Crown Boiler Co. · Error codes
Crown Phantom II H01 — Anti-short Cycle
H01
Anti-Short Cycle. While a thermostat demand is present the boiler cycled off too quickly and restart is delayed [01.0], or an urgent calibration cooling delay is holding the boiler until supply temperature drops below 95°F [01.1], or the flow switch was closed before the boiler pump started so the start is delayed up to 30 seconds waiting for the flow switch to open [01.2]. The boiler restarts automatically after the minimum off time (default 3 minutes). The table classifies it as Hold / Warning.
Applies to
This fault code is displayed by the Phantom II control (H01–H32 / E04–E29 codes) on Phantom II models (PHTM2080H, PHTM2120H, PHTM2150H, PHTM2180H, PHTM2136C, PHTM2200C), as documented in Phantom II Heat-Only Installation and Operation Manual, doc 110332-07 (9/25) (110332-07). Codes can differ between controller generations, so always check the manual that matches your unit.
- Crown Boiler Co. Phantom II
- Crown Phantom II PHTM2080H
- Crown Phantom II PHTM2120H
- Crown Phantom II PHTM2150H
- Crown Phantom II PHTM2180H
- Crown Phantom II Combi PHTM2136C
- Crown Phantom II Combi PHTM2200C
Controller: Phantom II control (H01–H32 / E04–E29 codes). Source manual: 110332-07 (2025-09).
Why a code is not a diagnosis
The code reports the condition the control detected; the underlying cause must be confirmed on site by a licensed technician using the manufacturer's procedure.
Safe things to observe
- Note the exact code, when it appears and what the appliance was doing.
- If the appliance has stopped, call a technician rather than repeatedly restarting it.
- If you smell gas, stop, go outside and call your gas utility's emergency line or 911 before anything else.
Do not
- Do not ignore a code that returns after a reset.
How professional service helps
- A licensed technician diagnoses the cause with the manufacturer's test procedure.
- 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.
Parts and service
Parts commonly involved
These parts appear in the documented text for this alert. A code reports a condition, not a failed part — a technician confirms the cause by testing before anything is replaced.
Flow switch
A flow switch proves that water is actually moving through the boiler before it fires and while it runs.
What a technician checks →Circulator pump
The circulator is the pump that moves heated water from a boiler out to the radiators, baseboards or in-floor loops and back again.
What a technician checks →
Service for this alert
- Gas Boiler Repair
Licensed gas technicians from ROMA Heating & Cooling diagnose and repair residential and light-commercial gas boilers across…
Every boiler part explained — what it does, how it fails and what a technician checks.
Documented for Crown Boiler Co. Phantom II.
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
- Phantom II Heat-Only Installation and Operation Manual, doc 110332-07 (9/25) · 110332-07 · accessed September 8, 2026
Facts checked September 8, 2026. Last updated September 8, 2026. Technical reviewer: not yet assigned.