The boiler was installed Nov 2006. It has not been professionally serviced.
Mmm, two things. First, I have serviced the boiler several times in the past myself and found things quite clean, but accept it might just be possible they have suddenly become dirty.
Secondly, since asking my question above, I have tried slowing the pump speed to minimum, and shortly within 20 mins the red fault light lit and Fault code 26 showed on the display:(Maximum delta t). What does this suggest -the pump is still operating. It has never occured previously when the pump speed was set lower. How can I check or increase delta t (set too restrictively)?
What I am trying to achieve with my question is to identify accurately what the fault is likely to be, so I can get it fixed directly.
OK. How long should a Grundfos UPS2 15-50/60 pump last in a domestic situation? I replaced the last one after 4 years about 4 years ago because it sounded to have worn bearings - rumbling. The present one has been getting noisy for nearly 2years and I was going to replace it shortly anyway. I wouldn't have thought the cast metal impeller or housing wouldn't wear that much, but the bearings maybe?
Anyway, do you believe that if I change the pump it will likely rectify the problem in my original question?
Also, do you know if and how it is possible to check/ vary 'delta t'?
These new boilers are all very well but I have spent most of the fuel savings since it was installed on parts and maintainance keeping it running properly. The old one was 40 yrs old and v few probs until the end!
I will replace pump and get it cleaned / serviced and see where we are then.
Do I find you again here at 'just Answer UK', or other wise?
Replaced pump and boiler now working perfectly, modulating at 70C set point. Cheers.
Wonder if this pump will last longer than the 4 years when the previous two became un serviceable?