Zoning a ducted Panasonic heat pump - pipe arrangement

Forums › Home Workshop DIY › Zoning a ducted Panasonic heat pump - pipe arrangement - splitters vs plenum

timmmay

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#281076 28-Jan-2021 13:11

I'm having HRV install a ducted heat pump fairly soon. Their current design is two ducts come off the plenum, one splits into two pipes to go to ducts for the lounge, one splits into three so there's one duct in each bedroom. There are mechanical dampers off the plenum and off the splitter to balance the air flow.

I might have a zoning system installed later, maybe Airtouch, maybe something else. An electrician I had over for an unrelated piece of work who does similar installs suggested if I was going to put a zoning system in that it might be easier if all the pipes came directly off the plenum. He said if possible use a Panasonic zoning system as then it can control fans and everything, but I don't know if they make one.

Any suggestions from people who have knowledge or experience in this area whether splitters are ok or if we should have all pipes off the plenum? I have also asked HRV but I'd like another opinion as well.

D1023319

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#2643926 29-Jan-2021 08:47

In our underfloor ducted heatpump - all 5 outlet pipes come off the plenum (with one spare).

I was told its all about balancing the inlet and outlet air volume so the two inlet pipes are twice the size of the outlet pipes and located close to the plenum
As the length of the pipes creates different friction on their air moving through them - to achieve a consistent volume of air in each room - there are permanent restrictors on each outlet pipe to balance the airflow (as distinct to the zone controls where you can set different tempts for each room)

So personally I'd leave this decision to your installer noting once installed they will use a airflow meter to balance the pipes.

timmmay

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#2643928 29-Jan-2021 08:51

Thanks :)

HRV have said there's no option anyway, the plenum has two outputs and they can't change it. I suspect they buy a readymade kit from Panasonic and install it, which is why they're at least a few grand cheaper than anyone else. I guess if I want to change anything later I can always change that part, it doesn't look that expensive. Only reason I might change it is for automation, which would be done by a company who know what they're doing.

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#2644041 29-Jan-2021 11:41

I'd ask you installer now whats the impact in future if you restrict airflow to the outlets to have different temperatures in each room.
It may cause your system issues such as make the widest open outlet noisy or overload the fan.
I suspect unless you do it right from the get -go you will be locked in without a expensive upgrade.

timmmay

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#2644047 29-Jan-2021 11:55

Thanks D. I've already told them up front that I want different temperatures in each room. They said there are dampers on the plenum and on each output of the splitter that allow airflow to be balanced between the rooms, and they regularly do that kind of thing. I've said a quiet system is a priority, so they're doing things like putting two ducts in the lounge instead of one to reduce noise and putting in a decent sized return grill - from memory something like 80 x 40cm.

The main reason I'm interested in these details are in case I want to put more automation on it in future. The sparky that visited yesterday pointed out it might be good to be able to shut off the lounge heating overnight and just heat the bedrooms to keep costs down, particularly I guess since the bedrooms will have less airflow and the lounge will have more airflow to keep the temperatures down in the bedrooms. Though I'm not all that bothered by power bills, the house is fairly well insulated and bills tend to be reasonable.

geoffwnz

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#2644873 31-Jan-2021 21:02

Is it too late to look at a different brand that does actually do zones? Currently getting a quote for a Daiken ducted system which can have up to 8 zones.

Or are you fairly committed to the HRV solution now?

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timmmay

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#2644879 31-Jan-2021 21:11

Well, HRV arrive on Tuesday to install it, so technically I could cancel but it would not be popular. I don't know if I'll need to bother as I think the standard system would be ok. I can always have whoever does airtouch install a new plenum if it was critical.

At $9K for HRV / Panasonic it was cheaper than the Fujitsu ducted system for $13K that also wasn't zoned, and I could get $9K past my wife but not much more. How much is it costing you for a zoned ducted system @geoffwnz ?

geoffwnz

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#2644887 31-Jan-2021 21:21

timmmay:

Well, HRV arrive on Tuesday to install it, so technically I could cancel but it would not be popular. I don't know if I'll need to bother as I think the standard system would be ok. I can always have whoever does airtouch install a new plenum if it was critical.

At $9K for HRV / Panasonic it was cheaper than the Fujitsu ducted system for $13K that also wasn't zoned, and I could get $9K past my wife but not much more. How much is it costing you for a zoned ducted system @geoffwnz ?

Coming in at around $11.5k for 6 outlets all individually zoned. So pretty much in the middle or your two quotes.

But yeah, if you can make yours work how you need it to, that's the main thing really. :-)

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timmmay

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#2644907 31-Jan-2021 21:58

geoffwnz:

Coming in at around $11.5k for 6 outlets all individually zoned. So pretty much in the middle or your two quotes.

