HVAC-Talk: Heating, Air & Refrigeration Discussion banner
Cancel
Create thread New Forums

New Installation - Ductwork making popping Noise.

Jump to Latest
1 - 20 of 40 Posts
M

Manage Password

· Registered
Joined
·
56 Posts
Discussion starter · #1 ·
We got a new Trane gas furnace installed last fall. It is under warranty. With the hot weather we noticed there was a banging noise on start up and shut down when the AC kicks on or off. It never used to do that before with the old furnace. I contacted the contractor and explained and I suggested maybe the blower fan was set too high. The AC is a 1 1/2 ton Carrier unit. The HVAC contractor said he could have a look but if the speed is set within specs I would have to pay for the call and anything that needed to be done after that.
Here is what they replied with "If its found that the airflow is set correctly (600-700 CFM depending on the size of the AC) then the call would not be covered under the install warranty and we would need to follow up with myself to inspect the ductwork and provide a quote to repair those sections. If the airflow is set too high, we would cover the call however ducting should be able to handle the highest airflow setting on a properly sized furnace."
My question is: Is it fair for me to have to pay for this service call or not?
 
#5 · (Edited)
Ask for this report as mentioned, a startup/commissioning report, things like temperature rise across HX, static pressure checks ( as mentioned ) amprege reading of motors. Etc are within manufacturer guidelines.

Sounds like your A/C is existing and only the furnace was changed. What size was your old furnace in BTU, was it the same width as the new furnace, was your old furnace a 80% and you now have a condensing furnace. Did they add a transition sheetmetal piece between the coil and furnace whereas your old furnace the coil is attached to the furnace directly.

When they had the old furnace removed, did they clean in indoor coil inlet side, and made sure coil was thoroughly cleaned?


https://www.energystar.gov/sites/de...ent/National HVAC Commissioning Checklist ENERGY STAR Certified Homes_Rev10.pdf
 
Save
Like Like
Discussion starter · #6 ·
Do you think the installer would be ticked off if I requested a copy of the startup report, if one actually exists? Is it standard practice to provide a startup report and provide the customer with a copy? My AC never made any ductwork oilcanning noise prior to the new furnace being installed so I don’t get why the installer is trying to put the onus on me. At the very least I would expect he identifies the blower speed for free and then and only then determine if any work outside warranty needs to be done. The way he responded makes me wonder if he is just going to claim all is set to spec and then turn around and charge me for the call and anything else he can tag on. Not a good first impression…
 
Discussion starter · #7 ·
PS - I checked the papers that came with the install and I never received anything resembling a startup report… And the A/C is an existing unit that was there prior (15+ years) to the new furnace install.
 
#8 ·
Is the furnace located where you can have easy access to the duct work? Often times on furnaces in a basement the return drop is too small for the air moving through it and it will suck in when the blower starts and pop out when it shuts off. Have someone start the system and the thermostat then after a few minutes and you hear the noise have them shut it off. Keep an eye on the duct for the widest side to move.

I don't want to put your dealer in a bad light here but on XR equipment I cover for a year, XL is 2 years and this is in my dealers contract with the distributor. He may not have one but I have no problem signing the contract because I would do it anyway. Just one more reason we say it is not the name on the box but on the side of the truck.
 
Save
Like Like
#9 ·
Chances the blower fan speed for heat setting and cool setting are different, which is not unusual to do. Do you notice more air coming out of the supply registers than before and is it more noisy, or the return air more noisy than before?
 
Save
Like Like
#10 ·
Manage Password said:
PS - I checked the papers that came with the install and I never received anything resembling a startup report… And the A/C is an existing unit that was there prior (15+ years) to the new furnace install.
Click to expand...
If you look in the back of the manual there might be one there
 
Discussion starter · #11 ·
I do notice quite a bit more air coming out of the registers when the A/C goes on compared to prior the new furnace install. The contractor says it could be the old furnace had the same blower speed for both the A/C and the furnace and now the new one has a different and higher blower speed which may be why the ducts are popping when they didn’t before. Could this be likely or is it a way to justify charging for a service call and possibly more extras?
 
Discussion starter · #12 ·
I checked the booklet that came with the furnace and there is nothing that resembles the startup report that pecmsg spoke about and posted an example of or a link to a blank one. By the way, the furnace is a Bryant forced air gas model #926TB
 
#14 ·
What does the contract say, as you mentioned a Trane furnace? Now you say Bryant.

What’s on the contract you signed for a brand and model number of furnace. You should have a one year labor warranty on the furnace?

What did they do a switch a rue on you without telling you, if contract says Trane?
 
Save
Like Like
#15 ·
The contractor is right that there are different speeds for the blower between heat and cool with one important exception. Those speeds are not preset to the correct speed, they have to be set to the needs of the equipment. Often times anymore heating speed is greater than cooling. If they did not set the speed by checking static pressure of the system then both could quite possibly be the wrong speed.
 
Save
Like Like
#17 ·
Discussion starter · #19 ·
So this is a separate report filled out by an HVAC tech but not always performed or routinely performed with every installation. I do not see anything like that in the owner’s manual.
 
1 - 20 of 40 Posts
You have insufficient privileges to reply here.
About this Discussion
39 Replies
5 Participants
Last post:
kdean1
HVAC-Talk: Heating, Air & Refrigeration Discussion
posts
5M
members
275K
Since
2000
The #1 HVACR Community
Full Forum Listing
Explore Our Forums
AOP Residential HVAC/Refrigeration(Beenthere Zone) General Discussion Tech to Tech Chat - Residential Controls Refrigeration & Ice Making