A couple of queries about an overflow pipe…

[richierich81]

Hi all,

I noticed that the bricks around the overflow pipe that come down from the loft have been going white which shows me they’ve been getting damp.

i think I have found out what’s happening.

I think that when the Bath is running upstairs with both the hot and the cold on the over flow pipe starts to leak. Looking on the internet this indicates a problem with the mixture tap and is to do with the pressure of cold and hot. Is this something a new tap would fix or is it simply just having one tap turned on at a time?

You can see from the photo this has been happening for a while judging by the bricks.

my second question is about the plumbing underneath my cylinder…

see the red valve wheel is that a bypass pipe from the cylinder ? Should the valve be open or closed?m
Thank you

 

[CBW]

It’s usually the sign of a failed float valve, but that’s usually after the hot water has been ran, and it would normally start a while after once the cold water storage cistern has had chance to refill. Leave your bypass alone.

 

[richierich81]

It’s usually the sign of a failed float valve, but that’s usually after the hot water has been ran, and it would normally start a while after once the cold water storage cistern has had chance to refill. Leave your bypass alone.

Thanks Chris. Is there a way I can test it to find out the cause?
The reason I ask about the bypass valve is that I changed the motorised valve and the pump last year and could t remember if the bypass valve was on or off.

 

[CBW]

Does it overflow say 1st thing in the morning before any hot water has been drawn off?

 

[richierich81]

Not that I’ve noticed. It only seems to overflow when the bathroom mixer tap for the bath is running both the hot and the cold feed.

 

[CBW]

That seems a little odd. You could be getting backflow. What you can do is run the bath, and go in the loft and feel the cold water outlet of the cistern, if you feel water being pushed, then I’d suggest you’re getting backflow.

 

[richierich81]

I’ve just tested it again and it’s not doing it now. Just realised that it was doing it when the boiler was running - heating the hot water. Is it bad practice to run the hot water when the boiler is running? Could it be to do with expansion?

 

[CBW]

No it’s not bad practice. You have what’s called pumping over. Might be that the pump is in wrong position/location.

 

[terryplumb]

Do you have two tanks in the loft ?
If so which one is overflowing ?

 

[richierich81]

I’ll need to go up into the loft and have a look. Only moved in last year. I know there is one big black tank up there (plastic). I’ll have a look tomorrow and update the thread. Thanks again for all your help

 

[richierich81]

Right I’ve ventured up to the loft and discovered that there are two tanks up there! A large black tank filled with water and the float seems to be working and another smaller white tank set further back. I couldn’t get across to this without some boards (which I didn’t have!).

I’ve also tried to replicate the overflow by turning on hot water taps and cold in the bath and it’s not triggered.

I’m wondering now is if this is happening when the hot water at the boiler has been turned on for an hour.

Any thoughts? Should I call a plumber out?

 

[terryplumb]

I can't tell for sure ,but the water level in the large tank appears to be far too high. Measuring from the top rim ,how far down is the water level?
Do both white plastic overflow pipes ( one from each tank) join together somewhere ,going into one communal external pipe ?
Do you have a shower pump ?
Can you show us a pic of the bath tap ,and is the cold tap connected to the cold mains ?

 

[CBW]

I can't tell for sure ,but the water level in the large tank appears to be far too high.

That’s what I thought Terry, definitely looks too high, not far from float valve.

Do both white plastic overflow pipes ( one from each tank) join together somewhere ,going into one communal external pipe ?

looks like there’s a tee on one of the photos.

 

[terryplumb]

Yes Chris ,I can see the Tee ,but I can't see the overflow pipe from the F&E ,probably buried under insulation !!
Without sight of the inside of both tanks ,and no seperate pipes to indicate which is overflowing ,it's hard to come to a conclusion,but I suspect the issue is with the cold water storage not the f&e.

 

[Harry Bloomfield]

Any thoughts? Should I call a plumber out?

That photo with the blue float - the level appears to be much too high, bend the brass arm down, so it lowers the shut off level. It also looks fairly new, both the tank and valve, maybe who ever installed it, didn't bother setting it?