Dirty expansion tank

[Willknapo]

Hello folks
My expansion tank in the loft has got a lot of sludge type substance in it why is this?
And also should the water in the tank be hot?

 

[ShaunCorbs]

if its alot no and does it have a lid

no the water shouldn't be hot

 

[townfanjon]

Hello folks
My expansion tank in the loft has got a lot of sludge type substance in it why is this?
And also should the water in the tank be hot?

Maybe 'aired' though

 

[Best]

It ideally should be fairly clean inside the expansion tank, but some slight scum floating or lying sediment is often in them.
Your tank should definitely not be warm and this could be a result of water pumping up the vent pipe - which is a disaster to entire heating systems as introduces oxygen and will destroy rads, fittings and boiler in a year or so. The water being warm can also be due to incorrect feed pipework, but either way you need to get a heating engineer to find out what is causing it.
Dirt in the tank water can be a result of corrosion

 

[Willknapo]

Just had another look and the water is definitely warm but there is no water entering the tank from the vent pipe?

 

[Willknapo]

Just had another look and the water is warm but nothing coming out of the vent pipe

 

[ShaunCorbs]

back filling via the feed pipe it sounds like

 

[Willknapo]

Could this be caused by a blockage?

 

[thompsonbrown]

Ive never found a clean F&E tank but there are limits to how much muck it should contain.
If your F&E tank is getting warm its probably due to the way your system was installed. A lot of installations are done where the combine the feed & overflow pipework or install the feed from the tank after the pump. Both these methods can allow your tank to get warm. If you are concerned get a decent installer out to check your system.

 

[Willknapo]

The system is from the 70s so you may be right. I think I will try and run some cleaner through the system and clean out the F&E tank