

CellarCool Ad2: the coil was still frozen when defrost timed out
Ad2 on a CellarCool Ceiling Mount, split or Ultimate unit records an Anti-Frost cycle that timed out.
Mon–Sat, 8am–8pm
- Coil icing and defrost
- Cellar coil icing and defrost repair
- Source: CellarCool
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What Ad2
actually means.
Ad2 on a CellarCool Ceiling Mount, split or Ultimate unit records an Anti-Frost cycle that timed out. Ice is forming faster than the cycle clears it, which points to dirty filters or coils, blocked air, a stopped evaporator fan, a low refrigerant charge or an exhaust space colder than 60°F. CellarCool also names long nonstop running and a setpoint too cold for the room as causes of icing.
CellarCool wine cellar cooling unit display
What to do when Ad2 shows on the wine cellar cooling unitKind of codeCoil icing and defrost
The controller found the evaporator coil too cold for too long, or a defrost cycle that did not finish. Ice grows when warm, moist air keeps arriving and the coil cannot shed it: a set point pushed too low, a blocked return, a slow evaporator fan, a low refrigerant charge, or a door that lets the house in. When the ice melts all at once it can overwhelm the drain, so a leak often follows. Switching the unit off to thaw buys time; finding why it iced is the repair.
Usually leads toCellar coil icing and defrost repair
Stopping ice from forming on the cellar coil by finding what starves it, whether airflow, charge, controls or humid air coming into the room.
Shows up asCellar Cooling Evaporator Coil Icing Up
A cellar cooling coil icing up shows as white frost behind the cellar-side grille, weak air from the unit, water dripping when it goes quiet, and a room that warms while the unit keeps running.
MakeCellarCool
Service for CellarCool systems when the wine room drifts warm, turns dry or the unit starts and stops every few minutes.
SourceCellarCool CM2500 (Ceiling Mount split) manual, version 4 (02/2022)
CellarCool split, Ceiling Mount and fully ducted Ultimate controllers (CM2500, 3500-S/5000-S, Ultimate-R manuals). The CX through-the-wall series does not list this code.
Before you book,
in this order.
Each step comes from CellarCool's own guidance for Ad2 on its wine cellar cooling units. Follow it to the end: the last card says whether this is a visit.
Check the evaporator for ice; unplug the unit and let it thaw, with towels to protect racks and floor.
Clean the filter and make sure supply and return air are not blocked.
Raise the setpoint if it was set unusually cold.
If Ad2 comes back or the unit enters Anti-Frost about once a minute, book a visit.
Still there?
It usually turns into cellar coil icing and defrost repair. Book with the code and the model number.
What not to do
Ad2 is not the ordinary defrost display, which is routine. It is logged in the alarm folder only when a defrost fails to finish.
What you may
notice with it.
The wine cellar cooling unit problems Ad2 tends to arrive with. Answer these at the wine cellar cooling unit before anyone is booked.
All problemsWhere Ad2 usually leads
Cellar coil icing and defrost repair.
CellarCool
wine cellar cooling units.
Service for CellarCool systems when the wine room drifts warm, turns dry or the unit starts and stops every few minutes.
CellarCool wine cellar cooling unit repair
Through-the-wall cellar cooling unit
A self-contained box set into an opening in the cellar wall: its cold face blows into the wine room, and its warm face breathes out into the room next door.
Ducted cellar cooling unit
A self-contained cooling unit placed outside the cellar, in a mechanical room, attic or basement, that sends chilled air in and takes return air back through insulated ducts.
Split-system cellar cooling
An evaporator inside or beside the cellar and a condensing unit outside or in another room, joined by an insulated copper line set and charged on site.
In CellarCool's own words
The Anti-Frost Cycle ended on time-out
Every code on this site is taken from the manufacturer's documentation, never from a forum or a parts listing. CellarCool split, Ceiling Mount and fully ducted Ultimate controllers (CM2500, 3500-S/5000-S, Ultimate-R manuals). The CX through-the-wall series does not list this code.
CellarCool Ad2 wine cellar cooling unit repair,
where we come out.
The same visit in every metro below: the code, the model number, and a diagnosis before any part is ordered.
All service areasTampa BayFL · 31 areas
Miami / South FloridaFL · 47 areas
New York MetroNY · 75 areas
HoustonTX · 36 areas
ChicagoIL · 50 areas
Los AngelesCA · 95 areas
San DiegoCA · 31 areas
Questions
about Ad2.
Can I clear Ad2 myself?
What should I do with the melt water when thawing a CellarCool?
Can a very low setpoint cause Ad2 on a CellarCool?
Does the CellarCool CX log Ad2?
Back to your everyday
Still showing Ad2?
When you book, type the code or the blink count as the controller shows it, add the full model number, and say what the thermometer in the cellar reads now — that gives the technician a head start.