RC1000 EM heat works, but not normal 2nd stage heat

[wmcneil]

I have two HAI Omnistat RC1000 thermostats that are both just under 1 year old, and both are behaving as follows:

system type is set to heat pump (NOT dual fuel)
stage settings are 2 stage heat and 1 stage cool
Hold is set to on (defeats EEC settings)
Mode is set to heat

When I raise the heat setpoint 3 degrees or more above the current temperature, only the first stage heat indicator comes on. The 2nd stage heat indicator is not on, and I have verified the W2 output is at 0V. (The 1st stage heat indicator is on, and the Y1 output is correctly at 24V)

If I change the Mode to EM Heat, then the second stage heat indicator comes on, and I have verified the W2 output is at 24V. (The 1st stage heat indicator is off, and the Y1 output is correctly at 0V)
 
Since both thermostats are behaving the same way, perhaps I have overlooked a setting somewhere, but I have scrubbed through everything and can't find anything wrong.

 

[wmcneil]

Posting a follow-up message, as this may help someone else. It turned out that both thermostats were in fact not functioning correctly, as neither one would ever turn on the second stage heat, unless the thermostat was placed in emergency heat mode. It took quite a few rounds with HAI tech support to run various tests, and I had to push a little, but in the end they shipped me two new thermostats, and that solved the problem. The thermostats were originally purchased on buy.com, and were advertised as new.
 
One key point that might help someone else who is trying to test the thermostat for correct 1st stage and 2nd stage heating operation: If you are using the thermostat in heat pump mode: If you change the hold mode to ON and mode to Heat, it overrides the EEC Heat, and EEC Start Delay settings, such that raising the heat set point one degree above the current temperature is sufficient to engage 1st stage heat, and after 1 minute subsequently raising the heat set point to EEC Aux Heat Differential degrees above the current temperature is sufficient to also engage 2nd stage heat.  It is not clear why HAI chose to have hold mode set to ON not also override the EEC Aux Heat Differential setting, but my experience has been that it does not override it.

 

[wmcneil]

Further clarifications that might someone else out:
 
When the RC1000 has system type set to heat pump, hold is on, and mode is heat, the EEC Aux Heat Differential is in fact overridden. Per the HAI documentation, if the heat set point is >= 1 degree over the current temperature, 1st stage heat is activated. If the heat set point is >= 3 degrees over the current temperature, 2nd stage heat is activated.
 
My replacement thermostats behave as described above. Unfortunately, when hold is off, the thermostats are still behaving as if EEC Aux Heat Differential is overridden to a value of 3, despite the fact that I have it set to 1. So this means the thermostat will never turn on second stage heat unless the heat set point is >= 3 degrees over the current temperature. So when it is around freezing or colder outside, and the thermostat is set at 68, and the actual temperature drops to 67, the thermostat turns on 1st stage heat, and never turns on second stage heat, even after the rate of heat increase and minumum run time criteria are met. So the room temperature is not able to be maintained, 
and the heat pump runs continuously. I know this is how the thermostat is behaving because I have gotten up more than once in the middle of the night after realizing the heat pump has been running a long time (it is outside the bedroom), and only when I raise the heat set point to >=  3 degrees over the current temperature does the second stage heat turns on.
 
I have spent a great deal of time trying to get answers from HAI tech support, and I am loosing my patience. It seems the advanced features of these devices do not work as advertised.....If I ever get a complete answer from HAI, or figure it out on my own, I will post back here.

 

[fcwilt]

From reading the installation manual I don't think the EEC setting is a temp differential. It appears to be just a setting (from 1 to 10) that can be used to "fine tune" the behavior of the ECC feature.
 
It also states that under certain circumstances, when using EEC, the heat pump will run continuously and the aux heat will be cycled on/off.
 
Is that what you are seeing?

 

[ano]

I haven't verified this, but I also seem to have read that if you turn EEC off (set it to zero) then with the termostat NOT in hold, it should obey the temp diff or the time value.  From what I have heard, EEC is the secret HAI special sauce that prevents second stage at all cost. In addition, HAI has given the impression that it "learns" so it may act one way one day and another way another day. 
 
