Sudden pressure loss in ASHP system

[kandgmitchell]

Hi,

I've a Vaillant Arotherm heat pump system that's been in and working for about 18 months. During that time we have experienced 3 cases of total loss of pressure in the system. The last was whilst we were away abroad last week and I had to talk my daughter through topping up the system using the filling loop, and re-setting the pump- isn't WhatsApp wonderful!

 

There is no water in the tundish and the loss is sudden not a gradual creep. This suggests there isn't a leak in a loop because one would expect the pressure to degrade over time. It's almost as if the system is initiating an irregular process that involves using a particular valve or suchlike which when used, dumps the pressure and causes the system to shut down.

 

I am about to start the process of taking this up with the installer but thought I would put the problem out there so I can approach them with a bit more knowledge.

[SimonD]

Have you checked the anti-freeze valves? Big puddle of water around them?