Making an internal overflow on a cheapie syphon.

[cr0ft]

Hi all.

I don't know if this will help anyone but it helped me the other day. Had a new WC supplied with a syphon valve without an internal overflow. Never had that happen before so I guess it's not a common problem. Not keeping overflow pipe and fittings on the van I made a simple modification to the valve to make an internal overflow. Also meant I have finally found a use for the same roll of 10mm microbore I have had in my van for years!

Drill a 10mm hole in the top of the syphon valve. This is just the right width to fit a nice straight piece of 10mm microbore down (funny that). You want to cut it about 1/4" higher than the height from the bottom of the inside of the cistern to the top of the syphon valve.

A little bit of silicon sealant around the joint between the syphon valve and the microbore and job is a good one.

No more need for unsightly overflow pipework. That's one less thing to stock in my van!

 

[Howsie]

Good idea. Is 10mm wide enough to cope with the water?

 

[SimonG]

Aye it would depend on the flow rate of the incoming water. 10mm may struggle if the inlet valve lets go at full tilt. Did you test it at full rate?

 

[WHPES]

By the time you've messed about you might as well go to the merchants and purchase a siphon with integral overflow.

 

[thereisawizza]

I saw a device you could retrofit to a siphon; you drill a 10mm hole in it and a sprung clamp fits over the hole with a float attached. When water level rises, float pings the spring!

 

[cr0ft]

By the time you've messed about you might as well go to the merchants and purchase a siphon with integral overflow.

Haha. Took 2 minutes tops to do. I was doing a job away from my normal area and had to improvise as it would have taken me ages to find a merchant who wouldn't rip me off. You know how they are in these circumstances!!

The way I looked at it is most of the syphons like the Dudley Turboflush have a very small hole for the overflow. I guess this is because when fill valves start to go it tends to be drip by drip doesn't it?

You could put in any size pipe you wanted of course, 10mm was just what I used. 15mm would work fine to be honest as well. As long as the pipe goes down to the bottom of the cistern level it doesn't interfere with the syphon action at all.