HEATPUMP/OWB HELP!

[Kubota king]

Does anyone have a owb with a heatpump/ac set up? Most heatpump have heat strips to help them along when temps drip below freezing. My problem is I can't find any schimatics on how to wire my owb as my primary heat and allow the heatpump and strips be my auxiliary heat. As of now it looks like I'd need 2 separate thermostats to run this set up and would require me to manually switch from one source to another. Anyone ever setup a system like this to all work in conjunction properly?! Please help! Thanks in advance!

 

[Sandhill Crane]

I'm not sure I understand your question, or why would you need to manually switch from one to the other? Isn't that what the thermostat(s) would do? Wouldn't running the owb idle the heat pump on its own(two separate systems), and the heat pump would kick in if the boiler cools down, say you were gone for say several days. I see the owb as a manual system, and the heat pump as an automatic system. Why connect them?

I do not have an owb. We do have a 'ground source' heat pump/ac (with a built in 50 amp electrical heat mode if the water fails to circulate), and wood stove. I'm guessing we set the thermostat at 70, and the fan function to circulate full time in the winter pushing/pulling air through the return air and duct system. If the wood stove is burning, the heat pump does not come on, but its fan is circulating air. When the wood stove is out and the temp drops below 70 degrees, the heat pump kicks in.
In the summer we manually change the thermostat to 78 degrees and manually switch the Mode function from Heat to Cool, and ac comes on when the house is above 78.

There are three 'manual' temperature related setting on the thermostat. Changing the Mode on the thermostat to Heat, Cool, or Emergency Heat (electrical heat), and the fan Mode to on/off. In the Off mode the fan cycles on/off several times per hour. In the On mode it runs continuously. If there is a failure in the Heat Mode system then the Emergency Heat(electric heat) automatically kicks in.

Our system components are the house well (with submersible pump); two large bladder tanks (water storage for fewer submersible pump cycling, and longer run times), heat pump, electric hot water heater. The heat pump has three separate systems. The water circulating system, the refrigerant and compressor, and the back-up electric heat system.
EDIT: The fourth system would be air circulating system.

An air/air heat pump may operate differently.

Ah! Your running the same fan for the heat pump and owb to circulate air through the duct work? And if run continuous, then it would get too hot in the house using the owb?

 

[Kubota king]

Your basically on to what I'm saying but the problem is I DON'T want to have to switch them manually. If as you say I'm gone for 5 days the stove runs out of warm water not satisfying the thermo but the pump contines to pump cold water thru my coil and calls for fan to run the whole time. And then the heatpump thermo would call for heat and blow air thru my cold owb coil lowering efficiency. Plus constantly calling for airhandler fan. Does that make sense? The perfect setup in my mind would be 3 stages of heat. 1 my owb if it fails it doesn't cyclear it's pump or call for airhandler fan. Temp drops 4 degrees in house and 2nd stage kicks in with heat pump satisfying thermo. Unless it's below freezing at which point my 3rd stage or auxiliary electric heat strips would also kick in to assist the heatpump and not overworking it. As they are only efficient down to freezing or slightly below. I live in wv heart of Appalachia. Make sense or am I just dreaming lol thanks!

 

[StihlKicking]

My OWB is wired so that when I move my Thermostat switch to AUX my boiler heats the house not the strips. If I don't want to use the boiler I can move the switch to heat. On this setting the heat pump runs with the strips kicking in if the pump can't keep up or fails.


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[StihlKicking]

FYI the AUX setting is the emergency heat on my thermostat. You don't need two thermostats, just wire the thermostat wire from your boiler to the emergency heat relay on your unit then disconnect the heat strips from that relay. The emergency setting is really unnecessary anyway since the strips will automatically kick on in the normal heat setting if there is a problem with your pump.


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[Kubota king]

Ok,that is starting to make sense but with that setup Can your owb fail and the heatpump save the day? I am apparently going Bout it backwards in thinking that my owb MUST be wired as the primary?
And in your setup it isn't ?

 

[Kubota king]

Thimk it'd be possible to get a schimatic? My main thermostat is a Honeywell pro 500

 

[StihlKicking]

Ok,that is starting to make sense but with that setup Can your owb fail and the heatpump save the day? I am apparently going Bout it backwards in thinking that my owb MUST be wired as the primary?
And in your setup it isn't ?

No my owb is wired to my emergency heat or secondary. When wired this way you can flip the switch back to heat and the heat pump will save the day if your OWB fails. The relays you want to get at are in the back of your central unit not located in the actual thermostat box. All your doing is wiring up a relay that is controlled by the thermostat In your house. When a certain temperature is reached it will break the circuit and cause you fan to blow and the pump on your OWB to start circulating.


