F and E tank hot, radiators cold

[Polaralias]

So we have a conventional boiler and CH system and recently (last week or so) I've noticed it getting worse at heating the downstairs radiators.

For a bit of potentially useful background - In November I added a rad in our basement and balanced the system after that things were working mostly OK with them heating up nearly at the same time. The dining room and basement weren't really heating up that much but we don't use those rooms so it wasn't an issue.

We have 4 rads upstairs and 4 downstairs (plus one in the basement) and now the 4 downstairs don't get hot at all. I'd also noticed the F and E in the loft now gets hot nearly immediately.

To try and fix it I have:
Replaced the motorized 3 way valve head (it seemed like it wasn't working before)
Added X800 cleaner and then drained the system completely and filled it up adding in X100
Turned the pump (Groundfos UPS2 15 - 50/60) from 3 down to 2

I filled it a couple hours ago and the upstairs ones are still not fully hot but the F and E tank is too hot to put your hand in. If I put on the HW it gets hot fine but the CH seems to now be taking ages to heat up in the radiators that used to get nice and hot with the downstairs ones still not heating up. There was a loud water gurgling sound before draining today but since then it seems to have stopped. Afaik there isn't any air in any of the rads or in the pump as I've bled them all.

Any ideas on what I can try next?! Moneys a bit tight so plumber is definitely a last resort.

 

[ianmcd]

turn the hw off and the heating on, close all the rads and open one at a time untill it heats up then cose that and do the same with the next one and so on

 

[Polaralias]

turn the hw off and the heating on, close all the rads and open one at a time untill it heats up then cose that and do the same with the next one and so on

Close all rads on both return and TRV, leave one TRV side open but return closed then once hot close TRV and move to next?

 

[ianmcd]

no just close the TRVs dont touch the lockshield ends

 

[Polaralias]

no just close the TRVs dont touch the lockshield ends

Well the first one I'm trying it on is getting a lot hotter which is amazing. Shall update once I've done them all, could this sort the hot water in the f and e tank issue?

 

[ianmcd]

if it is air and you manage to force it out then yes it will