I’ve given up on having the local HVAC guy call me back.
He installed a a takagi tankless in the garage which he said he’d hook up to an air handler to heat the upstairs apt and leave a supply (no return) for the lower level.
The takagi works great for HW for the apt. My retired union plumber neighbor has pointed out that the guy did not use WOG fitting for the gas connection outside, nor did he properly orient the regulator below the tankless. (I have 2psig coming out of the meter, the small reg for the tankless and a big reg for the whole “main house”)
Can anyone point me to a DIY solution? I’ve found good documentation on pump/loop setups for tankless and RFH, but nothing on air handlers? Do I just use an AC A-coil?
The guys out here seem to have a gentlemen’s agreement to not encroach into others areas.
Thanks.
Adventures in Home Building
An online journal covering the preparation and construction of our new home.
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The guys out here seem to have a gentlemen's agreement to not encroach into others areas.
Once you try to fix someones mistakes, you own the job...with any or all associated problems. That's why they are reluctant to show up.
At this point, I'd be happy if he'd just finish and I'd deal with the mistakes later.
http://jhausch.blogspot.comAdventures in Home BuildingAn online journal covering the preparation and construction of our new home.
No you don't use an AC coil. Not setup to handle water.
I think that hydro air is the generic term and you will find more information using that.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Google, "water to air heat exchanger"
Just happened to do that today....found retrofit exchangers, from a wood boiler outfit.
I'm looking for some finned stovepipe to use as a dryer exhaust, recapture some of that waste heat.......
The outdor boiler guys look like they have what I am looking for.
Thanks to both of the last two posters.
http://jhausch.blogspot.comAdventures in Home BuildingAn online journal covering the preparation and construction of our new home.
I use a tankless water heater to heat my garage, via in floor PEX tubing. The only diference in your case is the heat exchanger will be a hot water coil and not tube in concrete. So in the diagram(s) you have seen, replace the tubing with your hot water coil, and you have a good start for what your system will/should look like.
You have two issues to address for this to work properly, controls and piping. Your piping loop will consist of a circulator, expansion tank, air separator, the Takagi and an automatic pressure control valve on the feed line, in addition to the "terminal device" in your case a hydronic coil. Local codes and good practice also will require a backflow preventer on the water supply line, up stream of the PRV.
Tankless water heaters are fired on sensing flow through a microswitch, built into the unit. Your control system will need to start the circulator on a call for heat. Options for the system will be how the coil output is controlled during a call for heat. Simplest way is to let it "run wild", that is full flow with no modulation during a call for heat. The fan blows air across the hot coil until the thermostat is satisfied. Simple on/off control. Unless you know all this already, a more complicated control scheme is not recommended for DIY.
You can buy simple hydronic air handlers that will have the coil, fan, fan control board, and an insulated cabinet/filter housing in one package. MagicAire is one of the many that come to mind that I would recommend. Sizing the unit and coil properly are a diffferent subject, but not beyond anyone that can do basic math.
Thanks for the detailed response.
I figured as much for the controls. The radiantec site seems to have good information on tank and tankless RFH systems. I'm guessing I can go to them for everything but the airhandler.
http://jhausch.blogspot.comAdventures in Home BuildingAn online journal covering the preparation and construction of our new home.
Where in Wisconsin?
About an hour either way gets me to Milwaukee or Madison. Why do you ask?
http://jhausch.blogspot.comAdventures in Home BuildingAn online journal covering the preparation and construction of our new home.
I work in the commercial HVAC business in Madison. If you were in the vacinity, I could hook you up with a source for the unit, if you were interested.
Use a hot water coil in your air handling unit (i.e. furnace/A/C unit). Hot water coils are standard in the commercial HVAC industry. Made in all sizes that you might need. Your system isn't unusual.
At this point, I don't have anything BUT the Takagi tankless. The plan was to put in the air handler and I'm taking that into my own hands now.
http://jhausch.blogspot.comAdventures in Home BuildingAn online journal covering the preparation and construction of our new home.