Following on from the previous brilliant post "breaker type".

I started to wonder about a recent event where I on a Friday was called to a specialised "Controlled Environment Cold Store"
This very neat install was supplied, Installed and is remotely monitored by a Dutch Company "Reftech".
Anyone heard of them?

My brief was to arrive at the Lab's collect a replacement 3ph chilled water pump from the stores and fit it as over the previous week it had been tripping out frequently.

On arrival and prior to collection of the pump I decided to check out the original.
The pump is a small 3ph with a overload scale of 1 to 1.6amps.
Which was pulling a stable 0.8amps with the overload set to 1amp.
Luckily the installation's electrical drawings were available and the designed pump amperage was 1.23amps.

I then advised the customer that as the trip was set to 1a and the motor was pulling 0.8a. I felt these were to close. Recommending that the overload was reset to 1.3a.
I then spoke to the Dutch companies technician who agreed with my assessment. Thanking me for not just changing the pump. (which had yet to arrive in the stores).
I left a happy man!!
On the Monday the site phoned in saying that the pump had yet again been tripping over the weekend.

I was asked to return and change the pump. After a 1.5hrs in a 3ft roof void above the cold store I changed the pump.
On turning the pump on the site engineer with me remembered that there was a remote valve yet to be turned on.
When he turned this on there was no noticeable pitch change in the pump which was pulling a steady 0.7a across each phase!
When I checked the system water pressure (gauge within the chiller upon roof). It was at 1bar and the design pressure should be 2.25 bar.
When re pressurised the pump amperage was still at 0.7a.
Therefore I made the assumption that neither pump was faulty and the real problem had been low system pressure.
When I expressed this to the Dutch Guys they disagreed!
So shut up but did explain to the end user the importance of monitoring the system pressure.
Adding that if it continued to trip then logically the overload would need to be looked at!
What does anyone else think?
Also what the guys discuss in the faulty breaker post could it be relevant here?
Grizzly.
Thanks for your patience!!!