ReplyWIth a timer, when call for heat ends, the inducer and fire should stop right away and the blower runs for 90 seconds or whatever that off delay is set for. The blower should never stop immediately.
New Guest
I have been having difficulty finding someone that can give me the proper information on this, hoping to find someone here that can help.
I have a Trane XL80 furnace (U060R936K) and as I was verifying the operation of the heating stages (did not have 2 stage tstat) when I noticed that once the tstat kicked the 2nd stage off the blower turned down to low speed for 1st stage heating right away.
According to the installation manual and process of the logic, once the 2nd stage is satisfied the tstat will open the relay at that time the draft blower slows and 2nd stage gas shuts off. The blower then should run at high speed for approximately 30 seconds. My concern is the blower shuts off as soon as the command goes away for the 2nd stage. I am not sure if this is normal, maybe because the 2nd stage only ran 5 minutes and was not hot enough to constitute a longer run time.
I am going to be doing some flow checks today with a hood so I need to let the system run longer. I will see if it does the same thing or will run longer since it will be hotter. Any feedback would be greatly appreciated.
Global Moderator
WIth a timer, when call for heat ends, the inducer and fire should stop right away and the blower runs for 90 seconds or whatever that off delay is set for. The blower should never stop immediately.
New Guest
The run timer works just fine for the first stage, no issue there. I believe it is factory set at 100 sec and the dip switches remain there.
This is only whem stage two heat is commanded. It ignites, blower speeds up, when tstat turns off stage two but keeps stage one on, the med-low blower speed switches to just low speed (the indoor blower/return). So before the heat completely shuts off I am good, it is only when stage two drops.
Sorry if I am making this more confusing than it needs to be.
Global Moderator
The timer is a fixed 10 minutes of low before timing up to high (whether you need more heat or not. Usually not)
But something wrong with the board that is stopping the blower immediately. Hard on the limit and heat exchanger. Get a dealer to check it out ASAP.
New Guest
2nd stage is controlled by the thermostat and not the unit itself, so it should not be running that timer.
Even running longer today high speed reduced to low speed as soon as it went from 1st and 2nd stage to just 1st stage.
Just to be clear:
1) 1st stage on with low blower speed
2) Command from tstat to turn on 2nd stage (with this tstat, way too soon and unnecessary)
3) 1st and 2nd stage on with med-low blower speed
4) Tstat decides it does not need 2nd stage heat
5) 2nd stage gas turns off and blower immediately goes to low speed
6) 1st stage on with low blower speed until temperature is met
I am disabling 2nd stage. Not really liking how it is heating the house anyway or how this new thermostat is controlling it. Honeywell can't seem to give me answers and all local Trane service techs can't tell me if this is normal operation or not (my original question).
Ran 5 years without 2nd stage and I was happy with how the house heated. I was hoping this could just help in big temp jumps but it seems to command 2nd stage on soon after 1st stage even just for 1 deg change. Thanks for your replies.
Global Moderator
Thought you were saying the blower stops when call for 2nd stage ends.
Sounds like all is working as it should. If you don't want high so fast, there are stats where you can tell them how quick to bring on 2nd stage.
New Guest
OK, thanks. Yes I was afraid I messed up the explanation.
I will do some research for a better thermostat that gives me the control I need. I just purchased this one because I wanted wifi access when I am in and out and the old one was drifting a little.
Professional Member*
I think on this board, we're seeing a lot of these wifi stats. I wish the companies put 10th of the effort into the logic/loop control that they put into the communications and screen graphics. There's have not been very good reviews on here on the Ecobee or Nest. Some of them it seems have been a massize PITA to install. Sounds like you have a Honeywell. Usally they have soem of hte best temperature controls out there. But maybe in order ot afford the othe facy features, they put the "guts" of a $20 thermostat inside.
Keep in mind that thermostat location can play a major role along with equipment sizing. If you can operate the furnace on low stage only for years, then it's probably oversized and defeats the point of being 2 stage in the first place. 1st stage is slightly less efficient that high stage too.
Professional Member*
Sounds to me like the stat needs to be adjusted as to how long it will run before 2nd stage kicks in. Other wise it sounds like the unit is operating as designed. When 2nd stage call goes away it should drop to 1st stage till the stat satisfies. Dropping ot low speed fan should not hurt anything.
New Guest
Thanks for the all feedback.
My only concern was the difference in operation vs. what the manual states. The do not go in any detail like there is a variable run timer from high to low speed and it is up to 30 sec, but I assume system run time in 2nd stage must play into this.
Here is what the manual says, probably should have posted this before:
2nd stage satisfied, 1st stage still called:
R and W2 thermostat contacts open signaling that 2nd stage
heating requirements are satisfied. The induced draft blower
is reduced to low speed allowing the 2nd stage pressure
switch contacts to open and the gas valve is reduced to 1st
stage. After approx. 30 seconds the indoor blower motor is
reduced to low speed.
Yes, I have a Honeywell RTH6580WF. It was very easy to setup and my only concern with it is the 2 stage control basically sucks (hence just disabling it).
I didn't think there was a big difference in the efficiency stage to stage, or at least end cost of operation. Looking at the spec sheet 1st stage input vs capacity is 80% and 2nd stage is around 78%. Kind of splitting hairs but I was always under the assumption that you are better off with 1st stage running (but I have been wrong before). You might be right on the sizing, I always thought it was undersized until I realized it was only operating on one stage.
I did some balancing of the system last night with what appears to be good results. I have a nice distribution throughout the house now and 1st stage seems to help the comfort level out vs. the few days I had with 2 stages.
New Guest
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Last edited by beenthere; 01-18-2013 at 10:37 PM. Reason: Non Pro * Member
God Speed, Jim. We'll miss you - 2-26-23
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