I have a Potterton Prima 60F Central Heating system - simple heating system with 16 rads each with TVR so no room stat. Had problems with air in the system for a number of years. Changed the pump approx 6 months ago and since then get a kettling noise above the pump in the feed/expansion area after the system has been running for a couple of hours. I had been advised to check for blockages by placing a magnet on the suspected pipes and the magnet was attracted to the pipe in a number of spots
Added Sentinol X400 and the system ran a lot quieter with minimal air getting into the system. So I thought the X400 had cleared the problem. After flushing the system clean - and it was thoroughly flushed through the system ran well for several hours before the kettling reappeared. The kettling noise reduces when raising the pump speed to 3.
The magnet was still attracted to the same areas of pipe and so I cut out the suspect areas. The 15mm feed pipe was partially blocked in a t piece before the pump. I have replaced this with 22mm pipe thinking that would help after talking to the pump manufacturer - Circulating pumps.
I refilled the system and as normal took me ages to get all the air out of the system. After 48 hours I was pretty sure that all was well as I ran the pump with boiler off and no gurgling noises - the pump ran very quietly with a normal water flow noise in the pipes around the pump.
When I turned the boiler back on the flow noise gradually became noisier when the boiler was firing ie on it's heat cycle. I would not call it kettling more like running water mixed with air. After 4 hours this changed on the heat cycle to more like kettling for 20 seconds then died away as the boiler turned off getting up to heat
But the system is working really well with all 16 radiators getting to full heat within 20 mins with no cold spots. I bled all the upstairs radiators this morning and 1 emitted air for approx 2 seconds and 2 others emitted combined air and water for the same time.
Is it possible the system could eventually right itself or do I have other problems ?
Added Sentinol X400 and the system ran a lot quieter with minimal air getting into the system. So I thought the X400 had cleared the problem. After flushing the system clean - and it was thoroughly flushed through the system ran well for several hours before the kettling reappeared. The kettling noise reduces when raising the pump speed to 3.
The magnet was still attracted to the same areas of pipe and so I cut out the suspect areas. The 15mm feed pipe was partially blocked in a t piece before the pump. I have replaced this with 22mm pipe thinking that would help after talking to the pump manufacturer - Circulating pumps.
I refilled the system and as normal took me ages to get all the air out of the system. After 48 hours I was pretty sure that all was well as I ran the pump with boiler off and no gurgling noises - the pump ran very quietly with a normal water flow noise in the pipes around the pump.
When I turned the boiler back on the flow noise gradually became noisier when the boiler was firing ie on it's heat cycle. I would not call it kettling more like running water mixed with air. After 4 hours this changed on the heat cycle to more like kettling for 20 seconds then died away as the boiler turned off getting up to heat
But the system is working really well with all 16 radiators getting to full heat within 20 mins with no cold spots. I bled all the upstairs radiators this morning and 1 emitted air for approx 2 seconds and 2 others emitted combined air and water for the same time.
Is it possible the system could eventually right itself or do I have other problems ?
