Inside programmable thermostat for owb?

[Mister Twister]

Interesting Mister Twister
1 Relay for the fan, one for the gas control and one tstat.
I may have to try that.

I have only been up and running 2 weeks now but I love my arrangement so far. Working on the heat in my garage now. Got a 12" X 24" Trane coil from work for free they were throwing it out. Not quite sure what it was for but it throws off good heat. Need to get a better blower using a house box fan for now.

 

[oneoldbanjo]

Mister Twister:

I missed the details of your system at first....then went back and read it and I now understand.....pretty cool.

And yes.....our systems can be quite different. Mine was a real pain at first.

I have a Carrier Infinity Heat pump for my house. It has a variable speed fan and a computer to help run the system as efficiently as possible. It starts with the fan running at a very slow speed, and if it can't keep up it ramps up a notch....and continues until it keeps up. My fan could not be contolled by a thermostat and fan center relay. We had to install a Zone Valve and my OWB thermostat controls the zone valve - and the zone valve bypasses the hot water from my heat exchanger in the furnace until the OWB thermostat calls for heat - then it runs the hot water through the heat exchanger. We have to turn the Heat Pump setting to run the fan on the low setting all the time as we cannot have the OWB thermostat turn it on. It actually works very well this way.....having a low speed airflow through the house at all times evens the temperature very nicely and we don't have any cold spots in the house at all.

 

[cbrslider]

I have my high limit set at approx. 145deg. on my propane water boiler inside the house. The primary loop runs through the propane boiler and then into my heat exchanger. If the OWB goes below 145deg. then the propane kicks on. I have programmable thermostats on two of my loops. It is nice to have the set back during the night and then during the day while we are away. Plus if for some reason I or the family are home during the day, just turn off the program and manually set it. Pretty easy set up for me.

Ray

 

[Mister Twister]

Mister Twister:

I missed the details of your system at first....then went back and read it and I now understand.....pretty cool.

And yes.....our systems can be quite different. Mine was a real pain at first.

I have a Carrier Infinity Heat pump for my house. It has a variable speed fan and a computer to help run the system as efficiently as possible. It starts with the fan running at a very slow speed, and if it can't keep up it ramps up a notch....and continues until it keeps up. My fan could not be contolled by a thermostat and fan center relay. We had to install a Zone Valve and my OWB thermostat controls the zone valve - and the zone valve bypasses the hot water from my heat exchanger in the furnace until the OWB thermostat calls for heat - then it runs the hot water through the heat exchanger. We have to turn the Heat Pump setting to run the fan on the low setting all the time as we cannot have the OWB thermostat turn it on. It actually works very well this way.....having a low speed airflow through the house at all times evens the temperature very nicely and we don't have any cold spots in the house at all.

Wow you have a very nice system. Carrier is made right here in Syracuse NY high end equipment. Mine is an old Lennox Pulse gas furnace. It has a spark plug in it and actually pulses like an engine also has mufflers on the intake and exhaust. It is supposed to be like 98% efficient it vents out of PVC pipe.
I have had it for approximetely 18 years and it is still going strong. It is in semi-retirement now that I have the OWB except for cooling in the summer.

 

[Mister Twister]

I have my high limit set at approx. 145deg. on my propane water boiler inside the house. The primary loop runs through the propane boiler and then into my heat exchanger. If the OWB goes below 145deg. then the propane kicks on. I have programmable thermostats on two of my loops. It is nice to have the set back during the night and then during the day while we are away. Plus if for some reason I or the family are home during the day, just turn off the program and manually set it. Pretty easy set up for me.

Ray

After having a programmable thermostat I will not be without one.

 

[oneoldbanjo]

It was my intention to let my heat pump heat our house until the weather got conistently below 40 - then use the OWB. This year I started to burn a little early as I have waaay too much wood. The Energy company came through our property and cleared our right of way and cut down about 200 trees. A lot of it was small Locust and we made fence posts....but I do have about 50 chords of wood all stacked up and ready to burn over the next 8 years or so!

Our old house had oil heat and the programmable thermostat was great. Our house was small (24x36) and well insulated. We would turn have the thermostat programmed to keep the temperature at 50 degrees when we were in bed or away, then 15 minutes before our alarm went off the oil heat would come on and warm the house to 68 degrees before we got up. The furnace would not come on at all during the night. Our new house is much bigger and has vaulted ceilings.....and it takes a long time to heat up the house if we let it cool off even with the OWB. In our new house we just let the system keep the house at 68 degrees all the time.

 

[Mogollon]

OWB Setback

I use a timer to turn off the pump on my OWB, at night between 11:30 to about 4 am and in the day between 9am and 4 pm. The indoor thermostats are programed to setback to about the same times. I've noticed a savings in fuel and longer burn times. I do have to change to longer run times when the outside temps get below -0f.

 

[bowtechmadman]

mogollan...don't you worry about your OWB overtemping if your shutting the pump down?
I also like seeing the oil guy drive by...haven't bought any in 5 yrs. I simply shut my oil boiler down unless I'll be away for more than 3 days.

 

[NC4AB]

I installed a Honeywell TH8320 programmable thermostat and have had very good luck with it. The thermostat has 3 stages of heat control, so I only had to use one thermostat.

Stage 1 = Wood Stove
Stage 2 = Heat Pump
Stage 3 = Propane Furnace

It allows for 7 day programming, and it works great after you sit down with it and mess with it a few times. Initially I played around with the "cycles per hour" setting for the wood boiler but it turned out that my wife was not used to having hot air come out of the registers.

The only thing that I have not finished is adding a relay to lock out the wood boiler when in cool mode. (for the warm days when I am still running the wood stove but the wife wants cool air during the day).

