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klingon 02-11-2012 03:58 PM

Q for Lennox iComfort users or Lennox Pros
I have the SLP98/XP21/iComfort combo and seem to be having issues with the iComfort. I was wondering if anyone may be seeing the same or can share some of your settings or experience with your system.

I have propane so my goal is to run as much on HP as possible. Issue I have with the iComfort is that it seems to "freeze" when outdoor temp gets closer to the Low balance point setting.

My current settings are :
Setpoint - 67 constant no setback
High Bal Point - 25
Low Bal Point - 20
Stage timers - 20 mins
Temp staging - 1,1,0.5,0.5,0.5,0.5
all others at default

What I'm noticing is -

1. The stage timers are somehow tied to the High bal point. It wont go to the next stage even after 20 mins if outdoor temp is below the high bal point, so I set mine fairly low at 25 so the stage timers will work. According to the manual, the stage timers are not even supposed to work as the furnace controls it?? Not sure how this can be the case for the HP part. It seems to work for me under the right conditions! Not sure if this is a feature or a bug. Does your stage timer work for the HP?
2. As outdoor temp gets closer to the low bal point, the HP will continue to run on low and not go to high stage even after 20 mins. Seems to tie in with my point above. Or sometimes it will go high and then fall back to low and continue at this stage even when it cannot meet demand and the indoor temp drops below the setpoint. This is when the iComfort seem to "freeze" and wont even turn on the furnace even when outdoor temp drops below the low balance point. If I manually drop the setpoint so the unit will stop and then set it back to the original setpoint, then everything starts to work again as set and the furnace will come on.

My installer warned me against using the iComfort as they find it has a lot of bugs and I somehow gave Lennox the benefit that such a company will not release a buggy thermostat. Guess I may be wrong. Unfortunately I'm their only customer using the iComfort so they're not able to provide much help. I'm pushing for them to get me in touch with a lennox engineer. Hoping someone here can help in the meantime.


yuri 02-11-2012 04:39 PM

Have them contact Lennox tech support and CAREFULLY read the install manual. The thermostat wire has to be shielded and seperated in a special configuration from the high voltage etc. There is a bulletin about that and they added it to the install info and wiring info. Not a "buggy" tstat just needs the proper wiring.

klingon 02-11-2012 05:14 PM

Thanks Yuri. So you think its the wiring which is causing my problems? Can you post a copy of the bulletin so I can approach the installer? They used back the regular thermostat wiring as it started off with a Honeywell IAQ and I later requested for the iComfort.

And what about the stage timers? Is it supposed to work for the HP? According to the iComfort manual its not supposed to work but it seems to be working under the conditions I described. Very confusing! BTW, I have the 12/10 firmware version for the iComfort.

"The 2nd Stage Delay Timer (when Staged Delay Timers is Enabled)
is used for both HEATING and COOLING. However, if the system has a variable
capacity furnace, 2nd Stage Delay Timer will only be used for COOLING
(not for heating, as the variable capacity algorithm ignores delay timers)."

yuri 02-11-2012 05:23 PM

I don't do heat pumps where I am as it is too darn cold. If they used more than 4 wires between the furnace and outdoor unit the extra wires need to be joined together and connected to the C terminal as it grounds them and eliminates interference. I cannot link that bulletin as the site is locked but they should be able to easily get that info from tech support and any latest revisions to it or other pertinent info. The tstat wire should not be tightly attached to any high voltage wiring and that applies to all manufacturers not just Lennox.

yuri 02-11-2012 05:31 PM

We also have a tech here Marty who does a lot of Lennox heat pumps and may know your system better so hang in here for a day or so.

It is also VERY important that the furnace and outdoor unit be grounded VERY well. Especially the furnace as the board is ground sensitive. Make sure it has 0 Ohms resistance to a copper water line and use a cheater wire to test if necessary. A loose or floating ground could be the problem too. I had one where the house was grounded to a copper water line and the ground clamp on the pipe was loose and giving a bad ground.

klingon 02-11-2012 05:51 PM

Yuri - Thanks for the prompt response. I know the ground is good as I just replaced the ground copper wire from my breaker box to the ground rod outside. I'll still test the 0 ohm after this just to be sure. If you or Marty can cut and paste the bulletin, that will be very helpful to re-enforce my case with the installers. Does the bulletin state the reason for this requirement? The iComfort manual unfortunately also stated that shielded wire is NOT required :eek: But the installer did tie the tstat cable together with the high voltage cable along with the copper lineset.

Marty - hope you can confirm the stage timer question or add some advice to my issue.


yuri 02-11-2012 06:20 PM

Lets try this and see if it works. It is a pdf file and I cannot copy and paste it. Let me know if it works OK 4 U. Hopefully they used clean decent #18 thermostat wire from the tstat to the furnace and outdoors. NO small telephone wire or ratty old wire!

klingon 02-11-2012 06:26 PM

it works...thank you for posting this. I'll bring it up with the installers on Mon.

yuri 02-11-2012 06:29 PM

reread my post as I added to it. Good Luck. If they are unco-operative then you can get in touch with the district manager etc. You have the most expensive units and they are VERY concerned that they work properly and will help you. The technology in there can be intimidating for a lot of techs.

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