Gunged up or what after some 30 plus years

[Bogart]

Would agree with you that the CH pipework obviously passes considerable more water that the HW pipework.

I have a Fernox TF1 which seems to be continually catching magnetite. The thing does heat up fine but lots of crap present that really should not be there. Oh and the boiler is an old oil Boulter Camray. What I found after taking the current separator out, what a job that was, was that the
gunge only starts at the elbow leading into the separator. The pipework from the boiler up till the elbow is fine by comparison. Now another couple of questions regarding this setup. Between the separator and the AB entry on the 3 port there is currently, or was until I took the pipework out, obviously the pump but also an automatic air vent. The length of pipework between the separator and the autovent is no more than say 500mm, is this superflous as the separator is so near and I would think will get rid of air better than any autovent. And finally would it be worth installing another TF1, would be just after the pump, the one currently in situ is in the boiler house on the return just before entering the boiler. I have a coupe of TF1s so would not need to buy anything?

As am going to do the 28mm pipework tomorrow any thoughts on if I should add the additional airvent only some 500 from the air separator. Basically 300mm of pipework and the pump separating them.

 

[Ric2013]

I don't really like the idea of having an automatic air vent on the suction side of the pump, though should be okay if there is sufficient static head.

 

[Bogart]

The vent would not be on the suction side of the pump, sorry if I did not make that clear. To clarify the pump sits on the outlet of the separator and then after the pump is about 300mm of pipework before the air vent. There then follows about 200mm of pipework before port AB on the 3 port valve.
I am wondering if it is worth having a vent, auto or manual, so close to the separator. There is a manual vent on the return pipework before it heads off back to the boiler.