Horizontal? Flow-sensor sought....

[Ookysoft]

I'm looking for a flow sensor switch to operate when water flows.

I'm kinda thinking a combi boiler spare part will do the job, only which boiler's spare?

Ideally.... fitting 22mm, horizontal operation or downflow [sprung?], 240v on/off as opposed to flow rate feeding a circuit board...

The application is to start an extractor fan when water is supplied to a shower.

 

[pannierstan]

Sounds like you could do with the old Red flag type paddle switch which came on the old Hot water express and Ideal Sprint, but all the latest type ones were vertical reed switches with magnetic plunger.

Could you not use a pressure sensor from Machine Mart or such which comes on when pressure drops?

Stan

 

[GasAid]

All I can think of at the moment is something like the Vaillant AquaSensor; but the connections on that aren't really suitable for anything except fitting inside a Vaillant

Will have a think though.

 

[Ookysoft]

I don't think I can use a pressure sensor as, in a gravity fed system, the pressure will be standard I guess? Though it will fluctuate when water is drawn, I don't think it will be enough! I think I need a sprung magentic plunger & reed switch construction........

 

[Strachan]

I remember Danfoss doing a paddle type. Can`t remember the voltage. I think the smallest they did at the time we fitted them was 1" bsp. They screwed into a "T" in the flow line.

 

[ChrisR]

There are many flow sensors from general electronics equipment sort of companies like rswww, Farnell, and others. And every shower pump has one... What flow rate do you want it to switch at?
Here's a few...

Or get a shower pump (you know you want one) and connect the fan to that
Or use a humidistat (reliably come on when it rains if exposed to outside air)

 

[Agile]

Yes, Chris but all those are 15 mm!

The Vaillant aquasensor is no use as that only gives and AC output from the Hall effect detector.

The only one I can think of is the 22 mm system flow sensor used in the Potty Lynx. Even that often gave trouble when it got a bit shudged up!

To the OP are you sure you cannot use a thermal switch instead? That greatly widens the scope and is cheaper!

An alternative is a pressure differential valve connected across a gate valve set as a variable flow resistance.

I think I have seen Chris's pictured Honeywell one inside a dreaded Glow-worm boiler!

Tony

 

[oilman]

Grant UK do a paddle type for 22mm which is used on the larger Vortex combi.

 

[TicklyT]

There's a couple of RS ones that might do the job....

eg 257 082 or 256 578

 

[bripl]

have a look at the mts stratos 31kw combi i think that has a 22mm flow switch

 

[ChrisR]

Yes, Chris but all those are 15 mm!

Not exactly. The one bottom left can be used with pipes up to 8 inch, the one to its right is 22mm, etc.

 

[Rob]

WB 24i. Simple paddle type, 22mm from memory.

 

[bripl]

rob wrote


WB 24i. Simple paddle type, 22mm from memory

i think he wants something a bit more reliable changed four of them this week

 

[Softus]

The Vaillant aquasensor is no use as that only gives and AC output from the Hall effect detector.

Vaillant ® ?

The only one I can think of is the 22 mm system flow sensor used in the Potty Lynx. Even that often gave trouble when it got a bit shudged up!

Potty ® ?

I think I have seen Chris's pictured Honeywell one inside a dreaded Glow-worm boiler!

Honeywell ® ?
Glow-worm ® ?

 

[pannierstan]

WB 24i. Simple paddle type, 22mm from memory.

Its 15mm on 1/2"bsp threads me thinks