Header Tank Temperature

[Stratf01]

Just been in loft and noticed header tank on my vented system is hot. I understand that this acts as a feed for heating and expansion when heating water gets hot.
Is this normal for tank to get very warm?

Both the feed pipe and vent pipe are hot but no water coming out of vent.

Never noticed before and had no work done recently although I have a suspected 2 port valve issue as hot tap water always very hot despite no hot water is active. Also waiting on getting a system flush as have hydrogen in rads.

Heating after bleeding works well.

Any thoughts or suggestions hugely appreciated

Thanks

 

[SJB060685]

I ment the pump over could happen if either CH or HW were on on their own and demand stopped, if the restriction is where we believe it to be.

 

[John.g]

If you're combining it there should be no valves in any vent pipe for obvious safety reasons. Come out of bottom of header tank in 22mm and tee into the vent, the vent then continues to rise up and over the header tank, with 450mm minimum between water cold fill line and top of vent u bend. You can then blank off where the old fill entered the system.
There are other options though as I said above but the primary job is getting the system cleaned.

I would be inclined to do the combined job before system clean (obviously flush out the F&E tank through the cold feed isol valve at the tank when disconnected) as an oil fired boiler Hx is just basically a steel box of water which won't easily get choked, the system can then be cleaned/flushed out at ones convenience especially if the pump over/air ingress problem is now solved.

 

[SJB060685]

The thing is mate and im not saying the system is this bad but I once attended a job, oil fired external with vent teed in after the pump. It was constantly pumping over whilst in operation (not the case here, so obviously less air ingress) but the system was so bad that every inch of the system was riddled with sludge, throughout most of the 22mm system it had an internal bore of 2 or 3mm max and im not exaggerating. The boiler was just as fouled.
Where as I agree combining the two might fix the pumping over I really don't think flushing the system should be ignored. The quality of water, its cleanliness and the amount of oxygen all affect its conductivity, its PH value etc etc, all of this can add to serious corrosion if not addressed.
Have a read up on VDI 2035 water treatment. Its a technical standard in Germany, not over here yet but explains what I said above and really should be used of here.

 

[Stratf01]

Thanks again.
Just to be clear I realise more is involved than simply combining to he vent and feed and will apply the other points. Just needed to get this side of things clear in my head.
I noticed there is another plastic kinked 15mm pipe done away with behind emersion to perhaps this is why they fitted a gate valve at pump for everything the pipe clogs up maybe 🙄

I've made another sketch as to what I think you are telling me 😃

Probably got it wrong again and apologise if so.
I'm keen to learn at least 😊

 

[John.g]

That's it, no isol valves on the vent but you may leave the isol valve on the cold feed , if a gate type, (with wheel) as there is practically no resistance in this when fully open. You can also leave the isol valve where the cold feed was/is teed in to the vent and just close it, can always remove it when carrying out system clean later.
Is the vent actually passing up adjacent to the cold feed at the header tank, as shown?, if so a very easy task to tee in.

 

[Stratf01]

That's it, no isol valves on the vent but you may leave the isol valve on the cold feed , if a gate type, (with wheel) as there is practically no resistance in this when fully open. You can also leave the isol valve where the cold feed was/is teed in to the vent and just close it, can always remove it when carrying out system clean later.
Is the vent actually passing up adjacent to the cold feed at the header tank, as shown?, if so a very easy task to tee in.

Great thanks John
Yes the vent is running right next to cold feed at tank so will be very straight forward.

Ta

 

[Stratf01]

Just wanted you thank you all for the assistance given.
I flushed out the system after combining the feed and vent in the manner suggested. I decided to use a 28mm gate valve below tank reduced to 22mm so as to minimise any restrictions for vent when open.

The header tank was so badly fouled I ended up removing it to give it a thorough clean outdoors.

I also added a magnacleanse filter on the return to hopefully minimise such a build up again along with inhibitor.

The end resulted speak for themselves. Pipe to tank is warm until about a meter below tank where it is stone cold.

No venting when pump stops anymore.

Really happy with the outcome and not possible without the expertise given here.

Thanks a million 😊