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[StihlKicking]

Here are some pictures of my thermostat and the schematics for wiring my boiler to the unit. What brand of boiler do you have?

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[Kubota king]

Thanks bud! This should be helpful! I have a Mahoning 300.

 

[Kubota king]

Stihl does your configuration require you to be around when the owb would fail to manually switch over to HEAT to allow your heatpump to take over as normal or can you be gone and the owb would fail and heatpump automatically comes on without having to manually switch your thermostat? Seems like I'm not able to get away from the step of me having to change from one stage (owb) to another (hestpump with strips).

 

[StihlKicking]

Stihl does your configuration require you to be around when the owb would fail to manually switch over to HEAT to allow your heatpump to take over as normal or can you be gone and the owb would fail and heatpump automatically comes on without having to manually switch your thermostat? Seems like I'm not able to get away from the step of me having to change from one stage (owb) to another (hestpump with strips).

Yes I have to physically flip the switch to go from OWB to heat pump if necessary. Which isn't a big deal in my situation. If you feel like you need the heat pump to automatically back up the boiler you could wire the boiler to the primary heat relay and switch the heat pump over to secondary. If I'm going to be gone for several days I just flip my switch back to the heat pump and let the boiler burn out, same if there is a problem with the boiler that needs addressing. If something were to happen to the boiler when I'm at work or asleep it doesn't get cold enough here to freeze anything before I could take notice and flip my switch. FYI my boiler rarely fails and by rarely I mean pretty much never.


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[Kubota king]

Ok that's what I was thinking and yes I know the feeling they are pretty simple setups so not much to worry about! Thanks so much for you help!

 

[GF#2]

What you want to do would be pretty simple for a qualified HVAC tech. You could wire the boiler as the first stage of heat and the heat pump for the second stage and the electric heat for third stage heat. This would probably require a different tstat and because the heat pump would be stage two the O terminal on the tstat would not control the reversal valve in the heat pump properly. But someone with a good understanding of HVAC controls could ad a relay to make it function properly. Your HVAC service company could most likely set this up.

 

[kingOFgEEEks]

Just thinking laterally here - what's wrong with having 2 thermostats? In my house, I have a thermostat for the wood heat, and a second one for the oil backup. I just make sure to set the oil backup to a couple degrees cooler than the wood heat, and it never runs unless the fire goes out. For example, I will set the wood heat thermostat to 70, and the oil heat thermostat to 65, and unless the wood fire burns out, the oil burner never kicks on. It's completely automatic, and dead simple to know which source is running.

 

[Kubota king]

My hvac guy and the supply house is both working on it and have said same thing it may be possible with some tricky relaying work and possible with a 3 or 4 stage tstat but definitely trickey. I thimk it's crazy thatnothing like this has been invented yet.

 

[Kubota king]

King there's nothing wrong with 2 tstat except thst when the wood heat fails or goes out there's nothing to turn it off when the 2nd tstat calls for heat meaning if the fire just went out the pump would continiously pump cold water thru the deck and call for the fan to run constantly due to not being able to satisfy it's tstat. And then while all this is happening the 2nd tstat would be running the heatpump and electric hest blowing air thru the cold deck of owb wasting heat bad. And then when and If it did satisfy it'd tstat when it kicked off the fan would still be running and the owb pump would still be circulating cold water....

 

[Kubota king]

Its not so complicated to get the hest pump to back up the owb automatically or even the electric heatto back owb up if it would fail but getting the heatpump to back up the owb and bring in the electric heat strips to accommodate the heat pump the way they are designed to work proves to be very difficult...

 

[kingOFgEEEks]

King there's nothing wrong with 2 tstat except thst when the wood heat fails or goes out there's nothing to turn it off when the 2nd tstat calls for heat meaning if the fire just went out the pump would continiously pump cold water thru the deck and call for the fan to run constantly due to not being able to satisfy it's tstat. And then while all this is happening the 2nd tstat would be running the heatpump and electric hest blowing air thru the cold deck of owb wasting heat bad. And then when and If it did satisfy it'd tstat when it kicked off the fan would still be running and the owb pump would still be circulating cold water....

Makes sense. My forced air furnace has a limit switch, so when the firebox isn't warm enough to run the blower, it won't come on, no matter what the thermostat is calling for. All the thermostat does is open the draft. I wonder if it would be easier to set up with a limit switch for the pumps - if the water isn't warmer coming out of the OWB than it was going in, it wouldn't run.

 

[Kubota king]

My owb is somewhat self contained only comms with house tstat is turn in pump and turn on air handler fan. Then off on both once satisfied if fire goes out in box tstat has no way of knowing owb is cold... it's a tricky thing for sure!