In any case, I really wish HAI would be straight forward on exactly how these things work,  Tech people buy these, and we automate them and to do so we need to understand exactly how they work.  I am still seeing lots of strangeness with these. For some unknown reasons, the RC-1000 seems to act stranger than the RC-2000.  When you spend $300 for a thermostat, it is your right to know exactly how it works.

 

[wmcneil]

From reading the installation manual I don't think the EEC setting is a temp differential. It appears to be just a setting (from 1 to 10) that can be used to "fine tune" the behavior of the ECC feature.
 
It also states that under certain circumstances, when using EEC, the heat pump will run continuously and the aux heat will be cycled on/off.
 
Is that what you are seeing?

 
There are four settings that are grouped under the heading of "EEC Settings" in the installation manual. Heat EEC and Cool EEC are rate-of-temperature change settings, Aux Heat Differential is a difference between current temperature and heat set point temperature, and Start Delay is minimum run time for stage 1 heat. In order for 2nd stage heat to be activated, all three criteria must be met when the system type is Heat Pump and Hold is off. (Cool EEC does not apply to heat mode)
 
I am not seeing 2nd stage heat cycle on and off. I am seeing 2nd stage heat never be turned on, regardless of the Aux Heat Differential and Heat EEC settings, unless the heat set point temperature is >= current temperature + 3.  I know the Start Delay is being satisfied, because I have it set to 1 minute. I know the Heat EEC setting is being satisfied, because I have it set to 7 degrees per hour, and I am seeing the 1st stage heat run for 10-20 minutes and not raise the temperature by even one degree. (This is when it is near freezing temperatures outside)

 

[wmcneil]

I haven't verified this, but I also seem to have read that if you turn EEC off (set it to zero) then with the termostat NOT in hold, it should obey the temp diff or the time value.  From what I have heard, EEC is the secret HAI special sauce that prevents second stage at all cost. In addition, HAI has given the impression that it "learns" so it may act one way one day and another way another day. 
 
In any case, I really wish HAI would be straight forward on exactly how these things work,  Tech people buy these, and we automate them and to do so we need to understand exactly how they work.  I am still seeing lots of strangeness with these. For some unknown reasons, the RC-1000 seems to act stranger than the RC-2000.  When you spend $300 for a thermostat, it is your right to know exactly how it works.

I want the Heat EEC setting to work as advertised, which means if the rate of heat increase is < the EEC setting, and the other criteria(Aux Heat Differential and Start Delay) are met, 2nd stage heat turns on. I do not want to control the 2nd stage heat based solely on Aux Heat Differential and Start Delay, because the whole reason I bought these very expensive thermostats was to only use 2nd stage heat when it is really necessary.
 
I agree wholeheartedly with the lack of transparency at HAI. Tech support has repeatedly provided misleading and incorrect information, and they frequently imply I don't understand how the thermostat is supposed to work, when the person I am dealing with clearly does not even understand what the documentation says about how the thermostat is supposed to work. I am going to try one more round with them and see if I can get a clear answer.
 
My concern is that the EEC Heat part of the algorithm just does not work reliably. The whole selling point of these thermostats is mute if when it is near freezing or colder outside and  1) the house temperature can not be maintained (indoor temperature actually drops!), and 2) the first stage heat runs continuously, negating the hoped for energy savings.

 

[fcwilt]

Since this thing is supposed to learn has HAI given you any information how long the system has to run for it to learn something? How long have you let it run to see if aux heat ever turns on?
 
You stated the ECC value is for setting the rate of change but the documentation simply states the ECC criteria is 5 degrees per hour. Has HAI confirmed what this setting does?
 
It's not clear from the documentation if the aux-heat-diff setting is used/not used when ECC is on. It appears from your testing that it is NOT used but instead uses a fixed value of 3. Has HAI confirmed that it should be used?