Any programmable thermostats that allow timed shutoff?

[35k0]

Looking for a programmable thermostat that would allow you to have it not call for heat over a specified period of time. All I am seeing is being able to drop to 44-45 degrees.
I would like to experiment with my garage radiant setup to only run during off peak hours without me manually turning it off and on at night at morning.
Maybe this is a bad idea, but I don't need the space heated to 45-50 24/7 and am thinking this might save some $ and if I need to get it up to temp quickly I can run a propane torpedo for 20 minutes and get it up to 55-60 when needed.
Would that be too big of a setback?

R/19 walls
R/18 garage door
R38 ceiling
2'' XPS under slab, up sides of slab, 4 feet out around the building.

 

[fitter30]

Concrete floors have a lot of mass turn the heat off for x number of hours probable take the same amount of time to bring it back up to temp. A lighting timer, contacts can be wired in series with w wire can be mounted by the boiler for power and stat wire.

 

[PCustoms]

I think they all do this....

 

[PCustoms]

Edit: just checked my sensi, configured for heat only. You're right, it drops to 45 with no auto option to turn off.

I can easily click the heat to off from the app though.

 

[jlv03]

Nest thermostat can drop to 40 and have a safety temp of 35 when off. Would that be low enough?

Depending on how tight of a building you have and the off peak rate, I'd set the heat at 50-55 off peak and drop down as low as possible when on peak. Chances are you could set it at 45 during on peak and it wouldn't even turn on.

 

[35k0]

Nest thermostat can drop to 40 and have a safety temp of 35 when off. Would that be low enough?

Depending on how tight of a building you have and the off peak rate, I'd set the heat at 50-55 off peak and drop down as low as possible when on peak. Chances are you could set it at 45 during on peak and it wouldn't even turn on.

Good thought, the cheapo I have now is programmable and goes down to 44, I will try that and see what happens.

 

[yeldogt]

I think you will need a commercial thermostats ... some have a leave setting and within that there can be an off. Honeywell sells them.

That said .... I don't understand what you are trying to do. The slab is a big heat sink and you have to pick a temp. It's just too slow to respond and the cost to heat the slab. lower the input temp

 

[35k0]

I think you will need a commercial thermostats ... some have a leave setting and within that there can be an off. Honeywell sells them.

That said .... I don't understand what you are trying to do. The slab is a big heat sink and you have to pick a temp. It's just too slow to respond and the cost to heat the slab. lower the input temp

I am trying to save as much money as possible. Seeing if the slab will hold the temp well enough having the system off during peak rate times. 8am to 10pm

 

[yeldogt]

You fight the temps .. and the slab will drop too much in cold weather.

The slab will naturally require less input when the sun is out ..... you are fighting physics (nota good idea)

Lower the input and stabilize the slab. A 45 degree slab is not heating much ...

 

[35k0]

You fight the temps .. and the slab will drop too much in cold weather.

The slab will naturally require less input when the sun is out ..... you are fighting physics (nota good idea)

Lower the input and stabilize the slab. A 45 degree slab is not heating much ...

I had the thermostat set to 50
Water temp dial on the boiler panel set to 115 (tried lower and higher temps, this never affects the input/output temps)
Input/output on manifold stays around 70 in / 80 out
I have messed with the water temp dial on the boiler panel and the input/output never change.
I have the "ODR" as you stated in my other thread isn't really ODR, but it is connected as well.
I feel like the boiler is just running way too often, my power bill is huge, or maybe that is just how it is? I am new to all of this.

This is my home and garage, I don't have separate meters.



Last year, no garage heat at all.

 

[yeldogt]

Electric heat is expensive ... many many times the cost of gas. That's why people use heat pumps as they can be 1/3 to 1/4 the cost of straight electric heat depending on the equipment and the outside temps.

What you need to do is convert the energy used ... KWH in to BTU's and look at what the building requires. Thing called degree days .... it all sounds complex. It's really not -- it's what an oil company uses to estimate the oil deliveries based on the outside temp.

You can figure out what the building needs in BTU's -- and what those BTU's convert to KWH ..... read the bill to tell you what the KWH cost.

What is your KWH cost. When my one building was heated with electric (propane service being redone for the property) .... $200 was not uncommon in the dead of winter (1600sf). I was keeping it around 62 as I was not there very often ... a 4500kw heater could do it with no problem ..... but -- it was running

 

[35k0]

Electric heat is expensive ... many many times the cost of gas. That's why people use heat pumps as they can be 1/3 to 1/4 the cost of straight electric heat depending on the equipment and the outside temps.