But yeah, if you can make yours work how you need it to, that's the main thing really. :-)

That's a pretty good price for a zoned ducted system. Where'd you get that?

I'd say I'm committed - contact signed, they got the unit in, install is booked, wife has ok'd it, I'm sure the HRV will be fine and a good advance on the current high wall. Maybe in 10 years when it's due replacement if I'm still here I'll go that way, or I'll install the aftermarket kit if I really need it.

geoffwnz

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#2644975 1-Feb-2021 07:22

timmmay:

geoffwnz:

Coming in at around $11.5k for 6 outlets all individually zoned. So pretty much in the middle or your two quotes.

But yeah, if you can make yours work how you need it to, that's the main thing really. :-)

That's a pretty good price for a zoned ducted system. Where'd you get that?

I'd say I'm committed - contact signed, they got the unit in, install is booked, wife has ok'd it, I'm sure the HRV will be fine and a good advance on the current high wall. Maybe in 10 years when it's due replacement if I'm still here I'll go that way, or I'll install the aftermarket kit if I really need it.

Requested a quote from the Daiken saite itself, got contacted by a local installer, Blizzard, on their behalf who came round to do the quote last week.

Put down a concrete pad for them over the weekend for the external unit as opposed to the "sitting on pavers" they had proposed. Doesn't save me anything but wasn't a fan of having a fixed plumbed unit on pavers that can settle over time.

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timmmay

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#2644980 1-Feb-2021 07:51

Blizzard have a good reputation. $11.5K for a zoned ducted heat pump is great, wish I'd done that, but a bit late now I think.

geoffwnz

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#2644984 1-Feb-2021 08:09

timmmay:

Blizzard have a good reputation. $11.5K for a zoned ducted heat pump is great, wish I'd done that, but a bit late now I think.

It's never too late, it'll just be some annoyance. But yeah, I can understand not wanting to mess them around when you are this close to install time.

Yep, did a quick google for Blizzard before I responded to them. Couldn't see anything negative about them. And they were very prompt at responding to my questions.

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timmmay

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#2644990 1-Feb-2021 08:38

If I'd discovered this a couple of weeks ago then I'd have probably tried to switch, but I have a contract and they're booked for tomorrow so I think it'd be pretty unreasonable to cancel now, and there's no cancellation clause anyway. I reckon I'll be ok without zoning and if I need it later I'll retrofit.

geoffwnz

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#2644992 1-Feb-2021 08:45

timmmay:

If I'd discovered this a couple of weeks ago then I'd have probably tried to switch, but I have a contract and they're booked for tomorrow so I think it'd be pretty unreasonable to cancel now, and there's no cancellation clause anyway. I reckon I'll be ok without zoning and if I need it later I'll retrofit.

Yep, that's fair enough too. I could probably do my place without zones also, being as it's really two distinct areas, but the option is there, might as well make use of it.

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#2644996 1-Feb-2021 09:05

timmmay:

If I'd discovered this a couple of weeks ago then I'd have probably tried to switch, but I have a contract and they're booked for tomorrow so I think it'd be pretty unreasonable to cancel now, and there's no cancellation clause anyway. I reckon I'll be ok without zoning and if I need it later I'll retrofit.

That is what we did. I have tried to ‘tune’ the system by winding the diffusers in each room in or out to adjust the flow. Still not perfect and very dependant on whether doors are open or closed.

I investigated an Airtouch4 system last year because I wanted to gain wireless/remote control of our wired Fujitsu system. Initially I was not going to zone but some rooms in the house still go slightly too hot or cold, so it may need to be considered.

My biggest concern with retrofitting zoning is tuning. The duct design with plenum and branching was done without zoning in mind. So whether the network of ducts would handle the back pressure of valves not being at the plenum would need to be assessed.

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timmmay

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#2645126 1-Feb-2021 10:30

Dingbatt:

That is what we did. I have tried to ‘tune’ the system by winding the diffusers in each room in or out to adjust the flow. Still not perfect and very dependant on whether doors are open or closed.

I investigated an Airtouch4 system last year because I wanted to gain wireless/remote control of our wired Fujitsu system. Initially I was not going to zone but some rooms in the house still go slightly too hot or cold, so it may need to be considered.

My biggest concern with retrofitting zoning is tuning. The duct design with plenum and branching was done without zoning in mind. So whether the network of ducts would handle the back pressure of valves not being at the plenum would need to be assessed.

Yeah, agree. Though my very limited understanding is a plenum isn't particularly expensive and changing the ducting shouldn't be a huge job. I'll hopefully not have to bother, but if I do, oh well.

With the system I'm getting you don't tune with the diffusers, there are things on each pipe up in the ceiling (I forget the name) to control the airflow. Bit more of a hassle to do that of course, but with the diffusers I've gotten they have holes in the face so winding them in and out won't do much.