You need to increase your ductwork to fit the larger system you installed.
Your original ductwork was probably ok for a 2 ton system.
Now you're 50% bigger

 

X2. Either increase your ductwork to handle the i crease airflow or have them install a 2 ton system to match your ductwork.

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The WiFi has nothing to do with communication between the thermostat(Carrier calls it a UI) and the equipment.

If there are comm issues, then the wiring needs to be addressed. There are specific in the install manual and another method most knowledgeable techs know about.

Also, as stated you were NOT done any favors by upsizing the equipment!!!!
A duct assessment should have been done BEFORE and size change as well as a load calculation.

This unit, I believe, can be limited as to the stage it will go up to. This could assist in making it operate like the older smaller system, but you paid for something you now cannot fully utilize.
The original ductwork may not have been sufficient for the older system, either. The new system wants to deliver the proper amount of air, via the indoor blower, and will increase blower speed to do so. However if it runs into a restriction that increases the RPM/static too high you get the message you are seeing. If this is not addressed, the motor will fail, possibly multiple times, over its life and once out of warranty it is expensive!!!

 

Very much appreciate the feedback. All points well taken. Will be meeting with contractor to discuss issues next week. As stated, never purchased an HVAC system. However, did my homework and research. Got 3 contractors to provide estimates, all reputable in the area. I got three different capacities recommended, 2 ton variable, 2.5 ton single stage and this 3 ton variable. I had hoped I would get three similar opinions on capacity but that was not the case. Unfortunately, needed to make a decision in short order and made it. Don't know if trying a 2 ton would possibly be on the table. Also don't know what the trade-offs would be, if any.

Regardless, no one did a duct assessment and I understand the necessity - now. Regarding a duct assessment and load calculation. What is entailed - how do they assess the ducts? How do they do a load assessment? I read the ducts can be tested at various points along the duct work for airflow/pressure. How is that done? Last thing I want is for some guy to go up in the attic and simply look at the ducts and say they are too small for the system and need to be replaced.

Will also mention that the windows in the house are fairly new and the temperature remains steady on mild days when the system doesn't need to run. May mean there isn't a lot of leakage in the house itself.

Regarding the thermostat, it is has been off the internet since installation (going on 4 weeks) and is communicating/operating without fail. It has done everything it's been asked to do. Twice it was connected to the internet successfully and shortly thereafter stopped communicating. Those are the facts. Contractor has contacted Carrier. I did 20 years of programming as part of my career and learned that compatibility between software and hardware can always be an issue. Perhaps someone else has experienced something similar with the Infinity thermostat which is why I posted it.

I'll add that it is the second thermostat, as an effort was made to see if the first was faulty. Same result. The first time, the contractor checked the heat pump, fan coil and wiring. Also, I believe the contractor when he says they have numerous other installations of same system without this issue.

Thanks.

 

WiFi is not a big thing for my customers and therefore I have little experience with it.

For me it has been 50/50 for success with it out of about 10 systems that went Wifi.

I am quite positive it is on Carrier's end(or at least their product and software).

I have heard something about the connectivity aspect when the signal is lost, but I'm not sure I understand it.
Something about a dedicated/static address.

 

To pacnw:

Thanks for there response and agree. System is not dependent on it and did not buy the system for that feature. Also, not overly concerned about future firmware updates which it would facilitate. Will contact Carrier on the issue myself just to go on record. I also am not a network person and don't want to become one.

Going to focus on high static pressure because I realize it needs to come down. Regarding that, just a question, is it ever heard of to have a contractor at this early stage swap a 2 ton for a 3 ton, assuming they (and perhaps Carrier) can agree capacity will fix the issue?

I realize some of the implications for the contractor, but depending on what can help from the duct side, it should be asked. I've looked at the duct work in the attic and adding another central return should be quite doable as the distance from where it can be added to the fan coil might just be 40 feet on a fairly straight run. Again, the question from my lack of expertise is how to assess what will be needed and who to get to do it right.

 

If cutting a return in next to the unit didn’t help then adding a return 40’ away on help.

Funny a factory authorized dealer can’t check system static….


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You need the load calculations and duct assessment before anything else is done.

Is this a Carrier Factory Authorized Dealer? If so, they should be able to change that unit one time, at no cost, as part of that marketing program. Before they do the above calculations are necessary to make sure it is the correct move.

 

It is relevant to the size of the outdoor unit, but the issue is the ability to move the correct amount of air through your ductwork.

If ductwork will only handle X amount of air, then size the equipment to that and NOT to X plus.
Type of ductwork, flex vs metal/ductboard makes a difference in ability.
Design of the duct system plays a part, too.

Basically, 350-400 CFM/ton is the necessary air flow. 2 ton system needs 700-800 CFM and a 3 ton needs 1050-1200 CFM. This is a general rule and dependent on climate.

 

Sorry for delayed response to all. Had made a couple of replies to your posts a week ago but for some reason they did not appear. Talked to forum tech support and no explanation so I am now updating with new information.

I agreed with recommendation for a load calculation and duct assessment if needed. To restate, installed 3 ton infinity 5 stage heat pump (18VS), fan coil and thermostat. It replaced a 2.5 ton single stage and since infinity only comes in 2 or 3 ton, contractor chose 3 ton. That said, system is running steadily on stages 1 or 2 as hoped (no apparent short cycling) and keeping humidity at 48% or below.

The two post installation issues were thermostat not connecting to internet and working correctly and high static pressure in system. Since my last posts, contractor sent out a more experienced tech and thermostat now connected to internet as designed. So that problem is shelved.

The more pressing issue, high static pressure, was originally identified by the system itself. When you go into the Service icon (service and installation) and select "installation", you can run an "airflow verification test". This technician explained this was intended as a test of the duct system and it was tested at a full system 1050 CFM. The result was .83 static pressure with blower rpm of 1339. Also, a message appeared after blower rpm saying "too high please consider duct or filter change". Of course, no one is saying this is good

The tech then went to another test which was "check out", then "heat pump", then "cooling". You set the "heat pump check runtime" by selecting number of minutes and the specific stage (1 to 5) to test.

Could anyone weigh in as to the meaning (and importance) of the test results. The static pressures for this test by stage and corresponding indoor airflow CFM (no blower rpm measurements) were:

Stage 1 .07 static, 300 indoor airflow CFM
Stage 2 .16 static, 454 indoor airflow CFM
Stage 3 .32 static, not sure CFM
Stage 4 .55 static, 786 indoor airflow CFM
Stage 5 .67 static, 876 indoor airflow CFM

There were other stats as well. Temp outside was 91. Don't know if this is more relevant than duct test. Also, there were no "system events" recorded in past couple of weeks (since contractor last tested system).

Thanks again.

 

Absolute minimum airflow Carrier would require in stage 5 would 1050 CFM.......or 350 CFM per ton.

You would have lots of airflow for a 2 ton system.

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Thanks for response. Not entirely sure what you are saying. Is it that the duct test is designed to push 1050 CFM (what Carrier expects), under which static pressure should be .5 or below? Anything above .5 indicates restriction? And that is the idea of the test?

Then, in the heat pump test, for stages 1, 2 and 3, is it saying static is within limits under actual operation but not so for stages 4 and 5?

Just trying to better understand what is actually happening in my circumstance vs. what Carrier says it wants to happen. Is the heat pump test telling me the blower fan will be unstressed in lower stages but not so when in stage 4 and 5?

Thanks