What you need to do is convert the energy used ... KWH in to BTU's and look at what the building requires. Thing called degree days .... it all sounds complex. It's really not -- it's what an oil company uses to estimate the oil deliveries based on the outside temp.

You can figure out what the building needs in BTU's -- and what those BTU's convert to KWH ..... read the bill to tell you what the KWH cost.

What is your KWH cost. When my one building was heated with electric (propane service being redone for the property) .... $200 was not uncommon in the dead of winter (1600sf). I was keeping it around 62 as I was not there very often ... a 4500kw heater could do it with no problem ..... but -- it was running

11.48 cents per kilowatt-hour peak
About 8.48 cents off-peak

 

[Bert_]

It's not a bad idea, heat at night when your power is cheaper. The slab might store enough energy to maintain temperature through the day.

This would be easy to do with a simple timer. Just set the hours you don't want it to run.

One problem I see is that you are reducing your heating capacity by over 50%. Depends on how much heat the slab can store, your temperature in the building might vary more than you want.

 

[35k0]

It's not a bad idea, heat at night when your power is cheaper. The slab might store enough energy to maintain temperature through the day.

This would be easy to do with a simple timer. Just set the hours you don't want it to run.

One problem I see is that you are reducing your heating capacity by over 50%. Depends on how much heat the slab can store, your temperature in the building might vary more than you want.

Thanks! I am going to try it for a few days and see what happens. Might work, might be a failed experiment.

 

[PoorUB]

If you get an off peak or a night rate I can see heating only when the rates are lower or at night, but on a constant price per KWH I would set it and forget it.

I would check with the power company and perhaps they will control your heat for you and shut you down when the rate is high and back on when the lower rate kicks in. Around here they do it for everyone with dual fuel and many with floor heat.

If your rates are lower all the time after say 10PM and turn back to the higher rate at 6AM you could easily wire up a 24 hour timer to drop the call for heat during the day and heat only at night.

 

[35k0]

Was a failed experiment, the garage maintained till early afternoon then dropped to 44 by 10PM, it was -15 or colder all night and the boiler only got back to 46 as of 7am.
Will be setting to 50 and forgetting it.

 

[jlv03]

Only dropped 6 degrees over 14 hours, that's not too bad. Sounds like the bigger issue is that you can only put so much heat in the slab in the 10 hours of off peak.

Maybe try 55 overnight, 50 or 48 during the day.

I have my thermostat schedule setup so that I try to lower the temp setting during periods when I know the garage door will be open (7:45-8:15AM for leaving for school/work, around noon for returning for lunch, between 5-7PM for coming home). Otherwise opening the garage door would trigger the thermostat to kick on and try to heat, but heating isn't really necessary, just need a few minutes for temps to stabilize.

 

[35k0]

Only dropped 6 degrees over 14 hours, that's not too bad. Sounds like the bigger issue is that you can only put so much heat in the slab in the 10 hours of off peak.

Maybe try 55 overnight, 50 or 48 during the day.

I have my thermostat schedule setup so that I try to lower the temp setting during periods when I know the garage door will be open (7:45-8:15AM for leaving for school/work, around noon for returning for lunch, between 5-7PM for coming home). Otherwise opening the garage door would trigger the thermostat to kick on and try to heat, but heating isn't really necessary, just need a few minutes for temps to stabilize.

@jlv03 Good points and suggestions, thank you!

I am curious on some things.

My boiler has a temp dial on the front panel, I set it to 115
I have the taco pump set to low. (have tried other speeds, just not sure where to set things)
The water never goes above 80. The input water temp according to the manifold gauge is around 70 and the output is around 80.
The balancing valves are wide open, as are the return actuator valves.
The water temp never changes, no matter what I set the temp dial to on the front of the boiler.
The only way I can get the water temp to match the dial setting on the front of the panel, is if I choke down the return side actuator valves on the manifold.
Is this normal?

