IBC Technologies · Error codes
IBC SL G3 “Interlock open” alert
Error: Interlock [1 or 2] Open
The manual lists this alert when an interlock circuit wired to the boiler's low-voltage terminals is open. That is either the factory jumper lead on the interlock terminals being loose or compromised, or an external safety device connected to the interlock circuit being in its alarm state.
Applies to
This alert is shown by the V-10 touchscreen controller on SL Series G3 residential boilers (SL 10-85 G3, SL 14-115 G3, SL 20-160 G3 and SL 30-199 G3), as documented in IBC Installation & Operating Manual — SL 10-85 G3 / SL 14-115 G3 / SL 20-160 G3 / SL 30-199 G3, doc 120-276E13, sections 9.2–9.4.
Controller: V-10 touchscreen controller. Source manual: 120-276E13 (2026-08-11).
Why a code is not a diagnosis
An open interlock is a signal, not a diagnosis: the boiler cannot know whether the open circuit is a loose jumper, a tripped external safety (for example a flow switch, leak detector or building-management interlock), or damaged wiring. Each interlock connected on site must be inspected in turn.
Safe things to observe
- Read the alert text and note whether it names interlock 1 or interlock 2.
- Think about what has changed recently: maintenance work, a new zone, a pump change or another trade working near the boiler.
- Check that the boiler's own service switch is on and that no visible alarm is showing on any external safety device wired near the boiler.
Do not
- Do not jumper or bypass an interlock circuit to make the boiler run.
- Do not open the boiler cabinet to inspect the low-voltage terminals yourself.
- Do not ignore the alert if the interlock is connected to a safety device such as a leak or flow switch.
How professional service helps
- A technician verifies the factory jumper lead on the interlock terminals and replaces it if damaged.
- Every external safety device on the interlock circuit is identified, tested and reset only when it is safe to do so.
- The boiler is returned to service only once the interlock circuit closes for the correct reason.
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Frequently asked questions
What is wired to the interlock on my boiler?
It depends on the installation: many boilers run with only the factory jumper, while others have external safeties such as a flow switch, low-water cutoff or building interlock connected. Your installer or a service technician can confirm what is on yours.
Can I reset this alert myself?
The manual does not list a homeowner reset for an interlock alert; a technician should confirm why the circuit opened first. If an external safety device tripped, it must be investigated, not cleared.
Boiler locked out? Call with the alert text ready.
The brand, model and this alert are passed along when you request service online, so the technician arrives prepared.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
- IBC Installation & Operating Manual — SL 10-85 G3 / SL 14-115 G3 / SL 20-160 G3 / SL 30-199 G3, doc 120-276E13, sections 9.2–9.4 · 120-276E13 · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.