F n e tank vent pipe dripping

[Inverness]

hi guys,
I recently replaced a gravity cylinder to a pressured cylinder.
In a 3 bedroom council house, Since then the f& e vent pipe is dripping? All I did was drained the central heating and the height for the flow and return was slightly lower than before by 50mm if this could of created more resistance? But I doubt it.
It only happens when you call for Hot water to be heated up?
I don't no if this could be a historical problem and I'm getting blamed now fir it?

The customer drained the heating himself as all I did was swap the cylinder for new pressurised.
There's no magnet filter on the system and it looks 30 years old.
He has adjusted the vent pipe but still same problem. I told him to turn down sped pump. Could the cold feed pipe be blocked? Any suggestions

 

[Burger]

hi guys,
I recently replaced a gravity cylinder to a pressured cylinder.
In a 3 bedroom council house, Since then the f& e vent pipe is dripping? All I did was drained the central heating and the height for the flow and return was slightly lower than before by 50mm if this could of created more resistance? But I doubt it.
It only happens when you call for Hot water to be heated up?
I don't no if this could be a historical problem and I'm getting blamed now fir it?

The customer drained the heating himself as all I did was swap the cylinder for new pressurised.
There's no magnet filter on the system and it looks 30 years old.
He has adjusted the vent pipe but still same problem. I told him to turn down sped pump. Could the cold feed pipe be blocked? Any suggestions

Hello Inverness,

You have replaced a gravity cylinder for a pressurised cylinder but have an f&e pipe? Is this an unvented cylinder or a standard cylinder? What zone valve(s)?

 

[EvilDrPorkChop]

hi guys,
I recently replaced a gravity cylinder to a pressured cylinder.
In a 3 bedroom council house, Since then the f& e vent pipe is dripping? All I did was drained the central heating and the height for the flow and return was slightly lower than before by 50mm if this could of created more resistance? But I doubt it.
It only happens when you call for Hot water to be heated up?
I don't no if this could be a historical problem and I'm getting blamed now fir it?

The customer drained the heating himself as all I did was swap the cylinder for new pressurised.
There's no magnet filter on the system and it looks 30 years old.
He has adjusted the vent pipe but still same problem. I told him to turn down sped pump. Could the cold feed pipe be blocked? Any suggestions

If cold feed pipe was blocked the system wouldn't fill up.

Sounds like it's nearly pumping over, i'd try turning pump down and see what happens. Is the tank low down in the loft?

 

[Inverness]

Heating gravity. Hot water is now been pressurised.
S- plan system.

 

[Inverness]

Apparently it didn't drip before until I replaced the cylinder.
Strange!

 

[EvilDrPorkChop]

Apparently it didn't drip before until I replaced the cylinder.
Strange!

The only difference is that the coil is probably higher in the new cylinder compared to the old one, and maybe a bit more resistance on the flow on the new coil. What size cylinder did you fit?

 

[Inverness]

F& e tank and the vent pipe is seperater to the cold feed it's not a combined f&e pipe.

 

[EvilDrPorkChop]

F& e tank and the vent pipe is seperater to the cold feed it's not a combined f&e pipe.

You asked if cold feed pipe was blocked on your original post, if it was blocked, system wouldn't fill up.

If turning pump down doesn't work, either raise tank or make combined F&E. Have you put a gate valve on return from cylinder for balancing? You could try balancing this down if you have.

 

[Burger]

hi guys,
I recently replaced a gravity cylinder to a pressured cylinder.
In a 3 bedroom council house, Since then the f& e vent pipe is dripping? All I did was drained the central heating and the height for the flow and return was slightly lower than before by 50mm if this could of created more resistance? But I doubt it.
It only happens when you call for Hot water to be heated up?
I don't no if this could be a historical problem and I'm getting blamed now fir it?

The customer drained the heating himself as all I did was swap the cylinder for new pressurised.
There's no magnet filter on the system and it looks 30 years old.
He has adjusted the vent pipe but still same problem. I told him to turn down sped pump. Could the cold feed pipe be blocked? Any suggestions

Has the pump position changed? Or is the pipework slightly different whereby it’s pumping over slightly?

 

[Jones82]

Could just be an old ball valve that needs replacing or the water level is too high in the f&e tank so doesn't have room to expand.

I'd look to the ball valve and water level first, might just be a coincidence

If its pumping over its likely air locked, try running each zone separately and maybe close the bye pass to get the air out of the system

 

[Aire]

Have you checked the water level in the f&e tank? Maybe the float valve is dripping and slightly raising the water level, I frequently find old valves don't fully shut off after a drain down if they haven't been touched in a while.

 

[Aire]

Could just be an old ball valve that needs replacing or the water level is too high in the f&e tank so doesn't have room to expand.

I'd look to the ball valve and water level first, might just be a coincidence

Snap

 

[Burger]

Could just be an old ball valve that needs replacing or the water level is too high in the f&e tank so doesn't have room to expand.

I'd look to the ball valve and water level first, might just be a coincidence

If its pumping over its likely air locked, try running each zone separately and maybe close the bye pass to get the air out of the system

If it’s the ball valve, would this cause the vent pipe to drip?

 

[Aire]

If it’s the ball valve, would this cause the vent pipe to drip?

If it's changed the level of water in the header tank then yes it can.

 

[Inverness]

Everything has stayed the same only thing I did was connected the flow and return to the cylinder coil, thanks guys, I'll try the float valve and see if that makes a difference. If the float valve was letting too much water in the system which would pass through the vent-pipe I never thought this would be possible.

 

[Inverness]

Only seems to happen when the hot water circuit is on. When the heating is on it's fine, I think it's more to do with the balancing the whole system and a replacement float valve.

 

[Aire]

Which side of the vent pipe is the pump.

 

[Inverness]

The problem is everything was fine until the new cylinder was replaced. I didn't touch central heating circulator or zone valves all I did disconnected old flow and return from cylinder and reconnected.

 

[Riley]

Do you know for sure that it was fine before

 

[Inverness]

I'm only taking the owners word for it, he drained the central heating system before I arrived at his house. He said he would fill the system back up himself as he was moving a bathroom radiator which was fine as I connected the immersion. It's weird coz he said didn't drip before but how would you know if it did or didn't? In less the overflow was discharging.

 

[Riley]

And if I had learned anything in this job customers lie

 

[Burger]

I'm only taking the owners word for it, he drained the central heating system before I arrived at his house. He said he would fill the system back up himself as he was moving a bathroom radiator which was fine as I connected the immersion. It's weird coz he said didn't drip before but how would you know if it did or didn't? In less the overflow was discharging.

He’s blaming you, but he drained the system before you arrived - very dodgy territory.

 

[Best]

If it is the vent pipe dripping (pumping over slightly) then I am guessing the new cylinder coil is more restrictive, or there is crud pulled into pipe when system was drained, which would cause a restriction.
Keep any balancing valve on cylinder coil full open to see if that helps.

 

[Inverness]

It was 28mm connected to the coil but I remove about 2oomm of pipe and reduced it 22mm pipe would this be enough resistance for it to pump over?