It Kettles, but what is this?

[Welshtog]

Hey everyone, first time posting so please be gentle

Ideal classic heat only vented system that started kettling during hot water heating most times and every now and then on radiator heating.

I have:

Fitted an auto vent, thinking it was air as the little screw vent always seemed to have air in it
Replaced a thermocouple on the boiler on some advice (Kind of was kettling at the boiler)
Drained, add cleaner, run for four weeks, drained and added treatment
Drained, isolated each rad, taken off, washed through, re-commissioned system
Installed a magnaclean. It's clean (although I don't think its in the best place)
Replaced the 3port valve as it failed.
I have not replaced the cylinder or the pump

The system is 21years old and as soon as we can start the kitchen extension, I am going to replace the boiler(++) The boiler and the other kitchen appliances must have known we were drawing up plans as in the last month, the washing machine went bang and flooded the floor, the fridge died and defrosted the lot and the boiler started to squeak. Dam even the toaster died! The squeak is the duct fan bearing,, little WD40 and I hope they don't seize up for now.

I am posting today due to the fact that I want to replace the boiler, but of course, do not want to still have the kettling (if it's not the boiler)

I will change the pump out and am debating on switching to a sealed system, but anyhow I am convinced the kettling or at least this is where it kettles from, but I can not find a replacement or for that matter the good name for this (picture below) unit to enable me to google it.

Could it be this that is causing the problem? Why can I not find one to order one?

If you were in my shoes, would you replace the pump and boiler post a power flush or would you consider a different path. For ref, four-bed detached. One bath, onsuite. 10 rads (11 when we do extension)

Thank you all.

 

[Welshtog]

DWBoiler

• Welshtog
• 14 Mar 2021

what is this?

 

[terryplumb]

It's an air separator ,and may be choked up with magnetite.

 

[ianmcd]

Replaced a thermocouple on the boiler on some advice (Kind of was kettling at the boiler)

WOW you should be giving us advice then ! your boiler does not have a thermocouple

 

[JohnD]

Are you in a hot-water area?

 

[terryplumb]

Are you in a hot-water area?

Eh ?? What's a hot water area ?

 

[JohnD]

Hard-water area.

 

[Welshtog]

WOW you should be giving us advice then ! your boiler does not have a thermocouple

Pedent Yeah, I meant thermostat

 

[Welshtog]

Hard-water area.

Yep Hard indeed.

 

[JohnD]

so it may have a crust of limescale inside. like an old kettle. lime combines with magnetite to form a very hard material.

X200 may help. Yours sounds bad, so maybe two bottles.

You do not drain it out.

 

[Welshtog]

It's an air separator ,and may be choked up with magnetite.

Thanks Terry, that makes sense, What I don't have then is the head top-up feed, only the vent. Would you say that is an incorrect or poor design choice?

Would make sense is the kettling is concentrated here then.

 

[Welshtog]

Looking at this pic of what looks to be the same (why did the prior owner paint everything silver), would make out for my pump to be connected to the vent and the cold feed used as output with output capped off.

 

[Welshtog]

Now I know its called an Aerjec, Google has provided me with hours of rabbit holes.. seems the consensus is they trap more sludge than air, bin it!

Thank you all. most helpfull