically run the pump for a few minutes every so many hours.

Bradford white has some water heaters with built in heat exchangers as well, I'm not sure how the cost compares to simply using another pump and a plate type heat exchanger however.




To run water through an A/C coil it would need some rework to get a decent amount of water flow through it due to the small size of the lines feeding it on the liquid side(cap tubes or distributor lines depending on coil type).
I honestly don't think you will get a coil clean with simple green and soap, there is no way I would connect a A/C coil into my potable water.

 

[RHD 4 LIFE]

I think I'm going to look into another sort of exchanger then!
Thanks for the feedback, much appriciated!

 

[VHF]

Did you have a specific reason for wanting to use your domestic water heater to heat your garage as opposed to just installing a NG garage heater? That would avoid all the issues with circulating your potable water through a heating system, would probably be a little more efficent, and might be less expensive. Only drawback would be needing to run a gas line and vent(s), although it sounds like the gas line wouldn't need to run very far.

 

[sprntpshr]

As noted above, unless you remove the orfice tubes/piston from the "A" coil there will not be sufficient water flow to cause the desired heating effect. Then you would find a high head type situation for a pump to work against.

If you are returning the water to a potable water system, all the parts in that heating system must be new as well.

A fan coil unit with a blower and designed water coil as used in many condo units will serve you better.

 

[RHD 4 LIFE]

I just didn't see the point of adding another water heater if I didn't need too! As for the orfice tubes they were removed in preperation for this. If I was going to run a gas line your right its not far and I just dont want to add more vent tubes to the side of the house! Trhe biggest reason is it is brick! Not that I can't, I just don't want the extra holes in it for re-sale reasons. If I was to put a garage heater in they are $500 here, then a gas line and install, permit and inspection! Climbing up over a grand now!
Not worth it in my books!

 

[felixmtt]

Yes its true that water heaters come with built in heat exchangers but in case you dont find it. You have to add it externally. I suggest that you do it externally so that its safe enough.