On Tue, 9 Dec 2003 15:14:59 -0000, "BillR" wrote:

Moonshine wrote:
It's that time of year when one's thoughts turn to the smoothe
running of ones CH system (sad isn't it!)

Before I go into all the details I'd just like to get some expert
opinion on the suitability of the the UPS 15-50 in my system.

The pump has been running for years on the medium setting, but I've
always been concious that the system didn't seem to be running right.

The radiators were not piping hot to the touch, the house didn't feel
warm all over, and the boiler does a lot of 1-2 minute cycling.

Turning to this group again over the last week or so for some tips,
I've treated myself to an IR themometer to do some proper
investigation.

As I say at the moment I won't go into all the figures, but the info
seemed to sugest that the pump needed to be on maximum. I've been
running it like that for a few days and things do seem to have
improved regards balance of heat even running all the LSV's open
until I'm sure what the state of play is.

My main concernes at the moment are I never see anywhere near 80
degrees C at the input to the radiators, the boilier is cutting out
when the ouput has reached this temp. The max input to closesest rad
to pump is around 70 and the lowest is around 65. And the Boiler is
still short cycling.

So before I try and rectify anything balancing like crazy I want to
know if the UPS 15-50 is powerful enough or not.

I don't know this pump, what head rating is it?
I had similar situation for many years inc boiler kettling at times.
When I changed the pump for the second time I went for a beefer pump with a
6m head.
It runs a lot quieter on its medium setting and the system works much better
too.

Hi Bill

The 15-50 is rated at 5m head.

The annoying thing is I'm sure I fitted this myself soon after moving to the
house because the existing (non Grundfos) pump was very noisy. I no longer have
it to check what the rating was, but I'll pop round a neighbours and see what
theirs is.

Is a 15-60 going to be sufficient of an improvement?

I did flush out and Fernox the system a couple of years ago, but I don't know
how good a job that would have been rated as.

Cliff