 

[Butch(OH)]

Has anyone other than me thought that somebody is realy missing the boat with this whole thermostat and control system deal for OWBs? Why hasnt some entrepreneur made up a dual thermostat that Joe average can plug and play complete with the isolation relays etc? AT least for the simple forced air system guys which has to be 50% of the total installations. I see the complications for people with dual systems like the banjo man who are adding an OWB but I dont think most are that way. You could have an injection molder make up a custom encloser, add some green and red LEDs, maybe a digital loop temp indicator and package everything up with some instructions. I wooda plunked down the cash when I installed my OWB, how about you'ens? AM I making it more simple than it can be?

 

[troy3300]

I would have paid it. I think the only problem I can see is that each brand of furnace might be controled/wired differently. The kits may have to be brand or even model specific . I still like Mister Twisters set up and that could be a universal kit.

 

[projectsho89]

I've been contemplating possible solutions to NOT installing a second thermostat (for aesthetic and operational reasons) on my in-process install.

Set up is a Heil 90+ LP gas furnace, single zone and an OWB with plenum-mounted HX. Controlled by a conventionally wired 4-wire programmable electronic thermostat. The OWB circulator will be set to run continuously.

My idea was to be able to maintain the LP furnace control as already implemented whenever the OWB was in a "not ready" ie, cold (below 120-140F) condition. Whenever the OWB is "ready", the call for heat from the thermostat is intercepted and translated into a "blower on"-only call.

I think I can easily achieve this with a simple upper thermostat (SPDT) from a hot water heater such as a White-Rodgers 756-1. Mount the 756-1 to the HX on the outside of the plenum in the immediate vicinity of the HX so it can detect and react to the temperature of the HX. The 756-1 is adjustable from 90-150F.

From the thermostat wire input to the furnace, three wires would be run to the location of the 756-1 thermostat.

Disconnect the white wire from the furnace input terminal and connect it to the Common (#1) terminal of the 756-1, the NC (#2) terminal of the 756-1 gets run back the furnace's white terminal from which the wire was previously removed. The NO (#3) terminal on the 756-1 is run back the furnace's terminal block and is piggybacked onto the green wire connection.

I think I can adjust the setting to around 120-140 and get it to fall-back to normal gas operation when the OWB's output is below the set point. I'll probably have to play with it to see if I can get it right.

My fallback plan is to use a strap-on SPDT aquastat on the inlet supply line. Since they cost around USD 60-80, I think I'll give the $15 part a test drive (of course, it would help if I actually had an OWB on hand....)

Comments?

Steve

 

[Mister Twister]

I've been contemplating possible solutions to NOT installing a second thermostat (for aesthetic and operational reasons) on my in-process install.

Set up is a Heil 90+ LP gas furnace, single zone and an OWB with plenum-mounted HX. Controlled by a conventionally wired 4-wire programmable electronic thermostat. The OWB circulator will be set to run continuously.

My idea was to be able to maintain the LP furnace control as already implemented whenever the OWB was in a "not ready" ie, cold (below 120-140F) condition. Whenever the OWB is "ready", the call for heat from the thermostat is intercepted and translated into a "blower on"-only call.

I think I can easily achieve this with a simple upper thermostat (SPDT) from a hot water heater such as a White-Rodgers 756-1. Mount the 756-1 to the HX on the outside of the plenum in the immediate vicinity of the HX so it can detect and react to the temperature of the HX. The 756-1 is adjustable from 90-150F.

From the thermostat wire input to the furnace, three wires would be run to the location of the 756-1 thermostat.

Disconnect the white wire from the furnace input terminal and connect it to the Common (#1) terminal of the 756-1, the NC (#2) terminal of the 756-1 gets run back the furnace's white terminal from which the wire was previously removed. The NO (#3) terminal on the 756-1 is run back the furnace's terminal block and is piggybacked onto the green wire connection.

I think I can adjust the setting to around 120-140 and get it to fall-back to normal gas operation when the OWB's output is below the set point. I'll probably have to play with it to see if I can get it right.

My fallback plan is to use a strap-on SPDT aquastat on the inlet supply line. Since they cost around USD 60-80, I think I'll give the $15 part a test drive (of course, it would help if I actually had an OWB on hand....)

Comments?

Steve
Steve

I think your on the right track. I used a unit from LOWES not sure what brand it was for a lower hot water heater element so it is a simple snap disc thermostat adjustable from 90-140 deg. it works fine so far. I have it laying next to my Hx in the plenum need to mount it yet. Tested it numerous times already and have been up and running now for 2 - weeks. I just had to use a relay to bypass my fan control and one to inhibit the gas valve circuitry. Good luck it is not that hard.

 

[projectsho89]

I think your on the right track. I used a unit from LOWES not sure what brand it was for a lower hot water heater element so it is a simple snap disc thermostat adjustable from 90-140 deg. it works fine so far. I have it laying next to my Hx in the plenum need to mount it yet. Tested it numerous times already and have been up and running now for 2 - weeks. I just had to use a relay to bypass my fan control and one to inhibit the gas valve circuitry. Good luck it is not that hard.

Yeah, I saw your post and thought the same result could be achieved much more simply which is why I came up with this idea.

That's why I intercepted the call for heat and either pass it unchanged or redirect it to a "blower only" request.

Steve

 

[NC4AB]

My Hardy OWB came with a low temperature cut off temperature switch (Grainger # 2E245 ~ $9.75). It is mounted on the OWB and you loop the control wire for the circulator pump through it, if the water temperature drops below 90 F it opens up and the circulator cuts off.

Since I was using a 3 stage thermostat this keeps from heating the OWB with the heat pump / gas furnace if the fire goes out.

The picture below is an early version of my data logger for the wood stove, which will provide some historical data to see if I really am saving any wood by using the programmable thermostat: