Programmable Thermostat with Ramp

OK sorry, I went back and that was Win's post about oil furnace not yours.

You have said several times you want the aux heat to come on "when it's needed" What is your criteria for when it's needed.

AH, I did find this,

Most heat pump systems are designed to automatically switch to AUX heat when the indoor temperature is 3 degrees colder than the thermostat setting.

more than 3 degrees (it?s 6 degrees in this scenario), the system will automatically turn on the AUX heat to help your home meet the desired temperature faster.

So first, check to see if your thermostat only says AUX when you raise the thermostat 3 degrees or higher than the current temperature of your home. If so, that?s normal. But here?s the problem: it?s still expensive. So, if you want to cut down on your energy bills, try

Mikek

e. How is that relevant?

ill also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry w ith deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) tempera ture dropped too far the second bulb switch would close and the backup heat would come on.

h ramps the temperature up slowly enough to not kick in the backup heat.

sk your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "ins taller", like I was not worthy of information.

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n dig up a manual. I have no other way of knowing what the thermostat will do, but I can assure you that there is not a special output for "high diff erential temperature". There is a signal to turn on the heat pump and a si gnal to run the electric coils. The furnace may or may not cut off the hea t pump when the coils are on regardless of what the thermostat does.

ineer my heating system. Originally I was asking if anyone knew about a th ermostat that would ramp up the temperature in a way that would not trigger the back up heat.

e measurements. I've not done that because it doesn't change the solution. The backup is coming on either because the temperature is too far from th e set point, or because the heat has been running too long. The former can only be from the thermostat, the latter could be implemented in either.

n the various components to see exactly when what runs. I don't plan to ei ther. Not useful info.

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And the light bulb finally comes on. Now you fully understand the problem I am trying to deal with.

I know how heat pumps are intended to operate. They use aux heat for some or all of these things depending on the maker.

1) Outside temp below some setting. 2) Inside temp below set point by some amount. 3) Thermostat calls for heat but still not up to temp after some time. 4) Defrosting outside coils. 5) Some reason I'm not recalling at this moment.

When the program setting turns the heat back up either reason 2 or 3 may re sult in the aux heat coming on. I don't want that. Once it reaches the ne w set point it should then continue operating as it did before.

My intent in this thread is to figure out if there is a thermostat that man ages the set point in a way that reason 2 and 3 are not invoked. I'm reall y not trying to redesign a thermostat. That would be my last resort and li kely would not do it even then.

This shows labeling for all the wires that are connected in my furnace. Y turns on the compressor, so rather than being for cooling it turns on the h eat on a heat pump and W turns on the aux heat.

There is no outdoor thermometer connected to the thermostat, so it can't do anything based on outdoor temperatures.

So that should finally answer everyone's questions. I'd still like to find a thermostat that lets me not have this problem when turning the heat back on for ToU.

--

  Rick C. 

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Before you get to flippant with your comments, this was my very first post.

" My thinking is, the thermostat sees a high delta between the house temperature and the set temperature. In order to correct that (for your comfort) it turns on both heat pump and auxiliary heat." I'm done. Mikek

t.

I don't know why you are ticked. It has been mentioned many times that the aux heat may kick in for several different reasons. That is not my concer n and it never has been. I'm not trying to reverse engineer the thermostat . It has never been about that as I've said any number of times.

I just wanted to ask if anyone knew of a thermostat that properly adjusts t he set temperature so as to NOT turn on the aux heat. But everyone ignores my request. From the first post, "I'm wondering if anyone makes a program mable thermostat that deals with this issue."

Anyway, seems the answer is, "No, no one knows anything about a thermostat that won't trigger the aux heat when bringing up the set temp five degrees" .

Sorry you are upset. Thanks anyway.

--

  Rick C. 

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  -+-+ Tesla referral code - https://ts.la/richard11209

Ok, one more, I don't know your Tou schedule so I'm just picking times. Does your existing thermostat have enough programmable times to allow you to say Turn on at 6am and warm the house to 64* then at 7am warm the house to 67*, then at 8am warm the house to 70*. Might not take an hour to warm the house 3*. Or if your delta is 3* to cause aux to work, them make the difference

2*, 63*, 65*, 67*, and 69* over what ever period of time it takes to warm the house 2* each run. No, I don't know of a thermostat that will solve you problem Mikek

If you had one temperature where you would want the Aux to run, say 60 degrees. You could put a Mechanical 60 degree 'open on temp rise' switch in the thermometer wire that tells the control board to turn on the aux heat. That way the aux would never run unless the house temp was below 60 degrees. I have no clue if that works for you because you never gave me a good answer to, When do you want the aux heat to run?

