Flow rates through 2 and 3 port valves.

[Bogart]

Yes it me again with another question. I keep reading that one will get a better flow rate in an S plan than in a Y plan. Now I can see that being valid if both heating and hot water are called for but if only one surely the flow rate will be the same for both plans?
Finally are there any makes of 3 port valves that have bigger orifices than others to possibly negate the fact that the flow is having to go in 2 directions if in mid position?

 

[ShaunCorbs]

How much flow do you need as tbh never had a hassle with either ?

 

[hometech]

Don't just guess..it's pointless..use maths...here, it's already done for you....your welcome

Flow-rate and pressure-drop Simulator – John Cantor Heat Pumps

Flow-rate and pressure-drop simulator. Very handy pipe sizing and learning tool for assessing water pipe sizes. Copper and plastic.

heatpumps.co.uk

 

[SimonG]

3 port is more restrictive but not to the point of causing issues.

I much prefer 2 ports.

 

[Bogart]

Don't just guess..it's pointless..use maths...here, it's already done for you....your welcome

Flow-rate and pressure-drop Simulator – John Cantor Heat Pumps

Flow-rate and pressure-drop simulator. Very handy pipe sizing and learning tool for assessing water pipe sizes. Copper and plastic.

heatpumps.co.uk

Easier said than done. Over 90% of my pipework is hidden inside walls. The main pipework enters the wall at 28mm and returns at 28mm what happens to it in between is well a unknown factor.

 

[Bogart]

The total radiator output, in theory, is around 25kw, the boiler is rated at 35kw but being an old oil fired one the efficiency is not brilliant but the 3 port valve seemed to handle what was asked of it.
It was in a sorry state when I removed it on friday. My question on flows was purely out of curiosity.

 

[Bogart]

Final question on this type of topic, I promise. Is there any reason a Honeywell V4073A cannot be replaced by a V4044C? I realise the V4044C does not do a mid position and only uses 3 wires as opposed to 5. I am assuming with no power the HW circuit is open and with power it switches to heating open.

 

[Basher]

Other than, if you use more than a tankful of hot water in a day, you may have cold hot water for a bit, or cold radiators for a bit, depending on the priority set 🤪

 

[Bogart]

That will be okay I only have a bath twice a year.👍

 

[Ben-gee]

Whether you need it or not!

 

[Bogart]

Whether you need it or not!

Yes I am extravagant in that respect!

 

[hometech]

Easier said than done. Over 90% of my pipework is hidden inside walls. The main pipework enters the wall at 28mm and returns at 28mm what happens to it in between is well a unknown factor.

so if you can't see it then you can't measure it then you can't control so this conversation is purely anecdotal

 

[Bogart]

What am I trying to measure?

 

[hometech]

What am I trying to measure?

flow rate was the question right!

 

[Bogart]

Was not wanting a quantitative answer just a qualitative one out of curiosity.

 

[hometech]

flow is always a value not a theory

 

[Bogart]

Think we are going around in circles now.

 

[hometech]

Think we are going around in circles now.

well, left or right LOL