Honeywell ABV setting

[ShaunCorbs]

There for limiting water flow eg cold and hot

Won’t be any good on heating and will short circuit as always open

 

[John.g]

They claim +-15% accuracy at the lower pressures but maybe this is only if one side (end) is open like a tap etc?.
https://renergise.ie/wp-content/uploads/2014/07/In-Line-Flow-Regulating-Valve-Brochure.pdf

 

[decomplexity]

I have just emailed Cottam and Preedy to ask if there are technical (or duty cycle) reasons why usage should be confined to DHW - such as (as John.G says) the downstream end being 'open'

 

[doitmyself]

Grundfos recommend the Taconova "Setter" valve if a fixed flow rate is required.

 

[John.g]

Yes but the "wondervalve" above claims that it will (or might) maintain a fixed flow with a varying pump head as will occur with PP operation. The setter valve is recommended for a pump on a CP (constant pressure) setting but the flow would vary in pump PP mode?.

 

[decomplexity]

Grundfos's note (attached) on their newish Alpha2 pumps and ABVs in CP and PP modes is worth a look. The parting comment there (for PP mode) is that "If an automatic bypass valve must be used, then a manual fixed bypass valve should be installed in series with the automatic bypass valve. The fixed manual bypass will restrict the flow as the automatic bypass valve opens."

 

[John.g]

Grundfos's note (attached) on their newish Alpha2 pumps and ABVs in CP and PP modes is worth a look. The parting comment there (for PP mode) is that "If an automatic bypass valve must be used, then a manual fixed bypass valve should be installed in series with the automatic bypass valve. The fixed manual bypass will restrict the flow as the automatic bypass valve opens."

I don't see any advantage in having a ABV+fixed bypass over a fixed bypass alone. See my post #10.
The wondervalve may improve this again, it will be interesting when/if they reply to your email.

 

[decomplexity]

Agreed - I found their argument a bit strange. It appears that the only circumstance where a differential pressure driven ABV would be effective is where the pump has a monotonically decreasing head from zero flow onwards. And none of Grundfos's domestic pumps have this as far as I know.

 

[Riley]

There for limiting water flow eg cold and hot

Won’t be any good on heating and will short circuit as always open

Or just completely ignore you