Corrision / Pump Speed?

Please take a look at the photo. the Grundfos 15-50 UPS is fitted in a 3 bed house with an Ideal Elan Minimiser SE60 condensing boiler. All rads are new (last 3yrs).

I'd like to know
a) is the crusty blue build-up normal - to me it looks like the isolation valves may be leaking.
b) what speed should be used for the pump? It's on 2 at the moment. Will the house get warmer faster if it is set to 3?
c) how long do these pumps last? We've been here 17 years and it was present (in a similar state) when we moved in?
d) what rust inhbitor should be used? We like in a hard water area

Thanks

BarkingMadBarking View media item 6570

a)
to me it looks like the isolation valves may be leaking
but
been here 17 years and it was present (in a similar state) when we moved in.
So wipe the crust off with a damp brush or rag, leave it alone and keep an eye on it.

b) 2 might be enough but 3 might be needed, depending on your pipe sizes. Key thing - while the radiators are heating up from cold, does the boiler cut off and on? If so , use speed 3.

c) 17 years and 3 days... Have known then last 30 years. ANd 1 year, too.

d) Pour say Sentinel X100 in the header tank, and forget it, unless there's a problem. Clean 17 year old systems tend to stay clean.

Thanks for the reply.

I'll try removing the residue and see how fast it re-appears.

On fire up from cold, the boiler does run for 15-20 mins before deciding to have a rest. I thought the boiler had sensors on the input / output pipes and when a differential of around 10 deg C was reached then this would trigger a cut-out. Are there other sensors that detect the overall temperature in the exchanger and decide to shut-off the burner if th water flow is not great enough?

The whole system was drained about 2 years ago because we had building work. I don't think the plumbers put any inhibitor when it was refilled. I read somewhere I could get a nail and then take some water from the tap and the heating system and see if the nail rusts.

I disagree with ChrisR. My response,

a) One isolation valve has a tiny weep on it but the main leak looks to be the pump washers.

b) If all the rads heat up ok on speed 2 then speed 2 is fine and nothing other than additional noise and electriciy usage will be gained by turning the pump to speed 3.

c)The pump you have a good pump. it might last another 17 years it might stop working tomorrow.

d)Pouring x100 into the header tank is pretty much a waste of time. it could take 17 years to find its way into the system in which case yo have achieved nothing!! It wants to be injected into a radiator or put in at the time of system filling.

My advise would be to clear the verdigre off the pump isolation valves, remove the pump and rewasher it using rubber washers.

Add inhibitor via a radiator if you so choose and leave the pump on speed 2 if the system works ok.