How to replace siphon in Doc M cistern

[Hilary Horse]

Hi,
I'm trying to replace the siphon in a Doc M toilet cistern. The supplier told me that I should simply be able to unscrew the old one and replace with the new.
However, the overflow pipe forms part of the siphon so I cannot unscrew from inside the cistern as it hits the side and can't turn any further than 3/4 of a turn.
Does this mean that I need to remove the whole cistern to replace the siphon?
P.S. I'm female with limited plumbing experience so any advice would be handy. I'm determined to do this myself !!
Thanks, Hilary x

 

[joni os]

Doc M refers to special needs category of Building Regs. and is insufficient to identify make of syphon. Normally you would have to part cistern from pan. Turn off water, unscrew from wall, loosen bolts etc. to change syphon. Most syphon can now be serviced without this hassle, so unless broken beyond repair, service may be best option.

 

[rpm]

Welcome along Hilary, a photo or 2 might help here if you can. And what is the fault?

 

[Hilary Horse]

I've been struggling to attach a photo using my phone.
The toilet flushes but doesn't refill the cistern. The water goes down the drain.

 

[joni os]

Might be bayonet fitting, half turn and lift. Are you replacing like with like.

 

[rpm]

Anybody else think possibly the float valve is stuck and water going through the internal overflow?

 

[Hilary Horse]

The new siphon was supplied under warranty from the manufacturer so should be like for like. Unfortunately, it's a screw fitting. It's sounds as though I'll need to remove the cistern but how do I detach it if the siphon is holding it to the pan etc?

 

[Hilary Horse]

If I press the top of the siphon, it makes a slight thud noise and then the cistern fills with water. This is how I've been flushing it 😉

 

[rpm]

Looking at your photo the siphon valve is to the left with the fill valve to the right, which one are you pressing?

 

[stevetheplumber]

the syphon they have sent you will come apart about two inches above the threaded part try it on the new one first grip either end push together and twist anticlockwise once you can see how it splits you will realise how to replace

 

[Hilary Horse]

I'm pressing the siphon

 

[Hilary Horse]

Thanks. I'll take a look when I get home 🙂

 

[stevetheplumber]

there are three things allow the water to flow down into the pan
1 fill valve not closing in this case you will see the water going higher than the overflow
2 flush valve passing this is the part you have and can be done without removing the cysten
3 the cradle of the flush valve is either not tight in the pan or has cracked if its this the cysten has to come of

 

[rpm]

I'm pressing the siphon

Wasn`t being condescending or rude just that some people can get the two mixed up.

 

[Hilary Horse]

It's ok . I did say that I was female in my first post, so completely understandable!! 🙂 🙂

 

[Hilary Horse]

I've managed to take the new one apart (though it didn't like being twisted and I nearly broke it !)
I can't budge the old one in the cistern though. I'll keep fiddling carefully for a while, but I don't want to break everything 🙂

 

[Phil]

I think maybe the cable has seized and after flushing the washer isn't going back down to seat.

Give that old one a damn good twist anti clockwise while holing the base plate.

 

[Phil]

Or is it clockwise?...the pic looks clockwise...

 

[Hilary Horse]

It's clockwise to undo it. It's very stiff and won't turn. If I force it, it'll break. I can hear the plastic creaking in a threatening manner. I'll try again later - with caution 🙂

 

[Phil]

Nothing to worry about, if the water is off nothing bad can happen, the old one is rubbish anyway...you can do it..

 

[Hilary Horse]

I'm not worried about breaking the top part. I don't want to break the bottom part or it'll definitely be a case of taking the whole cistern off !! 🙂

 

[rpm]

It`s those plastic interlocking lugs that break on the part left in the cistern, then as you say you have to remove the cistern to replace the whole lot so once the lugs disconnect rock the top half to and fro a little bit and don`t forget to clean the plastic face where the rubber sits, any debris left there and it will no doubt leak.

 

[dean.diy]

@Hilary Horse, how did you get on? Admire your perseverance.

 

[Hilary Horse]

I've had to stop for a while. I need the water turned on. Will have another try tomorrow 🙂

 

[PriestyUK]

It should just with a quarter turn click out and the same method to put back in. Make sure you spray some descaler and get rid of any scale build up on the base bit that will still be attached inside the cistern this way the rubber will seat back down nicely and not allow water to pass through.

Your plumbing stage 1 toilet spares certificate is in the post 😀