Water To Air Heat Exchanger Questions

Water To Air Heat Exchanger Questions

PostBy: j3pup On: Sat Nov 12, 2011 1:34 am

I am about to install an EFM 520 in my 5 year old house (2500sq feet for this application). The house currently has an air to air heat pump and the associated ductwork. I would like to install radiators/baseboard but the wife doesn't like the look of baseboard, so I am stuck going with an water to air heat exchanger for my main living spaces. My question is how do I install the water to air heat exchanger in the existing ductwork, and then regulate the temperature? Here are my questions...

1. How do you force air over the exchanger without running the air to air heat pump? Can I wire up the thermostat to just turn on and off the fan?
2. If I am correct with step 1, do you also turn on the circulator pump at the same time?
3. Is what I am trying to do a total mistake?
4. Do I pull the exchanger out for the summer, when my heat pump becomes my air conditioning?
5. Do I have to worry about burning up my fan, forcing air over the exchanger?
6. Am I totally wrong and I should have a whole seperate fan/exchanger assembly for this?
7. Is this as efficient as having baseboard?


P.S. I will have radiators in my garage and basement, she doesn't get any say over that!

Re: Water To Air Heat Exchanger Questions

PostBy: WNY On: Sat Nov 12, 2011 8:33 am

Use the SEARCH on here, there are a few others that are using this setup. A lot of good discussions and pictures available.

h2o-air heat exchanger installation

Water to Air Heat Exchanger

Water to air heat exchanger coil???
Hot Air Coal Stoker Stove: Keystoker 90K, Leisure Line Hyfire I
Coal Size/Type: Rice
Stove/Furnace Make: Keystoker, LL & CoalTrol
Stove/Furnace Model: 90K, Hyfire I, VF3000 Soon

Re: Water To Air Heat Exchanger Questions

PostBy: coalkirk On: Sat Nov 12, 2011 9:56 am

I don't have a heat pump, just an A/C system so I'm not sure of the best way to do it. Maybe have it wired as the emergnecy heat and shut off the breakers for those heaters. Yes you want to turn on the circulator at the same time. A 24 volt relay will do the job. You don't need to take the heat exchanger out for summer but it is nice to be able to do so. I take mine out every two years to clean it. Even though a filter is installed ahead of it, fine pieces of dust and dirt still get to it. I pressure wash it.
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I also got a coil that is larger than the duct and had transitions made to lessen the "restriction" and make it easier on the fan.
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It's a comfortable way to heat but I would say it's not quite as comfortable as radiators or baseboards. It will beat the heck out of a heat pump though.
Stoker Coal Boiler: 1981 EFM DF520
Coal Size/Type: anthracite/rice coal

Re: Water To Air Heat Exchanger Questions

PostBy: dave brode On: Sat Nov 12, 2011 12:04 pm

You can use an aquastat to lock the compressor out. That way, you can leave the heat pump on and the crankcase heater will still run so the heat pump will still be ready to run if you need it. I called York and a guy there told me which wire to "break" with the stat. I set the aquastat so the compressor is locked out at 120* water temp. If the fire dies, the heat pump comes back to life. There coil will not hurt a thing in your cooling season, but it will sweat if you don't wrap it.

The thermostat for my heat pump cycles the fan as it would normally. No extra thermostat needed. I run my circ pump 24/7, as the piping is in conditioned area, no wasted heat. No pump controls, very simple. With your radiators in basement, this may not work for you, unless you use controls to run the pump anytime any of your zones needs heat, use zone valves, etc, etc.

I also use a 2nd aquastat to allow turning the heat pump's fan on to act as an add'l dump zone. [my basement fan coil unit is primary dump zone]

Note, if you leave the heat pump on, with just the compressor locked out, the toaster will still run if you move the thermostat too far at one time.

1st pic is 30x15" coil in house's heat pump duct, showing clamp on 'stats. 2nd pic is basement fan/coil [homemade box with 12 x 12" coil in top, filter rack in bottom, and an old house furnace squirlcage] It does have duct connected to it now.

Fwiw, some guys love baseboard. I like air over water, and I would not trade my system for baseboard, even at equal cost. A $200 coil and some pipe = done. You can humidify air easily. Note the total water loss humidifier on the house duct. It works VERY well. No slime growing, just change the $15 water grid each year. Remove it for summer, put a new one in each fall.

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dave brode
Stoker Coal Boiler: Keystoker KAA-2
Hand Fed Coal Boiler: used to have a 5 section Red Square
Coal Size/Type: rice anthracite

Re: Water To Air Heat Exchanger Questions

PostBy: j3pup On: Sun Nov 13, 2011 9:38 pm

Thank you all so much this answers all my questions and a few I haven't thought of!