Mechanical timer on pump

[dboi78]

Went to do a boiler service today and when I checked the cylinder I noticed a pump which was on the outlet of the unvented, it was a grundfos with a mechanical timer never seen one before, I just wondered what the application of this pump was and the purpose of the timer as it already had ch pump timers and stats, the grundfos website wasn't much help, thanks in advance.

 

[SimonG]

Not a secondary return on the unvented?

 

[AWheating]

probably as simon suggested.

 

[jtsplumbing]

What colour was the pump ??

 

[kozak1968]

Grundfos do a stainless steel pump which is red in colour and often gets confused with a 15/50 central heating pump

 

[dboi78]

Grundfos do a stainless steel pump which is red in colour and often gets confused with a 15/50 central heating pump[/QUOTEit was seperate to the CH pump, having done a bit of reading it seems likely its a secondary return as previously said but it didn't have a zone valve on the dhw side I'm guessing it wouldn't need one if its controlled by a timer but could do with some more information on that,

Thanks for replies

 

[jtsplumbing]

if you understand the reason why a secondary is fitted, then it only needs a time control, why have it running through the night when no one is useing hot water, or through the day when out at work, I take it this was a large property ?

 

[dboi78]

if you understand the reason why a secondary is fitted, then it only needs a time control, why have it running through the night when no one is useing hot water, or through the day when out at work, I take it this was a large property ?

Yeah that's what I thought but needed someone to confirm, haven't had much dealings with secondary returns since college so it threw me a bit, massive house I was well jel !