HTP Elite Ultra CONFL — Cascade Boilers Share a Common Address
CONFL
Cascade boilers share a common address. Incorrect settings (two or more boilers in the cascade have the same address - check menu 0.4.6 and ensure each boiler has a unique address); BUS connection shorted (the control has sensed a short circuit on the BUS connection - disconnect the field wiring from the BUS connection and confirm wiring); incorrect bus wiring (bus wiring is polarity sensitive - ensure the T connection on each cascade boiler is connected to every other T and B is connected to B); if the problem persists replace the main control. The table classifies it as Blocking (AUTO Reset).
Applies to
This communication or network fault code is displayed by the ELU control (group fault codes) on ELU models (ELU-85WBN through ELU-199WCN), as documented in Elite Ultra (ELU) Installation Manual (Table 32 fault codes), 420010970305 / LP-700 (1.24.23) — 150/199 sizes in 420011303900 (420010970305 (LP-700)). Codes can differ between controller generations, so always check the manual that matches your unit.
- HTP Elite Ultra (ELU)
- HTP ELU-85WBN
- HTP ELU-120WBN
- HTP ELU-120WCN
- HTP ELU-150WBN
- HTP ELU-150WCN
- HTP ELU-199WBN
- HTP ELU-199WCN
Controller: ELU control (group fault codes). Source manual: 420010970305 (LP-700) (2023-01).
Why a code is not a diagnosis
A communication code involves the link between controls (cascade, remote, sensors on a bus). Another unit being off, a wiring fault or an address conflict can all produce it.
Safe things to observe
- Check that every appliance in a multi-unit plant has power.
- Report the code together with any other codes on the system.
Do not
- Do not re-address or rewire control networks yourself.
How professional service helps
- A technician verifies power, wiring and settings across the connected units.
- Combustion and safety devices are verified with an analyser and the manufacturer's procedure after any repair.
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
Can I clear this code myself?
Clearing a code without fixing its cause usually just brings it back. Note the code, check the safe items on this page, then call a licensed technician. If your appliance manual describes a user reset for this exact code and it stays away, no call may be needed.
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
- Elite Ultra (ELU) Installation Manual (Table 32 fault codes), 420010970305 / LP-700 (1.24.23) — 150/199 sizes in 420011303900 · 420010970305 (LP-700) · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.