Grundfos Alpha + pump/Icos He 24 boiler

[ambi]

Hi,
Have been getting intermittent kettling noise with loud banging via boiler /pipework. Boiler / pump installed about 18 months ago. Ha sbeen fine until approx 4 weeks ago. Pump is operating and was set betwen 2&3. Enginner upped speed to highest 3+. Calmed down but carried on doing it intermittently. System can be very quiet for hours and then have a mad 5/10 mins. Does not discriminate between D/H/W or C/H selections. Less of a problem on the higher speed but still a problem. Engineer came again and said he had spoken to someone that morning who told them it is a variable pump, that may be not operating correctly and to overide it. Had a look and couldn`t find anything , but before leaving to go and further research found that the pump switch clicked a further position past the no3. Said it seemed to be the position and to see how it went. It was very good and quietened things down, but had a 5 min clunk and gurgle last night so there is still something amiss. Have you guys had much problem with these energy conservant variable pumps? How many positions are selectable on them? Thoughts / experienced observations appreciated.
Regards

 

[gas4you]

Yes, the early Alpha pumps did have quite a bad reputation.

Apparently I am reliably informed that the new Alpha pumps have been improved to overcome the problems, although this info was via my local Grundfoss rep.

Wouldn't this pump have had a 2 year warranty? Have a look for a date sticker on it.

 

[ambi]

Cheers Gas. Installation under 2 yr warranty. Need for pump to be the accepted problem though!

 

[ambi]

Back on this one. Gas...Spoke to Grundfos who tell me it is only 1 yr g/tee on Alpha+ pump.

Appreciate input to this.. On the Ideal He24, when you guys install, at what position do you generally set the boiler thermostat at ( including min & max equals 6 settings? Have you come across a high boiler stat setting causing intermittent kettling/banking/clunking etc? Can it cause a form of cavitation to occur. I have lowered the stat and am monitoring it as I write, seems to be helping. Thoughts welcome?

 

[ambi]

Very surprised with all the experience on here that no thoughts!

 

[gas4you]

Unfortunately I am so over booked with work at present I do not have much time left to post on here

I usually leave the ch boiler stat set at about 12-1 O'clock position.

If I was your installer I would fit a new pump (a standard one) to see if that made any difference. If not then take it off again.

We all carry new pumps on our vans so it would not cost anything other than a bit of time.

 

[ambi]

Cheers Gas,
Thought there may be a few thoughts in general. Thanks for your input. As per prev have set stat to about 1 O`clock and at present it seems to be sounding good, but will know for sure tonight. Over past week variations of Pump settings sounds fine, right across variable range and on manual I,I & II settings with problem persisting up until lowering stat ( today). Although I personally like the water temp right up afurther notch ( 1 notch below max ) on the boiler stat. Still hot though, if that does it so be it. Do you think a high boiler stat temp could cause these problems though? Have you come across anything like it? Appreciate your time to post.
Regards

 

[ambi]

Gas, thanks for your previous input. I thought that it would be nice to give a report back for info.
Reference my problems within these posts and my last one whereby I lowered the boiler stat down to 1 O`clock position, which I have further upped to midway between 1 & 2 O`clock position today. ( half a segment now below the setting during my problems.) The problem has totally been cured and the system is running smooth and quiet and tickety boo. Thought you would appreciate feedback for info.
Regards