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the aux heat may kick in for several different reasons. That is not my co ncern and it never has been. I'm not trying to reverse engineer the thermo stat. It has never been about that as I've said any number of times.

ts the set temperature so as to NOT turn on the aux heat. But everyone ign ores my request. From the first post, "I'm wondering if anyone makes a pro grammable thermostat that deals with this issue."

tat that won't trigger the aux heat when bringing up the set temp five degr ees".

No, I covered that in another message. There are a total of four settings a day and that is needed to cover the two setback time periods each day in the winter. Off at 6AM, on again at 9AM, off at 5PM on again at 8 PM.

I don't think can just turn off the aux heat with a relay. In my other hou se with oil heat it turns off the heat pump when running the aux heat. So when the oil burner didn't come on the house would have no heat at all! Ma ybe this house does or doesn't do that, I can't say. But I'm not really lo oking for such an invasive solution. I'd have to tap into the wires from t he thermostat inside the furnace and I'm not keen on doing something like t hat.

Someone I know had a furnace installed and they had to return at some point to repair something. The next day the furnace caught fire and the house b urned down. I don't want anyone pointing fingers at my invasive approach i f something happened. I say that, but I did install my own humidifier. No t much difference except it doesn't connect to the furnace wiring. They ac tually use a pressure switch to sense the differential pressure between the plenum and the cold air return. The first one was bad and being an afterm arket kit, they sent me a whole other kit!!! lol

I'm ready to drop this. It's only an issue on the colder days and it's jus t the one hour when it has to come up to temperature. My utility provides consumption data by the hour and alerts. I have it set for an alert when h ourly consumption is over 10 kWh. Unless the aux heat runs the whole hour it's hard to get that high.

It looks like it is not uncommon to use about a dollars worth (12 kWh) of e lectricity in those hours, but not every time for sure. It is hard to tell if this is more electricity than it would have used in the off period as t he usage is often well below a third of this prior to the off period. The usage seems to be very uneven at best, so it's hard to speculate.

I am sure this is saving money for both me and the utility though. By not using the electricity during the peak times the rates are lower by 5x in th e winter and 10x in the summer. The utility can sometimes pay an equally l arge peak rate in the summer. The marginal electric rates can be HUGE!

Given that the temperature doesn't dip so much when the system is off, it w ould definitely be practical for most to be on ToU and cut their heat at th ose times. I house I'm looking at buying is a very old stone structure bui lt before the battle of Gettysburg. When the price of oil went up to $4 a gal, they installed straight electric heaters with bricks inside. The bric ks keep enough heat that the utility cuts off the heat at peak times and th ey charge a much lower rate. It ends up being pretty practical.

I want the aux heat to run when the house can't be kept warm by the heat pu mp alone. That has little to do with the problem with the setback returnin g to the normal temperature.

--

  Rick C. 

  -++- Get 1,000 miles of free Supercharging 
  -++- Tesla referral code - https://ts.la/richard11209

t post.

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at the aux heat may kick in for several different reasons. That is not my concern and it never has been. I'm not trying to reverse engineer the ther mostat. It has never been about that as I've said any number of times.

usts the set temperature so as to NOT turn on the aux heat. But everyone i gnores my request. From the first post, "I'm wondering if anyone makes a p rogrammable thermostat that deals with this issue."

ostat that won't trigger the aux heat when bringing up the set temp five de grees".

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s a day and that is needed to cover the two setback time periods each day i n the winter. Off at 6AM, on again at 9AM, off at 5PM on again at 8 PM.

Simple solution, don't bother setting it back. How many days a year does a house with a heat pump system drop enough in just 3 hours to make it worthwhile to set it back? Heat pumps, at least air based ones which are 99% of the ones out there, are typically in moderate climates. If it's 25F outside and I turn off my furnace, it only drops maybe 2 deg in 3 hours. Not much point. All you're saving is the heat loss due to the house being at 68F instead of 70F. So over 3 hours, the average is 69F. The heat loss is largely a function of the temp difference. So with the temp at 70F, your delta is 70-25out = 45. With it averaging one degree lower, you're at 69-25 = 44 delta. Very little difference. If you set it back for eight hours overnight, then you could see it drop 6 deg, averaging 3 deg for 8 hours which is more significant. And if you're some where that it's cold much of the time, an air heat pump isn't a good solution. I've said before that from what I've seen, most heat pump systems are not set back, even overnight because if you do so, to get it warmed up again in the morning frequently requires aux electric heat and that costs a lot of money.

