Flow through header tank

[G6XXL]

I have flow through header tank this is causing condensation in my loft as its quite hot water flowing. Its not just expansion but a constant flow, as much as a hose-pipe with the pump speed to max.
I have tried adjusting flow of pump down When I block the feed from the tank to the system with my finger the flow stops.
if I block the vent which has a slight pressure obviosly the flow stops, my vent 22mm and feed 15mm come from the middle of the system pipework on the common flow and return before the 3 way valve is this the problem, and they need to be re-routed to the boiler.
Thanks in advance.
Greg

 

[Softus]

I don't understand your description of the pipework.

In the direction of flow the order should be:

1. Vent.
2. Feed.
3. Circulating pump.

Is it like this? If not, what do you have?

 

[G6XXL]

Yes they are in that order but the pump is at the boiler the vent and feed are in horizontal section of pipework about 10m from the boiler.
Greg

 

[Softus]

You've lost me - is the pump between the vent and the feed?

 

[G6XXL]

No the pump is at the boiler return the vent and feed are between the boiler and cylinder which is about 15m along a horizontal section . The vent is connected to the flow pipe and the feed is connected to the return pipe around half way along this horizontal section.
Greg

 

[Softus]

OK. It's time to get the full information on your system.

Please read this and provide as much as you can.

 

[Bambergaspipe]

It`s not uncommon for the pump to be situated on the return side to the boiler, sounds like your system has been in for a while, how long has this been going on for? Do you have constant hot water pumping in to your header tank via the vent pipe?

 

[Softus]

Trouble reading? This might help.

 

[Bambergaspipe]

Go away Muppet.

 

[Softus]

No, seriously - it would work wonders. You'd learn all about grammar, expand your vocabulary, and understand when and when not to use capital letters!

I know it seems utterly impossible to you right now, but, given time, you'd understand statements like the following:

if I block the vent which has a slight pressure obviosly the flow stops

 

[Bambergaspipe]

quote="Softus"]No, seriously - it would work wonders. You'd learn all about grammar, expand your vocabulary, and understand when and when not to use capital letters!

I know it seems utterly impossible to you right now, but, given time, you'd understand statements like the following:

if I block the vent which has a slight pressure obviosly the flow stops

Goodnight Softus. I`m bored.

 

[G6XXL]

Yes constant flow. We used to have a coal range in the kitchen, i removed it and extended the pipes to the garage and fitted an oil fired boiler + controls as it was gravity hot water, now pumped with a motorised mid position valve.
Greg

 

[Softus]

Did you add an inhibitor to the primary circuit? How long since the last maintenance was done on it? Do you ever have to vent air from the rads or anywhere else? If so, what colour water comes out? And what colour is the water in the F&E?

 

[G6XXL]

Just flushed it out come out like oxtail soup, only recently moved in so not sure of history got some inhibitor to put in. Water in f&e tank was like oxtail as well.
greg

 

[Softus]

You said that you replaced the boiler, so how can you be unsure of the history?

Adding inhibitor now won't achieve anything. As a bare minimum you need to flush out the system with clean water. A chemical clean would be preferable, and a powerflush might be necessary, but the latter can expose latent leaks.