CH Pumping Over into F&E Tank

[self builder 123]

Hi

I have an open vented CH system. I am pretty sure there are blockages that need to be re-moved.

We have removed the cold feed pipe and cleared it. The radiators upstairs started to heat up much better.

Once all the blockages are out I am going to treat the system with Fernox Protector circulated at temperature for 7 days.

I have noticed that the F&E tank is now heating up and some water is spitting out of the vent pipe.

It is my understanding that the remaining blockages may well be causing the water to spit out of the vent pipe.

If this goes unchecked will the F&E tank fill up and then run out of the overflow ?

Many thanks.

 

[Agile]

More problematic will be that pin hole leaks will start appearing ion your radiators!

It really needs sorting out quickly! Thats before Hogmanay!

Tony

 

[self builder 123]

Hi

Are you saying that the pin holes will appear when I try to clear the sludge from the system with the chemical cleaner ?

 

[self builder 123]

Sorry will the F&E Tank overflow ?

 

[Agile]

Unlikely! But in any case it should have an appropriate warning pipe ( overflow).

But over flowing is not a serious problem!

Holes in your rads will be!

Tony

 

[self builder 123]

Hi

Under normal operating conditions should the water in the F&E tank be hot or is it the over pumping which is causing the water to become hot ?

 

[JohnD]

what you are describing is quite common when there are partial sediment blockages in the system interfering with correct flow

you did not mention cleaning then out. Adding an inhibitor will not remove the existing sediment

put in a litre of Sentinel X400 which is a very mild, non-acidic cleaner that will loosen the sediment blockages and allow the circulating water to wash them away. You leave it for four weeks with the system running as normal before draining, rinsing and refilling. You will know it is starting to work when the circulating water goes jet black with loosened sediment.

The pumping over you describe will add dissolved air to the water, and this will cause the radiators to rust away from the inside, causing the holes mentioned.

For today, turn the pump speed down and see if this reduces the pumping over.

There are faster-acting cleaners you can use if you are in a hurry and have time to drain, fill, rinse etc in the next day or so.

The water in the F&E should normally be fairly cold as there is no flow into it. A small amount of heat can be conducted up the F&E pipe (but no the Vent pipe) if it is short, vertical and well-insulated

 

[dcawkwell]

Remove the header tank and install a sealed system kit.
The flush the whole system through with cold mains.

Header tanks have no place in a modern central heating system.

 

[self builder 123]

Hi

Many thanks for the information regarding pumping over into the F&E tank.

I have a bottle of Fernox Restorer F3 to add to the system which I plan to circulate round at low temperature for a week before draining.

I plan to drain the system down completely before adding the Restorer. You mentioned that the water will become black when the Restorer has done its job.

When I drain the system before adding the Restorer what colour is the water likely to be - I am assuming it will be brown as there is a brown sludge in the bottom of the F&E tank ?

Look forward to hearing from you.

 

[JohnD]

Bale all the mud out of the F&E tank and sponge it clean before you start.

No sense in letting it add to the existing sludge.

I haven't used Fernox F3 but no doubt it is good stuff if you follow the makers directions carefully. Note especially para.s 3 and 4 in "Application and dosage"
http://www.fernox.com/files/Fernox/Content/PDF/English/F3 Cleaner 500ml with CB logo.pdf