Hi
I have a CH system in our house (10 yrs old from new) 18 rads, fully balanced, Grundfoss 15/60 pump set on speed 3, open vented.
System is spotlessly clean inside, has been flushed twice & drained in past ten yrs, always treated with fernox.
Rads were balanced a couple of yrs ago, I also confimed the temp differential accross the flow/return of the boiler is 20C at max modulation. I had the CO2 checked by my central heating fitter buddy, we replaced the burner gaskets with graphite ones and everything was spot on, clean as a whistle inside & the condensate trap is also clean n leak free.
Basically the system works fine, I set the boiler temp at around 68C and I checked the return temp to ensure it's running in condensate mode when the CH's on and it is.
The only problem I have, is that sometimes when the boiler fires up, on demand from either the HW or CH it makes a kind of shuddering noise for about 2-3 seconds which is quite loud, after that it seems to be fine, runs quietly & modulates correctly.
Any ideas ???
Thx
I have a CH system in our house (10 yrs old from new) 18 rads, fully balanced, Grundfoss 15/60 pump set on speed 3, open vented.
System is spotlessly clean inside, has been flushed twice & drained in past ten yrs, always treated with fernox.
Rads were balanced a couple of yrs ago, I also confimed the temp differential accross the flow/return of the boiler is 20C at max modulation. I had the CO2 checked by my central heating fitter buddy, we replaced the burner gaskets with graphite ones and everything was spot on, clean as a whistle inside & the condensate trap is also clean n leak free.
Basically the system works fine, I set the boiler temp at around 68C and I checked the return temp to ensure it's running in condensate mode when the CH's on and it is.
The only problem I have, is that sometimes when the boiler fires up, on demand from either the HW or CH it makes a kind of shuddering noise for about 2-3 seconds which is quite loud, after that it seems to be fine, runs quietly & modulates correctly.
Any ideas ???
Thx