Circulating pump for Multi zone?

[Beano10]

Hi guys, I’m in the process of ripping out an old one pipe system and replacing it with a two pipe, feed and return. The new system will be on two zoning valves one for upstairs and one for downstairs.

Originally i wanted the system on a single stat and single zone valve... with a flow of 0.477 l/s and a 3.9m head loss (excluding loss over the boiler) I was going to use the Grundfos Alpha 1 as I liked the idea of balancing the system from the mobile app (potentially a time saver) and the option of auto adjusting flow rate as the TRVs close.

I’ve since changed my mind to a multi zone with upstairs and downstairs on separate zone valves and wondered if the same pump would be able to adjust flow automatically when the zone valves close.

If I go with the two zones, at the pump the flow is still 0.477 l/s but of one zone valve closes, the upstairs loop has a flow of 0.22 l/s with 1.5m head (excluding boiler) and the downstairs loop has a flow of 0.25 l/s with a head loss of 2.1m. Would the alpha 1 be able to reduce the flow rate enough to keep the return temp to the boiler the same no matter which valves are open or closed?

Thanks

 

[king of pipes]

Providing its is piped correctly then yes . Kop

 

[Gasmk1]

why not go wiyh low loss header vaillant boiler and the vailalant controls rally easy to multizone

 

[gmartine]

A typical situation where hydraulic seperation is required, close couple tees would probably do it though don't you think Gm1?

 

[Beano10]

Thanks for the replies...

In terms of piping it's a vented S-plan system with a 24kW Worcester Greenstar Ri boiler. There's a bypass (gate valve) fitted which I hoped would maintain flow when the zone valves close.

I was hoping to add an additional zone valve in parallel with the existing CH valve? Would I need a low loss header/close couple tees for this to work?