Daikin ducted heat pump over shooting its targets

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tweake

2391 posts

Uber Geek

#3172332 16-Dec-2023 12:59

Obraik:

It mostly followed the plans, the only difference is that the ERVs return vent is in the hallway rather than the kitchen/dining area as it is on the above plan.

The evening and this morning were much improved after changing it to use the controllers sensor yesterday afternoon. I set it to 22 overnight this time and when we got up this morning the controller was showing the room was 21 - no hoody or socks required this time. I also changed the fan behaviour for cooling mode - it was set to run the fan at the set speed when it wasn't actively cooling so I've set it to the setting that puts it into low-low mode. The fan for heating mode was set to turn off when it wasn't actively heating, so I didn't need to adjust that.

good to see you got the temp problem sorted. however that and other things tells me this was never setup properly in the first place.

the big problem is that you need to have the hvac fan running all the time for the ERV to work properly. the hvac is what distributes the air. with the hvac off the ventilation air is going to come out of the hvac return vents, and probably blow a bit of dust off the filters back into the air. especially as the ERV return is in the same space. ie the ventilation air will go down the hvac return to the ERV return and not mix with the house air effectively doing nothing. so you need to set it so fan runs all the time. the other option is to put one ways or dampers on the returns so if the hvac is off they shut and ventilation air is forced through the hvac piping, but remember that it will take the easy route so it won't be well distributed. another crude way is to put the vent supply in the hallway, so ventilation air goes into the hallway and is picked up by the hvac returns. when hvac is not running it then distributes by the hallway, which is not great.

disappointing to see the ERV outlet and inlet so close to each other. should really be a lot further apart.

does the ERV have a separate air filter? common trick is for them to use the built in filter which is only there to protect the core not clean the air. plus that filter may be hard to find in years to come. far better to have a standard sized filter placed before it so it does the air cleaning. also looks like its a long way from the access hatch so you will have fun changing filters. might be a good idea to move the ERV intake down to the garage and have a separate filter mounted by the access hatch.

no mention on returns from each room.

how is the bathroom ventilation done? its pretty common to use the ERV as the bath room vents. otherwise you need to factor in make up air for the bath fans as well as the range hood. hows that been done?

the kitchen hvac vent should have been further away. by placing it so close to the rangehood it reduces the effectiveness of the range hood (assuming ceiling vent). the best is a floor vent so replacement air comes up from underneath.

Obraik

2123 posts

Uber Geek

#3172334 16-Dec-2023 13:19

To be quite honest, no, I haven't been very impressed with the HVAC company that was used. Initially they had put both units on separate controllers, with the heat pump being on the standard controller (BRC1E63) and the ERV on the stylish controller (BRC1H62W). However, as you're probably aware, the stylish controller can do both so I questioned why we needed two separate controllers. They went back to Daikin about it and realised that yeah, they could consolidate them both into the one - left a hole in the wall for the builder to fix up though 🙂. We were also never given a handover or care guide on the system, which I mean yeah, it's pretty obvious to me that you need to periodically clean the filters in the return vents accessible inside the house but there was no mention of the ERV's filters. We actually discovered the manual for the ERV in the ceiling while running some network cables that highlighted that yeah, once a year you're meant to pull out the heat exchanger modules and wash them, which will mean climbing through the ceiling to get to the unit. There are no filters for the ERV on the outside, other than a bit of mesh on the intake that has prevented some large bugs from getting sucked in.

Bathroom ventilation is done by traditional extractor fans rather than the ERV. All doors were undercut to allow air to flow out of them when they're closed.

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tweake

2391 posts

Uber Geek

#3172338 16-Dec-2023 13:35

Obraik:

To be quite honest, no, I haven't been very impressed with the HVAC company that was used. Initially they had put both units on separate controllers, with the heat pump being on the standard controller (BRC1E63) and the ERV on the stylish controller (BRC1H62W). However, as you're probably aware, the stylish controller can do both so I questioned why we needed two separate controllers. They went back to Daikin about it and realised that yeah, they could consolidate them both into the one - left a hole in the wall for the builder to fix up though 🙂. We were also never given a handover or care guide on the system, which I mean yeah, it's pretty obvious to me that you need to periodically clean the filters in the return vents accessible inside the house but there was no mention of the ERV's filters. We actually discovered the manual for the ERV in the ceiling while running some network cables that highlighted that yeah, once a year you're meant to pull out the heat exchanger modules and wash them, which will mean climbing through the ceiling to get to the unit. There are no filters for the ERV on the outside, other than a bit of mesh on the intake that has prevented some large bugs from getting sucked in.

Bathroom ventilation is done by traditional extractor fans rather than the ERV. All doors were undercut to allow air to flow out of them when they're closed.

just having a closer look at the mo.

to me, with out proper plans with measurements on them, it looks like they oversold the ERV. its seams oversized. the model down (the 250) would be perfectly fine. the 350 on low speed will still be to much.

if its setup right the controller should tell the hvac to run whenever the ventilation is on, which should be always.

need to look through the manual to see if the ERV has a boost mode, you should really have the bath fans and especially range hood set to run the boost mode to provide replacement air. (assuming its dual motored).

i would relocate the the ERV intake and install a separate filter above the garage to make it easy to change it. ERV filters, depending on that they use and location, usually need replacing every 6 months or so. normal ventilation filters every 12 months.

also looking at the hvac duct sizing has got me a bit puzzled. the bedroom supply and living room supply look swapped (but i cannot tell lengths in this) and a huge amount of return from the bedroom wardrobe. has the wardrobe got a door? plus the supply looks choked for half the house.

tweake

2391 posts

Uber Geek

#3172357 16-Dec-2023 15:05

i forgot one thing, as no mention of a dehumidifier you will need to keep a close eye on humidity levels. the downside to ERV's is they keep the moisture in (as well as out). your no longer using ventilation to remove household moisture. so i recommend some gauges mounted in easy to see places.

Kickinbac

427 posts

Ultimate Geek

#3172441 16-Dec-2023 17:14

Obraik:

It mostly followed the plans, the only difference is that the ERVs return vent is in the hallway rather than the kitchen/dining area as it is on the above plan.

The evening and this morning were much improved after changing it to use the controllers sensor yesterday afternoon. I set it to 22 overnight this time and when we got up this morning the controller was showing the room was 21 - no hoody or socks required this time. I also changed the fan behaviour for cooling mode - it was set to run the fan at the set speed when it wasn't actively cooling so I've set it to the setting that puts it into low-low mode. The fan for heating mode was set to turn off when it wasn't actively heating, so I didn't need to adjust that.

Sorry, off topic, but I wonder what programme they use to do that drawing?
And they have calculated the loads for the rooms so you can see the airflows each room needs.
This is actually quite good and more than a lot of installers will provide. I hope they balanced it!

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