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s r

Yeah, you keep saying that, coming up with all kinds of bizarre claims, like house electric service could not support aux heat and the heat pump at the same time, but all the evidence, like the manual for your thermostat says otherwise. You could just turn it off with a switch.

he aux heat.

It's also possible that some incompetent installer didn't know WTF they were doing. Would not be the first time. I mean it's incredibly stupid to turn off the heat pump, unless it's too cold outside. Turning it off does two things:

1 - Greatly increases the amount of time to raise the temp 2 - Substitutes using electric energy with resistance heat for all the heating, instead of the heat pump which gets 4X more heat for the same $$. Or using fuel oil, which is probably more expensive too, if it's oil.

l! Maybe this house does or doesn't do that, I can't say.

Geez, you never turned the heat up several degrees and noticed what happens ? Just turn it up 5 deg, that will trigger aux heat. Then either the compres sor is running and making noise or it's not.

Also, your thermostat is obviously made by Honeywell, it looks like and the programming is the same as their VisionPro series. The VP series has an INDICATOR on the display, which shows when aux heat is turned on. If Trane hosed you and yours doesn't and you have a common connection at the thermostat, you can easily put an led on it to see what's going on.

p into the wires from the thermostat inside the furnace and I'm not keen on doing something like that.

Nonsense. The thermostat calls for heat, it calls for aux heat. RTFM

nt to repair something. The next day the furnace caught fire and the house burned down. I don't want anyone pointing fingers at my invasive approach if something happened.

Yeah, figured that was coming. Just give up and call the Trane service people.

I say that, but I did install my own humidifier. Not much difference exce pt it doesn't connect to the furnace wiring. They actually use a pressure switch to sense the differential pressure between the plenum and the cold a ir return. The first one was bad and being an aftermarket kit, they sent m e a whole other kit!!! lol

ust the one hour when it has to come up to temperature. My utility provide s consumption data by the hour and alerts. I have it set for an alert when hourly consumption is over 10 kWh. Unless the aux heat runs the whole hou r it's hard to get that high.

electricity in those hours, but not every time for sure. It is hard to te ll if this is more electricity than it would have used in the off period as the usage is often well below a third of this prior to the off period. Th e usage seems to be very uneven at best, so it's hard to speculate.

t using the electricity during the peak times the rates are lower by 5x in the winter and 10x in the summer. The utility can sometimes pay an equally large peak rate in the summer. The marginal electric rates can be HUGE!

Well, duh! Exactly what I said above. Then there is little point to settin g it back to begin with.

it would definitely be practical for most to be on ToU and cut their heat at those times. I house I'm looking at buying is a very old stone structur e built before the battle of Gettysburg. When the price of oil went up to $4 a gal, they installed straight electric heaters with bricks inside. The bricks keep enough heat that the utility cuts off the heat at peak times a nd they charge a much lower rate. It ends up being pretty practical.

pump alone. That has little to do with the problem with the setback return ing to the normal temperature.

It has everything to do with returning back to the normal temperature, because that is what triggers the aux heat that you're complaining about. It will invoke aux heat under two conditions:

1 - It can't maintain the set temp with just the heat pump because it's too cold outside or so cold that the heat pump is locked out. 2 - The set temp is raised more than a couple degrees, so it turns it on to get you to the new temp quicker than without aux heat.

Your problems is #2. When you set it back, you introduce the possibility of #2, if the temp drops more than one or two degrees.

Also, your thermostat has program variable #0680, which sets how aggressiv e it manages heat mode.

'Applies to recovery ramp and use of auxiliary heat during recovery.

1?less aggressive temperature control (could cause temperature undershoot)

2 -standard

3?more aggressive temperature control (could cause temperature overshoot)

They don't spell it out beyond that, but it sounds like if you selected

1, it might not be as aggressive turning on aux heat. Easy to try.

But heh, better to rant about what can't be done.