Central heating vent pipe - continual flow of hot water

[Oxygene]

I have had a condensation problem in my loft, which started within a week or so of me replacing my central heating water pump. I have just been in the loft and noted that as soon as the central heating system fires up, water flows out of the vent pipe and into the F & E tank.

I assume this is not normal, so what could be causing the system to do this? How can I resolve this problem, as I suspect that this is the cause of my condensation problem.

Any help would be greatly appreciated. Many thanks

 

[keego]

Reduce the pump speed to 1, it's probably on 3. If the CH is OK on that speed leave it at that if not put it up to 2.
You did put the new pump on pumping the same way as the old one?

 

[plumbplumb]

possibly a blocked/restricted cold feed

 

[leopardml2341]

Do the rads get hot ?

Fluids like electricity will always take the path of least resistance, so it seems like the pump flow is over pumping or there's a blockage somewhere (or a valve closed).

Is the (new) pump speed the same as the old one ?

Does altering the speed stop the vent pipe flow ?

If you can post this info it might help with a diagnosis

Rgds,

Andy

 

[Nige F]

With the water running like it is - you`re oxygeneating it - leading to corrosion

 

[Oxygene]

Thanks for all your replies so far. I replaced my Grundfos 15/60 with a WILO Smart A type.

I am beginning to suspect that I my have installed the pump the wrong way round! I assumed that the arrow on the pump indicated the direction of the flow of water through the pump, was I correct? Therefore, I fitted the pump with the arrow pointing away from the F & E tank and towards the HW/CH valve?

I currently have the pump on the lowest setting, but water is still flowing out of the vent pipe!

In answer to Andy's questions: Yes, the rads get hot. No, changing the pump speed does not change the flow rate of the water coming out of the vent pipe.

Thanks again for all your help so far

 

[plumbplumb]

a picture of your pump cold feed vent pipework may be helpful to make sure it is piped up correctly

 

[Oxygene]

Photo of installed pump - In this image the 'arrow' is pointing View media item 55234 [/img]

Just to confirm that the pipe attached to the top of the pump is from the F & E Tank.

In answer to Andy's questions: Yes, the rads get hot. No, changing the pump speed does not change the flow rate of the water coming out of the vent pipe.

 

[plumbplumb]

could be restricted around that air separator.
You could try running a magnet over it see if it attracts itself to the pipework

 

[Oxygene]

I have just used a fridge magnet (sorry, only one I had to hand) and it does attract itself to the air separator.

The magnet is not strong enough to hold itself there, but you can feel the magnetic force pull it in towards the AS when you hold quite near.

Is there an easy way to sort this out, or will I have to get a plumber in to change it?

 

[Oxygene]

I am assuming that if I increase the height of the vent pipe so that it is above the height of the head of water, then I could get it to stop. Whilst I do not have any height left to extend the pipe, would it be possible to attach a length of hose and run it further up into the loft space, and then loop it back down into the F & E tank?

I wasn't proposing this as a permanent solution, but just as something I could use for a couple of days.

 

[plumbplumb]

would it be possible to attach a length of hose and run it further up into the loft space, and then loop it back down into the F & E tank?

not really but it's your house, besides it will be likely it has been doing it for a while so a couple more days or so isn't going to make much difference.

extending the vent pipe is papering over the cracks. the magnet test is not definitive but it indicates the air sep and surrounding pipework are possibly restricted.
It would need part draining and a section cutting out to investigate whats going on.
If your not confident to do it i would suggest getting in someone who is.

 

[Oxygene]

Thanks to all for your responses, they have been a great help.

Just to update you, I called in a plumber yesterday who diagnosed a blocked air sep. He is coming back in a few days to replace it.

I will post again when the job has been completed, to let if you know if this did indeed fix the problem. Having looked at the system and read your threads here, I am confident that it will.

Thank again