Question 1

The fluid level in the expansion tank keeps dropping while filling or bleeding

Accepted Answer

Possible cause: Air is being expelled from the system and fluid is filling empty cavities and pipework. Top up the fluid level in the expansion tank to 30 mm above the MAX mark and continue the procedure.

Question 2

Bubbling and gurgling noises during filling and bleeding

Accepted Answer

Possible cause: Trapped air is being pushed out through the expansion tank and the boiler's automatic air bleed valve.. This is normal operation. Continue to cycle the pump and monitor the fluid level until no large bubbles are visible in the clear braided hoses.

Question 3

Rumbling noises occurring during system bleeding

Accepted Answer

Possible cause: A large amount of trapped air is moving through the system. Continue cycling the pump while closely attending the fluid level, and bleed air manually from system bleed points as per the boiler instructions.

Error Code / Indicator	Symptom / Meaning	Possible Cause	Step-by-Step DIY Fix	Suggested Actions
`N/A`	The fluid level in the expansion tank keeps dropping while filling or bleeding	Air is being expelled from the system and fluid is filling empty cavities and pipework	Top up the fluid level in the expansion tank to 30 mm above the MAX mark and continue the procedure.	DIY Safe
`N/A`	Bubbling and gurgling noises during filling and bleeding	Trapped air is being pushed out through the expansion tank and the boiler's automatic air bleed valve.	This is normal operation. Continue to cycle the pump and monitor the fluid level until no large bubbles are visible in the clear braided hoses.	DIY Safe
`N/A`	Rumbling noises occurring during system bleeding	A large amount of trapped air is moving through the system	Continue cycling the pump while closely attending the fluid level, and bleed air manually from system bleed points as per the boiler instructions.	DIY Safe

Alde 1900811

Technical Specifications

Master Troubleshooting & Diagnostics Matrix