Effective bore of 3 port valve

[mike ring]

I'm thinking of replacing my HW tank over the summer, and upgrading some central heating pipes.

I wanted to raise the primary flow and return to 22mm, and tee off the branches in 15mm, to improve overall flow.

However, in a bit of a crisis over the winter, I had to replace my 3 port valve, and looking at the works of the new one (Danfoss HSV3 with 22mm ports, but 15mm pipe connected), it seemed to me that the actual apertures the fluid goes through were pretty tiny, praps less than 15mm.

Is there any advantage then to using 22mm pipe to connect to it, with what looks like a pretty effective flow restrictor in the valve?

Or is there such a thing as a full bore 3 port valve?

Info appreciated

mike r

[G&M]

Yep. It's called a pair of 2 port valves.

[Andy Hall]

I used 2 port ones - there are types with a rotating shoe which are effectively full bore - and used 28mm types as well.

.andy

To email, substitute .nospam with .gl

[mike ring]

Andy Hall wrote in news: [e-mail]:

That sounds like a good idea, I've had a quick gander at honeywell's s plan and think I could do it; but is there more of an idiot's guide, also how would I know how to get a full bore-ish valve?

I don't mind using a different manufacturer, I only went to the Honeywell site because someone here toldd me about the nice plans on there, and the 2 port valves are not described in terms of throughput.

mike r

[Andy Hall]

You can get more details if you look on the American web site and also by calling the technical department. IIRC, there are two versions of the 2 port valve base - one with a rotating rubber ball which is similar to the 3port and the other a rotating shoe which moves out of the way completely.

I know that Danfoss also do a shoe type valve.

Have a look at

Parts 339365 and 339370

These people are part of the same group as Plumbcenter but have more heating components.

.andy

To email, substitute .nospam with .gl

[mike ring]

Andy Hall wrote in news: [e-mail]:

Thanks for the link, Andy - just one more question

The throughput on my Danfoss 3 port 22mm is given as

6.8 cubic M at 1 bar.

Do you know any datasheets etc, or even just tell me how this compares to

22mm pipe?

I've tried googling but either get nothing or supertecko stuff

mike r

[Andy Hall]

You're welcome, Mike

The manufacturer's datasheet for a 3port valve should provide a graph of flow vs. pressure head for the valve..

To use this meaningfully, you would have to put it into the context of the entire pipework, boiler and pump design.

There is a calculation method for pipe and pump sizing on the Copper Development Association web site where you can work out pipe resistance and sizing for a given flow. The flow is the starting point because it realtes directly to heat transfer. The issue then becomes one of can the pump deliver sufficient head to meet the total system flow resistance at the required flow rate.

.andy

To email, substitute .nospam with .gl