How to Replace a Discontinued Dometic Penguin II, Brisk II or Blizzard NXT
Posted by RV AC Guys on 22nd Oct 2026
Your Dometic AC died, and the model isn't sold anymore
If your RV has a Dometic Penguin II, Brisk II or Blizzard NXT, you may have found that the exact unit is hard to buy. Dometic's US rooftop air conditioner lineup now lists the FreshJet 5 Series, and the older models no longer appear there. The good news is that replacing an older Dometic is usually straightforward, as long as you check a few things before you order.
What replaces what
| Your old unit | What to look at |
|---|---|
| Penguin II (13,500 or 15,000 BTU, low profile) | Dometic says the FreshJet 5 15K is "backwards compatible with Penguin II models." Owners commonly match the Penguin II 640316 to the FreshJet FJX5557M, and Penguin II heat pump units to the FJX5557MHP. |
| Brisk II (13,500 BTU, about 13 7/8 inches tall) | A FreshJet 5 13.5K or 15K fits the same standard roof opening and sits lower, at about 10.5 inches. |
| Blizzard NXT | Replace with a FreshJet 5 of the same BTU rating, and match ducted or non-ducted. |
Prefer to keep the unit you have? Most repair parts for these older models are still sold, from capacitors and fan motors to control boards and shrouds. See our Dometic air conditioner parts.
Check 1: The roof opening
Almost all RV rooftop air conditioners mount over the standard 14 x 14 inch opening. Dometic specifies 14.3 x 14.3 inches, plus or minus 0.1 inch, and a roof thickness (roof to ceiling) of 1.5 to 6 inches. The FreshJet 5 15K lists a 14.17 inch cutout. If your old Dometic came off a standard opening, a FreshJet will drop onto it. You'll want a new installation gasket either way.
Check 2: Ducted or non-ducted
- Non-ducted: the AC blows straight down into the room through a ceiling assembly (air distribution box) mounted under the roof opening.
- Ducted: the AC feeds ducts in the ceiling, and a ducted ceiling kit with a return-air grille sits under the opening.
The rooftop unit and the ceiling assembly are usually sold separately, so match the new rooftop unit to your setup and budget for a new ceiling assembly if the old one won't work with it. See Dometic ceiling assemblies.
Check 3: The thermostat connection
Owners report that many older Dometic systems use an RJ11 thermostat cable, while the FreshJet uses RJ45. If you're keeping your existing wall thermostat and cable, the Dometic FreshJet 5 thermostat wiring adapter RJ11 to RJ45 (9610008210) bridges the two. If you're replacing the thermostat too, the Dometic CCC2 / FreshJet wall thermostat 9610007991 covers single-zone and multi-zone systems. Browse all Dometic thermostats.
Check 4: Power and soft starts
The FreshJet 5 15K is rated at 12.66–19.73 amps and has a built-in hard start. If you run on a generator, a soft start can cut the start-up surge a lot. Dometic sells model-specific SmartStart kits for both the FreshJet 5 mechanical and the FreshJet 5 electronic versions. Read more in our guide to RV AC soft starts and generators.
Check 5: Roof pitch and height
Dometic lists a maximum roof tilt of 15 degrees for most rooftop units, but only 8 degrees for some low-profile models such as the FJX5557M. If your RV's roof curves noticeably where the AC sits, check the installation manual before ordering.
Quick replacement checklist
- Write down the model and serial number from your old unit's label.
- Confirm BTU (13,500 or 15,000), heat pump or cool-only, and ducted or non-ducted.
- Measure the roof opening and roof thickness.
- Decide whether you're keeping your thermostat (you may need the RJ11 to RJ45 adapter).
- Order a new installation gasket.
Shop Dometic RV air conditioners, or contact us with your old model number and we'll help you match it. For an unbiased overview of the whole Dometic lineup, see RV Guidance: Dometic RV Air Conditioners.