Question on Testing Toilet Cistern Overflows

[bruno327498]

Hi,

My elderly cousin lives in a Housing Assn shelterd GF Flat.

In August last year the toilet cistern float valve partially failed but the external overflow was able to deal with the water overflow. The cistern is fed direct from the mains. There is no service valve on the feed pipe.The faulty float valve was replaced with a new float and valve.
In late December the new float valve failed completely and because of the amount of water coming into the cistern the external overflow was unable to cope and the bathroom floor and hall carpets were flooded. In addition the main water stop tap is down at floor level in the corner of a cupboard ,it looks like the original from when the flats were built 38 years ago and was corroded and my 90 year cousin was unable to turn it off.

(Following this second failure the Housing Assn have now-somewhat reluctantly- changed the siphon to one with an internal overflow)

My qestion is this :is it recognised good plumbing practice that when a new cistern float valve is fitted following a failure that a test would be made-by keeping the float valve open manually -to check that any failure will not result in the water overflowing the top of the cistern?

Any replies from plumbers would be much appreciated.
Thanks.

 

[lame plumber]

normal overflows are 21.5mm diam and have been for years, normally ball valves dont fail on full flow and the overflow is in fact termed a "warning Pipe" it is there to indicate an issue that needs an immediate response, problem being that the warning pipes are often in poor places and dont get seen.

 

[bruno327498]

Thanks for that. First time I've heard of a warning pipe.I learn something new every day. If I recall correctly the warning pipe will be the old 3/4" but the mains pressure is very strong. My own suspicion is that the new float had not been adjusted centrally and had caught on the side of the cistern but I can't back that up. But if only on the first repair the overflow/warning pipe failsafe had been tested it would have avoided all the flooding.
Thanks again.

 

[plumben]

as above warning pipes are often mistaken as an overflow, to be an overflow the storage of water has to be over a certain size there fore you wouldn't check overflow capacities

 

[kris]

Very seldom I come accross overflows nowadays as newer models tend to have internal overflows where there's no risk of mess , or if worried about a failed float valve then new washer and new syphon with internal overflow . Also top access for replacing the syphon washer .

 

[AWheating]

an internal overflow is unlikely to cope with full flow rates if its an old fashioned syphon, its there to warn you of a problem. same job as the old external warning pipe would have done.

sounds like the replacement valve was poor quality. If the stop tap is hard to use or access maybe the HA would fit you a sure stop?

 

[bruno327498]

Thanks for that and the ref. to Sure Stop, first time I have heard about that. However six weeks after the flood and after a visit from one of the HA repairman the Stop Tap can still only be turned using grips. They will not even fit a new stop tap further up the pipe so that it would be at shoulder height for my 90 year old cousin to be able to access easily. No way are Progress Housing -Leyland -going to fork out for a Sure Stop.-and this is in so called sheltered housing! Can't call in an outside plumber who would soon get it sorted as they have their own repairmen.
Thanks again.

 

[bruno327498]

Thanks. The HA have changed the siphon for one with its own overflow. However if you hold the float down as though the valve had failed ,the siphon internal overflow cannot cope with the amount of incoming water and if there was not still the external overflow then the water would overflow the top of the cistern. So in new installations where there is no external overflow /warning pipe is some sort of limiter put in the incoming water pipe so that the sole internal overflow is able to cope?
Thanks.

 

[Plumbstar Tom]

I would keep on at the housing association regarding this, and the stop tap needs to be fuunctional. Also you may need a pressure reducing valve as it could be the high mains water pressure that is doing a lot of the damage

 

[bruno327498]

Thanks. I did after some insistence meet on site with one of their Repair Inspectors three weeks ago. Grudgingly he agreed to change the siphon to a siphon with its own overflow and only to "ease " the existing floor level stop tap-which is now tighter than before. I am now 200 miles away. I am starting to think that these are general repairmen and not trained plumbers. In my naivety I assumed that in somewhere like sheltered housing an annual check would be carried out to ensure that the mains water stop tap was in good working order-similar to a Gas check. If it had been my cousin would have been able to turn the water off and the flooding would have been minimal. As it is the HA are making her pay to replace the carpets. (With her contents insurance she is liable to pay the first £250 of the claim because the damage is caused by a water leak)
Emailing the HA is like emailing a blank wall -response is "a repair has already been carried out ....
Amazing.
Thanks again.

 

[bruno327498]

Thanks.In fact when I met their repairs inspector I did mention about a pressure reducing valve but was told this would not be necessary because a siphon with an internal overfow would be fitted and in fact the external warning pipe would no longer be needed but they would leave it in situ!! In practice if the valve fails completely the warning pipe will certainly be needed. But hey what do I know, I'm not a Repair Inspector.
I suppose it all comes down to the HA spending money-not
Thanks again..

 

[bruno327498]

Hi,
I have read all the replies but as a layman I am still unclear as to the purpose of the warning pipe or what I always called the overflow pipe. I had always assumed and there must be many, many people who assume the same that the warning pipe was a safety device that whatever happened to the valve that the water would be taken safely away and prevent any water pouring onto the floor. If it is only a warning device what use is that if say someone flushes the toilet then dashes out of the house ,the valve fails and water pours onto the floor until they return because the amount of water coming in is more than the warning pipe can dispose of ? That is why I am surprised as a layman that when a valve is replaced that a valve fail test for want of a better word is not carried out.

 

[AWheating]

Warning pipe is just to bring a fault to the attention of the user. They are supposed to be in a position that they are noticed very easily.

a flow restrictors in the supply to the float valve would help try and match the warning/ overflow capacity but I don't think your going to get that from the HA if they won't even sort the stop tap out.

Maybe a leak happens in the kitchen wreaking the kitchen because the stop tap could not be turned off, who knows All sorts of things happen and prove a point.