Bryant Evolution Error - can anyone help me diagnose

[snmitch]

Hi to all the HVAC pros on this site.

I am a homeowner.

I just had a local installer rip my 10 year old 5 ton Goodman builder grade system and replace with 2 separate Bryant Evolution controled variable speed furnaces, and 2 2 stage communicating outdoor units; 4 ton upstairs, 3 ton down (in a 4000 sqft 2 floor house). I specified the furnaces to be 95% and the AC was contracted to be better than 16 SEER, 13 EER as this is what triggers various rebates.

In the process we added a lot of return air intakes all over the house (the old design had only one for the whole house).

Each system is zoned to provide 2 zones.

The evolution damper check complains about the zone 2 on my 3 ton downstairs unit. THe complaint comes after the damper check, but allows us to proceed and seems to work (airflow is huge to zone 2). The error I get is simply "check damper, zone 2". We did this and found it to be reversed in the airflow. We corrected this and it still complains with the same error and the numbers are unchanged.

Stats that the evolution reports on 'boot up' or if I run a damper check

static pressure measured (by the evolution) at .83 inch a 1200 CFM
Zone 1 (most of the downstairs) = 64%
Zone 2 (my office) = 18%
Damper leakage = 18%

My office is 1500 cubic feet of air.

Can anyone with Evolution experience tell me what the system is concerend about with the "Check Damper" error message?

Thank you so much.

Mitch

[beshvac]

The class i just went to said to make sure when only 1 zone is calling, that zone has to meet the minimum airflow of the unit in low speed or it will shut down. An office seems to not need much airflow.

[beenthere]

So the old system never cooled the house.
Since you increased size 2 tons?

[mwjhvac]

Sounds like a job for manual D better check it,

[snmitch]

So the old system never cooled the house.
Since you increased size 2 tons?

The only way to cool the house would be set it to cool 69 and let it run all day. Even then the guest bed and my office would be cooking at 80 other rooms would be make it to 75 to 78 ish. I would be bankrupt due to electric cost. In summer, with the tstat at 82 where we got used to settting it, my elect bill was of the order of $500 a month. Out side temps at my location routinely sit in the 95 - 105 daytime, 75 -80 nighttime from June to September.

I got about 6 bids for something new that would work and I could afford to run. Everyone had something different to say. One person was convinced my 5 ton sys was only drawing 3 tons of air through the return. Another was convinced my ducting was the the problem as well as returns. They all agreed the existing needed to go (of course) but there wasn't much consistency in the recommendations. A lot of people told me that R410a was a load of hype and I could do perfectly well with a brand new R22 based system (I begged to differ). I did a lot of reading. In the end, the guy I used was convinced the problem was return airflow and the fact that 5 tons simply enough for my house. I have 9ft ceilings so the volume of air is quite large. His price for 7 tons in two systems was the same as the 2 Trane bids for 5 tons zoned. So I went with that. (hope I didn't just break the rules - if so I appologize - newbie here).

My biggest compaint about the whole experience (my only complaint) was that there was no way to get brand independent empirical advice. I would have paid if someone who knew they weren't going to sell a system could have advised me.

Now it's in - I am in the one month a year where I neither heat or cool - so I can't tell if it is working yet. But early evidence from testing seems very good.

Mitch

[snmitch]

Sounds like a job for manual D better check it,

Yeh .... checking the damper, We have, kinda stumped with it. It seems to work - we can open, close it, it's in the right way (now). It's not blocked.

If only there was one manual to read and it provided useful diagnostic help I would try that.

I am a diagnostic engineer for a software company - not worried about reading a manual.

My installer is scratching his head a bit on this one, but he is going to talk to Bryant about it.

[dash]

What size is each damper??

Any modifications to the supply ducts?

Can you post pics of te indoor unit and connecting ducts?

[snmitch]

What size is each damper??

Any modifications to the supply ducts?

Can you post pics of te indoor unit and connecting ducts?

I'll post pics as soon as I can get back up in the roof.

Zone 1 is a 14" damper and goes from a supply plenum off the coil, via the damper, to a distribution box that has most of the supply ducts to the house attached. This was new work.

