More grrrumps with my water system

[davidivorwynphillips]

Having taken my water system apart to discover why I was getting continual grrrumps from water pump I find that I had two pressure relief valves on my calorifier. At the top is a standard domestic 3 bar one (with the red cap) and on the side an adjustable Gresswell relief valve which was leaking and the cause of the problem. I went to my local plumbing merchant and asked about the latter - "I haven't seen one of those for a long time...."
So why two pressure relief valves? I'm tempted just to go with the one standard domestic valve - any views on this??

 

[Yngmar]

Without having seen it, could one be for the freshwater and one for the coolant circuit?

 

[davidivorwynphillips]

They are both fresh water!

 

[duncan99210]

I'd blank off the leaky one, provided you're happy that the other one works.

 

[davidivorwynphillips]

That's the plan

 

[RichardS]

Sounds like someone being over-cautious in case one valve seizes in the closed position. In practice, the problem is always the opposite so your removal plan is a good 'un.

Richard