Aircon not working as well as it used to

lockmc on 09/02/2021 - 22:23

Hi all.
Any air-conditioning specialists here?

We bought a 4 bedroom, single story house 2 years ago which has a ducted Brivis gas heater with add on cooling.
During the summer of 2018, we used to be impressed with how well the air con would work. The house would be an ice block really quickly when turned on and that would be with both zones on.
In mid 2019, we did a significant renovation which involved moving the kitchen and many other rooms.

Since then, the aircon hasn't worked very well. It takes the edge off but the temperature just doesn't seem to drop. House usually sits around 24 or 25 during summer but hot days it gets higher.

Changes during the reno:
- return air was relocated from floor level to in the ceiling (about 5 meters from original place but still central to the house).
- 1 duct on each zone has been wrapped and taped up as they aren't necessary due to floor plan change.
- We now have double glazed windows throughout

We've had 2 aircon companies in. First guys couldn't find an issue and never returned.
Second guys found the duct motors weren't wired properly (I put 2 new ones in and the air now comes out of the correct zones) and said it had no gas issues.

However, it is still no better. I think it's roughly a 18Kw system. The heater works great.

Im wondering if anyone has any ideas? When a single zone is on, the air seems cool enough but just doesn't seem to be pumping out at the rate that I'd expect. I can't see any leaks when in the roof. Condensor comes on and air is blowing.. I just feel it's a bit weak.

It was disconnected for a good 6 months so I am wondering if there is some programming on the thermostat (NC-1) that might have been wiped? Maybe some fans aren't turning on or something?

Anyone have any experience of suggestions? Callout fees add up and wondering if there's anyone on here that might have any idea what it might be as I feel alot of aircon guys are hit and miss.

Thanks

Home & Garden

Comments

  • MS Paint on 10/02/2021 - 00:25

    Enough r134a in the system? Leaking?

    Filters clean in return air?

    • lockmc on 10/02/2021 - 06:18

      We took the filter out because it was whistling too much.
      The last aircon guy said it ahd enough refrigerant.

      • MS Paint on 10/02/2021 - 06:49

        No filter? Any pets in the house?

        • lockmc on 10/02/2021 - 07:05

          Yep we have a dog. The first aircon guy removed it. Said it was not needed and was just restricting airflow (which is why it was whistling).

          • jason101 on 10/02/2021 - 07:49
            +2

            @lockmc: You have a ducted RC air con system with no dust filter installed on the return air - you have just found your problem. Al the dust which the filter would normally trap is now a moist clump on the heat exchanger in the ceiling, this will stop air flow over the coils and hence the air wont be cooled. You'll have to pull off the cover in the ceiling and clean it. https://www.ebay.com.au/itm/MIZU-FOAM-CLEANS-AIR-COILS-AIR-C…

            • lockmc on 10/02/2021 - 08:02

              @jason101: Thanks for the response.
              I feel like that might be a problem, but not the root problem.
              I say that because we had the issue whilst the filter was in. It was removed by the aircon guy who said it wasn't necessary and that he doesn't have one at his house (these guys rocked up without tools to test for leaks and went MIA and never invoiced so I guess I'll take what they say with a grain of salt).

              Also, heater works perfectly fine.. Its the aircon with the issue.

              Regardless, would any build up be in the heater unit as it all feeds through that? I can pop my head in and look. I'm assuming there will be some covers with screws where the return air enters the unit?

  • AustriaBargain on 10/02/2021 - 01:14

    Is it using the same amount of energy as it did before?

    • lockmc on 10/02/2021 - 06:18

      No idea. I assume so

  • Mechz on 10/02/2021 - 09:14

    So you halved the amount of ducting going to each zone?

    • lockmc on 10/02/2021 - 10:02

      No, each zone has 1 less duct.
      Zone 1 still has 5 ducts and zone 2 has 5.

  • lockmc on 15/02/2021 - 11:27
    +1

    Looks like we found the issue guys:

    https://imgur.com/a/KJ8tFmg

    I guess this is why you get aircon guys to install things :)

    • Peck on 16/02/2021 - 10:09

      Is that box just a junction box or does it do other things?

      • lockmc on 16/02/2021 - 11:23

        Its the output from the heater/fan unit before it gets split off into 2 zones and then into individual rooms.

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