Water venting into header tank

[Graham_84]

Hi Guys

I’m no expert so excuse the question if I’ve done something wrong.

I noticed some persistent noises happening with my heating. I therefore decided to use the 3 stage fernox fluids. F3 then F1 then F2. This meant that I had to completely drain system and refill a couple of times. I understand I’ve got some weird inverted system as it took ages to drain the system and I only have a small header thank integrated and above the tank. (Nothing in loft and hot water is mains fed by with mixer)

Since draining and refilling system I have water periodically venting into the header thank and the pump stops at same time and restarts. I have captured a video at the exact moment this happens (attached with pics). I have bled all rads and the pump itself and all Rads are hot.

Is there anywhere else I’ve missed needing bleeding. Is that vertical pipe from the motorised valve anything needing opening (what is it)? Is there anything else that could be causing this venting?

 

[John.g]

Can't play the video, the "small" tank that you are talking about is I think part of the HW cylinder (cold water supply) and should have nothing to do with the venting problem, or maybe there is another smaller open tank above the HW CWST (green) tank, if so post a photo of this and any pipework.

 

[Aquarius]

Can't play the video, the "small" tank that you are talking about is I think part of the HW cylinder (cold water supply) and should have nothing to do with the venting problem, or maybe there is another smaller open tank above the HW CWST (green) tank, if so post a photo of this and any pipework.

It’s a combined cold water tank/hot water cylinder and seems to be coming from what appears to be an expansion hole? I’m thinking maybe a recent shower or tap addition?

Edited: Or an immersion left on? Also this is a still, but on the video it spurts out

 

[John.g]

Hope its not also being used as a F&E tank.

 

[ShaunCorbs]

Hope its not also being used as a F&E tank.

why not ?

 

[John.g]

3 stage fernox may not be the best for washing ones hair with?.

 

[ShaunCorbs]

3 stage fernox may not be the best for washing ones hair with?.

thermal store

 

[Graham_84]

Its a thermal store tank that basically depicted below. Domestic water is via coil

Header is purely there to refil heating and and expansion of hot water.. Just curios why its suddenly now expanding after drain and refil.

Have i failed to bleed anything? like what is this bit in the other pic coming from the motorised Y valve.

Or any other suggestions

 

[John.g]

Is this UPS pump circulating the store water only through the boiler?. and if so what is the purpose of the diverter valve, assume you have another pump for the CH system of rads/UFH.

 

[Graham_84]

So the pump is for both.

My guess is
When HW is only on the diverter purely pumps water from take back to boiler. When CH is also on then the diverter allows water onwards through the Radiators. A complete guess. But all i know is one pump, and i can have HW/CH both on individually.

 

[John.g]

Could be...... you might check if you just have a 3 way diverter valve (not mid position) so wonder where the expansion is taken up if on rads only, expansion vessel? in boiler or open vented. Simply reducing the pump speed may help.