Zone 2 (problem zone) is an 8" damper, this comes from the supply plenum off the coil to a run of 8" flex, that runs to my office via a 8/6/6 Y connector. This is all that is that zone. I have aiflow set to LOW in the system setup. I just looked in the system events menu and it has 2 events about insufficient airflow to this zone. So I guess I am getting my installer back in.

Thanks for taking an interest everyone. Nice to have some one to brainstorm with.

[beenthere]

8" is a small zone. Even when its only in first stage.

[dash]

Setting the air flow to low limits the alredy small zone even more.Try max.,it may solve the issue.

If the supplies are noisey,they can increase the duct,grille,and maybe even the damper sizes.

Does the office have a return?

[snmitch]

Setting the air flow to low limits the alredy small zone even more.Try max.,it may solve the issue.

If the supplies are noisey,they can increase the duct,grille,and maybe even the damper sizes.

Does the office have a return?

Yes we added a 10" return in the office. Of course we added a lot of return air as the house had just one 20 x 36 return air upstairs fed to the air handler by a 20" flex line. We added return air in my office, in the living space downstairs and in the hall downstairs (for the 3 ton system). Upstairs we did similar for the 4 ton system; added return air all over the upstairs.

I set the airflow to LOW in the system menu thinking that this would tell the system to send as little air as possible to the zone. The manual says you adjust this setting if the airflow noise is too great or if there is too much air supply to the zone. I'll set it back to the default and see what it says. However - the "Check Damper" error message on Duct Assesment screen comes regardless of this setting (I have tried it at different settings).

Thanks for your ideas. This is great.

[dash]

Could be mis-wired and not openng and closig properly ,or at all.Does it maintain the temp.,and respond when there's a call to heat/cool?

Max air flow is worth a try,given what you have stated. You have only two zones,one is kida small,I'd try max.,not default,to allow more air tothe small zone,so the system doesn't have as much excess air to try and deal with.

[RoBoTeq]

Was a load calculation done on the house? Was the ducting completely redone? Sounds like you are saying that there was a ducting issue with the original 5 ton single system, so may we assume that the ducting has had a major overhaul with the increase in capacity along with adding zoning?

By the way, a properly sized system does run more and uses less energy to heat and cool our homes. Oversized systems that short cycle or staged systems that only run in the lower stages are real energy killers.

[snmitch]

Could be mis-wired and not openng and closig properly ,or at all.Does it maintain the temp.,and respond when there's a call to heat/cool?

Max air flow is worth a try,given what you have stated. You have only two zones,one is kida small,I'd try max.,not default,to allow more air tothe small zone,so the system doesn't have as much excess air to try and deal with.

Oh it responds fine and heats or cools the zone in question. Actually over heats or cools. I think you have nailed it - this zone is too small for the system. There are new errors in the log today citing execess static pressure. So - time for my installer to re-think his duct work.

Thanks for all your ideas.

[snmitch]

Was a load calculation done on the house? Was the ducting completely redone? Sounds like you are saying that there was a ducting issue with the original 5 ton single system, so may we assume that the ducting has had a major overhaul with the increase in capacity along with adding zoning?

By the way, a properly sized system does run more and uses less energy to heat and cool our homes. Oversized systems that short cycle or staged systems that only run in the lower stages are real energy killers.

Load calculation - I didn't see evidence of a 'calculation' from anyone who bid. I got lots of explanations of what is wrong, but they all seemed to me to be experience based, rather than a calculation.

Duct work was .. overhauled .. is the best word I can think of. For the down stairs we only did a limited cut in, so we found the ducts for my office and reworked them. Up in the attic the old system was 2 zoned; upstairs, downstairs. There was a duct board distribution box that we cut out and reworked with a sheet metal one and all the downstairs ducts were right there. My installer was dilligent on re-routing, shortening ducts and making the whole airflow equation make sense (to him). I think he may however have been unprepared for the evolution system and the minimum airflow needed for a single zone.

Thanks for your insightful questions/

Mitch