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AirGreen × ACD · 3 zones
Three rooms on one MPD outdoor unit, the third with a large head
Sold and installed by AirGreen. Montréal, Laval, Longueuil, the South Shore and the North Shore.
ACD · MPD multi-zone · 3 heads
Four MPD outdoor units take three heads, from the MPD 24,000 to the MPD 42,000. Pick the size of each head: the tool reads ACD’s combination table and tells you which outdoor units ACD lists your trio for, and why a 24,000 head changes everything.
Updated November 5, 2026 · ACD MPD sheets and manual, AHRI certificates
ACD MPD-22 and English multi-zone sheets
Head trios published, outdoor unit by outdoor unit
Trios printed in both ACD sheets. The MPD 18,000 has only two ports.
This page answers
With three ACD heads, can my third room have a large head?
On this page
The ACD shop · 3 zones
Four outdoor units, from the MPD 24,000 to the MPD 42,000, each sold with three heads. Price on quotation.
01 · The 24,000 head
Pick the three sizes. Add a 24,000 head and watch the list shrink to the MPD 36,000 and 42,000.
My three rooms
Head 1 (BTU)
Head 2 (BTU)
Head 3 (BTU)
Combinations: ACD’s table, trios printed in both the MPD-22 sheet and the English multi-zone sheet; the order of the heads does not matter. The table reads by size: a 09 + 09 + 18 trio stands for two 9,000 heads and one 18,000 BTU/h head, whatever their type. Line set: MPD-22 sheet and MPD manual (INS527), p. 14. Heating: AHRI certificates of August 9, 2022, at 8.3 °C; for the MPD 42,000, the nominal value of the MPD-22 sheet, with no test temperature printed (the same sheet gives 42,500 BTU/h for the MPD 36,000).
The four outdoor units for this trio
| Outdoor unit | Trio published | Ports left | Line set | Heating at 8.3 °C |
|---|---|---|---|---|
| MPD 24,000MPD24KCH21S-OProduct page | yes | 0 | 60 m in total20 m max. per line | 26,000 BTU/hAHRI certificate 202110497 |
| MPD 30,000MPD30KCH21S-OProduct page | yes | 1 | 70 m in total25 m max. per line | 30,000 BTU/hAHRI certificate 202110500 |
| MPD 36,000MPD36KCH21S-OProduct page | yes | 2 | 75 m in total25 m max. per line | 36,000 BTU/hAHRI certificate 202110503 |
| MPD 42,000MPD42KCH21S-OProduct page | yes | 2 | 75 m in total25 m max. per line | 45,000 BTU/hnominal per the MPD-22 sheet, no certificate |
✓09 + 09 + 18: the MPD 24,000 is the smallest outdoor unit ACD lists this trio for, with 60 m of line set in total and 20 m max. per line.
02 · The fourth head
Same outdoor unit, same AHRI certificate 202110500: the fourth head shortens the list.
3 heads · AHRI certificate 202110500
4 heads · AHRI certificate 202110500
With three heads, the MPD 30,000 has 7 published trios and takes an 18,000 head. With four, the MPD-22 sheet gives it only 3 combinations, all with 9,000 and 12,000 heads; ACD’s English sheet adds 09 + 09 + 09 + 18, which the MPD-22 sheet does not print.
03 · Did you know
30 m
The MPD 24,000 pre-charge covers 30 m: three 10 m lines already reach it. Beyond that, up to the 60 m published, the installer adds 0.2 oz of refrigerant per foot.
ACD MPD-22 sheet, p. 2; MPD manual (INS527), p. 1524,000
The trios published for the MPD 24,000 and 30,000 stop at 18,000 heads. For 09 + 09 + 24, 09 + 12 + 24 or 12 + 12 + 24, you need an MPD 36,000 or 42,000.
ACD MPD-22 sheet, p. 4; English ACD multi-zone sheet12 + 18 + 18
Both ACD sheets publish the 12 + 18 + 18 trio for the MPD 36,000, but not for the larger MPD 42,000. The other way round, only the MPD 42,000 has 09 + 24 + 24 and 18 + 18 + 24.
ACD MPD-22 sheet, p. 4; English ACD multi-zone sheet04 · Questions
The MPD 24,000 is the smallest three-port MPD outdoor unit, with 5 published trios. The MPD 30,000 has 7 and adds 09 + 12 + 18 and 12 + 12 + 18; the MPD 36,000 and 42,000 have 14 and 15, and are the only ones to take a 24,000 head. The choice is made at the on-site assessment of your heating needs.
ACD MPD-22 and English multi-zone sheetsYes, on an MPD 36,000 or 42,000: ACD lists 09 + 09 + 24, 09 + 12 + 24, 09 + 18 + 24 and 12 + 12 + 24 for both. No MPD outdoor unit has 12 + 18 + 24, or three 24,000 heads, in ACD’s sheets.
ACD MPD-22 sheet, p. 4; English ACD multi-zone sheetOn the MPD 24,000: 60 m in total, so 20 m on average for three lines, and 20 m at most for the longest. On the MPD 30,000 to 42,000: 70 or 75 m in total, 25 m max. per line.
ACD MPD-22 sheet, p. 2; MPD manual (INS527), p. 14All four outdoor units with three ports or more have 12 + 12 + 12 on their list. The MPD 24,000 is therefore the smallest that takes it; it is also, with 09 + 09 + 18, one of the two largest trios on its list (36,000 BTU/h of heads).
ACD MPD-22 and English multi-zone sheetsPricing is by quotation, installation included: it depends on the MPD outdoor unit, the type and size of the three heads and the route of the three lines. The home estimate is free and without obligation.
AirGreen · Heating and cooling
We look at the three rooms and the line-set route, assess your heating needs on site, then send you the quote. The estimate is free.
Price on quotation; free home estimate.