One for you commercial guys

[melmos]

View attachment Toilet_pipe_plan.pdf
Public Ladies toilets having a problem with flow of water to washbasins. The taps are infrared with a solenoid, every morning when taps are tried there is only a trickle and its pulsing, after a few minutes they start to splutter and air is ejected and then a good flow of water. If left for half an hour they are back to a dribble. I have cut a panel in the wall and can see that there is a secondary return attached to the main flow pipe before the first tap, there are four taps in total. My thoughts are that the secondary return is pulling the flow of water away from the taps and if it was rerouted to the fourth tap, then this would solve the problem. I await any input from you more experienced lads. I have attached a pdf drawing of the layout.

 

[ShaunCorbs]

What is the hot supplied by and any tmv valve and have you tried turning the hsr off to see if that fixes it ?

 

[melmos]

ShaunCorbs, Thanks for your response. There are 2 calorifiers in the basement, the toilets are situated on the 4th floor. The cold supply comes from a tank on the roof which is next floor up. There are 2 TMV's each supplying 2 taps and if the hsr is the secondary return, then no I haven't turned that off.

 

[melmos]

I would also like to add that before these toilets were refurbished everything was working fine.

 

[ShaunCorbs]

(Hot secondary return) and always had this problem or just started ?

 

[melmos]

Hi ShaunCorbs, the toilets are in a department store, they were refurbished 2 years ago and this has been going on ever since. Previous to this they had RADA infrared taps and never had a problem. It was first thought that the taps set up was causing the problem, but they then moved on from that and they seem to have lost their way with it. I know someone in their maintenance department and they asked me to take a look. So, don't you think that it is the siteing of the Secondary return that is causing the problem?

 

[ShaunCorbs]

Hi ShaunCorbs, the toilets are in a department store, they were refurbished 2 years ago and this has been going on ever since. Previous to this they had RADA infrared taps and never had a problem. It was first thought that the taps set up was causing the problem, but they then moved on from that and they seem to have lost their way with it. I know someone in their maintenance department and they asked me to take a look. So, don't you think that it is the siteing of the Secondary return that is causing the problem?

If there was no problem before they changed the taps and Pipework was not changed taps at fault (maybe) maybe worth trying one closest (first one on the line) but everything looks fine with the Pipework how it's piped etc

 

[stevetheplumber]

sounds like the pump is sucking back when the taps are open switch the seconday pump of and see if that makes a difference to flow i cant remember if there are speed setting on secondary pumps but if there is try lowering the setting

 

[melmos]

If there was no problem before they changed the taps and Pipework was not changed taps at fault (maybe) maybe worth trying one closest (first one on the line) but everything looks fine with the Pipework how it's piped etc

So, with the secondary return at the beginning of the run of pipe, that doesn't make any difference to the pull on the flow to the taps. I am going in tomorrow so I will isolate the secondary from the main flow and see what happens. Thanks for your input.

 

[melmos]

sounds like the pump is sucking back when the taps are open switch the seconday pump of and see if that makes a difference to flow i cant remember if there are speed setting on secondary pumps but if there is try lowering the setting

As above, stevetheplumber, the secondary pump is on a lot of pipe work throughout the building. One thing I have found out is that the hot supply pipe and return feed on the same floor, 2x kitchen sinks, then the ladies toilets,4 washbasins, then a disabled toilet, 1 washbasin,then the gents toilet, 4 washbasins and finally on to a cleaners sink. The kitchen sinks and the cleaners sink on each end of the main run of pipe do not have a problem. All the washbasins in between have the same spluttering problem and these were all part of the refurbishment.

 

[melmos]

Went to store this morning, there was agate valve on secondary return, which I turned off. I got a good flow through the taps, this leads me to believe that the return has been connected into the wrong place on the primary flow pipe. So if I was to re pipe it to the other end would this then cure the pull back from the taps while keeping a flow of hot water there without pulling off too much water, look forward to some feedback.

 

[ShaunCorbs]

Stick a single check valve (to the taps) after the t to the secondary return link

 

[melmos]

Stick a single check valve (to the taps) after the t to the secondary return link

Thanks for that ShaunCorbs, that would be the easiest solution as access is difficult.

 

[ShaunCorbs]

Thanks for that ShaunCorbs, that would be the easiest solution as access is difficult.

Also check the pump speed as you only want enough flow to move the water round slow doesn't need to be fast, or partly close the gate valve if you can't change the speed

 

[ShaunCorbs]

I would be looking how the air was getting into the line as well

 

[melmos]

Just to update, I went in again this morning as I received an email yesterday telling me that the taps were back to spluttering. I managed to get in to the ceiling void above toilets to try and find where the original pipes were coming through. I found them and saw that they had gate valves on them, but they are now behind a tiled wall. On this information I managed to feel the pipes, the flow was hot to the touch, however the return was cold, this now leads me to believe that the gate valve that I found is turned off. I have informed the maintenance team and they are going to cut the tiles out and gain access to the valve. With a bit of luck it could be solved. Thanks for all input given.