KeepRite is the Canadian label on furnaces built by International Comfort Products, which also badges the same chassis as Tempstar, Heil and Comfortmaker. If you have one of those instead, this page still reads true — they are the same equipment sold through different dealer networks, and the diagnostic legend follows the platform rather than the badge on the door.
What does not follow is Carrier. ICP has sat inside the same corporate family as Carrier for years, and homeowners reasonably assume the code charts interchange. They do not. The two use different legends, and even the resting behaviour of the diagnostic light differs, so a count that means an open limit on one can point somewhere else entirely on the other. Reading a Carrier chart against a KeepRite furnace is one of the more common ways people end up replacing a part that was never faulty.
Find the light through the sight glass on the lower door, count the blinks in one group between pauses, and check that count against the diagnostic label inside the blower compartment of your own unit. That label is the authority and it is model-specific — where this page disagrees with it, follow the label. If the furnace is off and the house is getting cold while you decode it, our KeepRite page covers what we stock and ZK Mechanical picks up the emergency line at any hour.
KeepRite furnace codes, decoded
| Code | What it means | Safe? | Try first | When to call |
|---|---|---|---|---|
Slow steady blink | Normal standby. The control is powered and holding no fault. | keep running | Nothing required. | Only if the furnace is not heating despite a normal light. |
Dark light | No power at the control, an opened fuse, or a door switch that is not being made. | turn it off | Seat the lower panel firmly, then check the service switch and the breaker. | If all three are fine and nothing lights up. |
Rapid continuous blink | On many ICP controls this indicates line polarity reversed or a missing ground. | turn it off | Nothing at the furnace. The problem is upstream at the receptacle or panel. | Yes — the flame sensing circuit cannot function without a proper ground reference. |
Lockout after failed trials | The control ran its permitted ignition attempts, never proved flame, and locked out. | turn it off | One reset at the switch is fair. Expect the flame sensor or igniter to be behind it. | If it locks out again. Do not keep cycling it to get through the night. |
Pressure switch did not close | The inducer started but draft was never proven, so the gas valve stayed shut. | turn it off | Check outside for blocked or drifted-over intake and exhaust terminations. | If the vents are clear — suspect the condensate trap, the tubing or the inducer. |
Pressure switch stuck made | The switch was already closed before the inducer ran, which fails the control's safety check. | turn it off | Nothing safely serviceable at home. | Yes. A switch that cannot open is a failed safety device and must be replaced. |
Limit circuit open | A high limit opened because the furnace exceeded its safe operating temperature. | turn it off | Change the filter and open every register before restarting it. | If it recurs with clean airflow — the cause is restriction, not the switch. |
Rollout switch open | Flame or hot gas escaped the burner box and the rollout cut the gas supply. | call now | Nothing. Leave the manual reset button alone. | Immediately, and keep the furnace off until it has been inspected. |
Flame present out of sequence | Flame is being sensed when the control has not called for gas. | call now | Switch the furnace off at the service switch and leave it off. | Immediately. This is a gas valve or sensing fault, not something to observe for a while. |
Weak flame signal | Flame proves, but the current is low enough that dropouts are coming. | keep running | Schedule maintenance while it is still heating reliably. | On your own timeline, before the season turns. |
Blower not confirmed | The control cannot verify the circulating blower is running as commanded. | turn it off | Note whether you hear a hum with no airflow, and pass that on. | Yes. Firing without confirmed circulation leads straight back to limit trips. |
Inducer speed not proven | The combustion-air inducer spins, but not at the rate the control needs to see before it will permit ignition. | turn it off | Nothing serviceable at home. Write down any grinding or rattling you have noticed. | Yes. A dragging inducer reads at the board as a pressure switch problem soon enough. |
The codes that usually mean a real repair
The wrong chart, the wrong part
The repair we see most often on KeepRite furnaces is the one that already happened before we arrived: a part swapped because someone matched the blink count to a Carrier or Goodman table. Nothing about the count transfers between manufacturers. We read the legend on the unit in front of us, confirm the fault with a meter, and only then quote — which is why a diagnostic visit runs $90–$150 and gets folded into the repair when you proceed.
Ignition faults on ICP platforms
Failed ignition on these furnaces resolves to a short list: a flame sensor that has oxidised, a hot surface igniter at end of life, or gas pressure that is not what the rating plate expects. All three sit inside the $150–$450 band we quote common repairs in, and the trucks carry sensors and igniters for the ICP platforms because Tempstar, Heil, Comfortmaker and KeepRite all draw from the same parts pool.
Snow, sidewall vents and pressure faults
High-efficiency KeepRite furnaces vent through the sidewall, and in Burlington, Waterdown and up on the Hamilton Mountain those terminations disappear under drifted snow more often than anywhere else we work. The furnace reports a pressure switch fault and the homeowner reasonably assumes a broken part. Clearing and re-terminating at the right height is frequently the whole repair — see what to do when a furnace vent is blocked by snow.
Licensed technicians, trucks stocked with KeepRite parts, no overtime charges.
Common questions
Is KeepRite the same as Tempstar or Heil?
Structurally, yes. All are International Comfort Products brands built on shared chassis and controls, sold through different dealer channels. Diagnostic behaviour and most parts cross over, which is why availability is generally good even on a brand some homeowners have not heard of.
Can I use a Carrier code list on my KeepRite?
No, and this is the important one. Despite the corporate connection, the two use different diagnostic legends and their lights behave differently at rest — the Carrier numbering is set out on the Carrier furnace code guide and it does not transfer. Matching a KeepRite blink count against a Carrier chart is how people end up buying a part that was working fine. Use the label inside your own furnace.
Where exactly is the diagnostic light?
On the integrated control board behind the lower access panel, usually visible through a small sight glass so you never need to open the door. Count the blinks in a single group, wait for the pause, then count again to confirm — one miscount puts you on the wrong row.
Is a KeepRite furnace worth repairing?
Usually, yes. The equipment is competent mid-market Canadian-market gear and parts are readily available. The calculation shifts if the furnace is past fifteen years and the repair is a major component, because a new high-efficiency unit installs in the $4,500–$7,500 range with a fresh warranty and lower gas use. We give you both numbers and let you decide.
What if the code disappears before the technician arrives?
That is fine and quite common — a power interruption clears the display. Faults are typically retained in the control's memory and can be pulled during the visit, and we also ask what the furnace was doing when it stopped. Write down the count you saw and roughly when it happened; that detail is genuinely useful.