 

[jlv03]

I'm no expert on any of this stuff (outside of the controls/electrical side), so I'm probably of no help here. However, here is my basic understanding:

a) Most people aim for a 10-20 degree difference between water in vs. water out on the floor. Looks like you are right at the 10 degree mark
b) Speeding up the pump drops down that difference (Delta), vs. slowing down increases it.
c) Speeding up the pump allows for more BTUs to be pumped into the slab. Of course that also means the heat source also needs to be capable of supplying the additional BTUs.
d) On my electric boiler I just have a dial with numbers 1-10 for setting temp. I think there is a chart in the book, but I don't remember what corresponds to what. In other words, I wouldn't worry about what the dial says, I would be more concerned about is the water actually getting heated? It appears so.

 

[35k0]

I'm no expert on any of this stuff (outside of the controls/electrical side), so I'm probably of no help here. However, here is my basic understanding:

a) Most people aim for a 10-20 degree difference between water in vs. water out on the floor. Looks like you are right at the 10 degree mark
b) Speeding up the pump drops down that difference (Delta), vs. slowing down increases it.
c) Speeding up the pump allows for more BTUs to be pumped into the slab. Of course that also means the heat source also needs to be capable of supplying the additional BTUs.
d) On my electric boiler I just have a dial with numbers 1-10 for setting temp. I think there is a chart in the book, but I don't remember what corresponds to what. In other words, I wouldn't worry about what the dial says, I would be more concerned about is the water actually getting heated? It appears so.

@jlv03 That make sense, I wonder if I should experiment with increasing the pump speed?

 

[jlv03]

Sounds like you are able to heat the place, and the DELTA T is decent, so I wouldn't muck with the speed much.

 

[35k0]

Sounds like you are able to heat the place, and the DELTA T is decent, so I wouldn't muck with the speed much.

Since the outside temps dove to minus double digits this past week, it seems like it’s struggling to get to temp and hold though.

 

[35k0]

Well, i found out today that my boiler had a bad element and I had the thermostat mounted to the outside wall (inside the building of course) but the walls were staying a few degrees colder than the set temp on the thermostat so it would never get to the target temp. Bonehead move by me. I can't believe I didn't think of that.
Then we did some troubleshooting and found out one of the boiler elements was dead. New one on the way, warrantied, no questions.

So, this garage can nearly be heated by a 5kwh boiler. Should be running smooth and efficient once I get the new element installed when it arrives.

 

[PoorUB]

If your only choice is to mount the 'stat on an outside wall, make a U shaped bracket for it so air can flow all around it!

I have forced air heat in my garage but I used a thermostat that uses a remote sensor. The thermostat is mounted by the shop door and the sensor is up on the return air of the furnace. The furnace is mounted horizontally on the ceiling.

 

[35k0]

If your only choice is to mount the 'stat on an outside wall, make a U shaped bracket for it so air can flow all around it!

I have forced air heat in my garage but I used a thermostat that uses a remote sensor. The thermostat is mounted by the shop door and the sensor is up on the return air of the furnace. The furnace is mounted horizontally on the ceiling.

Thanks! I just screwed it to the side of a tall cabinet, it now sits about 2' from the wall.

 

[jlv03]

How did you find the bad element?

I installed an ammeter on the side of my boiler to see if the outdoor reset was working correctly (it is not). From what I can tell, my 6kW boiler has two elements, where it runs one element when the water is pretty warm (12A) and both most of the time (24A).

Amazon.com

 

[35k0]

How did you find the bad element?

I installed an ammeter on the side of my boiler to see if the outdoor reset was working correctly (it is not). From what I can tell, my 6kW boiler has two elements, where it runs one element when the water is pretty warm (12A) and both most of the time (24A).

Amazon.com

I had suspected it wasn't running at full capacity based on my heat loss daily adn seeing the boiler run all the time. I called Electro Industries and they had me put a clamp on meter around the power wires that connect to the elements. One had no amperage.

I wonder why the ODR isn't working for you?

 

[35k0]

Well, this was the problem, the bad element had blown open.





Shout out to Electro Industries, they overnighted me a new element no questions asked, I installed it quickly and am back up and running at full 10kwh power now.

 

[jlv03]

Is there a change in water temps in/out with the new element in place?

 

[35k0]

Is there a change in water temps in/out with the new element in place?

no, but it get the water to temp quicker. It is hard to wrap my head around but as @yeldogt and the rep from Electro explained to me, radiant only uses what it needs to put the needed BTUs into the slab and the temp dial is more of a high limit. So if the water is set to 120, it’s not going to let the water get over that temp, but the boiler is only going to heat the water to what it needs to get the necessary btus into the slab. Having two working 5kwh elements should make things more efficient for my space.