New Rads

[NewhouseOldhouse]

Hi

I got an old oil boiler replaced with a new grant votex boiler and the system is now pressurised which was previously gravity fed.

It's a bungalow and I have a mix of micro bore rads and 15mm run from boiler for new rads some under floor piping anf some up and down from loft.

Everything I turn heating on the a section of new rads seem to have air in 15mm runs - the pipe to TVR is heating but the lock shield side is cold.

I have also several Flamco valves on the micro bore side and 15mm side.

To resolve the issue I have to turn of all rads and gradually turn on the rads that don't heat 1 by 1 to eventually all are on.

The new pump on the boiler is a 8mtr head pump.

Anyone any advice so when I turn heating on all rads heat each time?

If its a pressurised system and all air is out why would air be getting in?

 

[Johntheo5]

Is the E.vessel connected into the Boiler Flow or Return?.
What is the pump mode and setting?. (also make/model)

 

[NewhouseOldhouse]

Is the E.vessel connected into the Boiler Flow or Return?.
What is the pump mode and setting?. (also make/model)

Not sure what the E.vessel is if it's the red thing where I check the pressure not sure if it's on the flow or return, how would i check this?

The pump is picture and setting its on is attached

 

[Johntheo5]

Yes, the E.vessel is the red vessel, with the boiler running feel the main pipe that the E,vessel pipe is attached to and compare its temperature with the other main pipe, if the pipe its attached to is colder than the other pipe then its connected into the return. Is the E.vessel connected in close to the pump and what pressure is it showing when cold.
Get somebody to start/stop the boiler and see does the pressure change up or down when the boiler/pump starts up,

 

[NewhouseOldhouse]

The E.vessel is beside the water tank in loft not near pump nor boiler. When cold the pressure is 1.2 but when heating on can go up to about 1.8 or so.

No movement in the when the boiler/pump starts just gradually goes up when heating on for a while.

 

[Exedon]

As above what setting is the pump on?
That's a Dab decent pump press mode button once it will show mode its on.
If you have lots of air and non circulation push button to get constant curve 3 when system working pump can be turned down to something more appropriate.
Are the the caps on the auto air vents open?

 

[Johntheo5]

The pump in the picture is showing constant curve and with it, looks like 3 white LEDS which is "full speed" and if it is a 8M pump (I know the Evosta 3 can be a 8M pump but didnt know that the Evosta 2 could be a 8M) then IMO its far too high a setting, if we could see the pump curves then can suggest a appropriate setting but CC1 or at the most CC2 should be more than adequate?.
Is the pump orientated correctly, ie if installed on the boiler flow the arrow on the pump body points away from the boiler, if on the boiler return, it points into the boiler.

How many rads on the system?

 

[NewhouseOldhouse]

Pump is Evostat 2 on setting constant curve 3 and yes pump is installed correctly.

It is an 8m pump, would the high setting create air in the system?

 

[Johntheo5]

IMO, yes, why is it set to its highest setting of 8M?, is there a huge number of rads or is it because some rads are not heating sufficiently?.

 

[NewhouseOldhouse]

There are 19 rads on the system and some are not heating at all. It's the new 15mm ones I have installed there are 5 new ones and 3 are not heating.

The fella who installed the boiler left the pump at that setting. He got all heating few weeks back but only turned heating on today and 3 not heating. The pressure is good

 

[Johntheo5]

Maybe should have said earlier that if you are getting air ingress and not venting it then the boiler pressure should rise, if you are venting it regularly either manually or its venting through the Flamco valves? then the system should not need top up, if you have to top up after venting then there is still residual air in the system and it might eventually be gt rid of. Of course your system might be generating hydrogen gas if it was chemically cleaned before installing the new boiler+rads and wasn't thoroughly flushed out afterwards.

 

[NewhouseOldhouse]

Thanks for all the advice

 

[NewhouseOldhouse]

Update

i tried heating today turned off all rads but left one that wasnt heating on heated with good flow. turned this one off an turn on another one which wasnt heating heated.

i done this when i got all rads heating individually.

once i turn all rads on the same rads stop heating again.

any ideas?

 

[NewhouseOldhouse]

Yes, the E.vessel is the red vessel, with the boiler running feel the main pipe that the E,vessel pipe is attached to and compare its temperature with the other main pipe, if the pipe its attached to is colder than the other pipe then its connected into the return. Is the E.vessel connected in close to the pump and what pressure is it showing when cold.
Get somebody to start/stop the boiler and see does the pressure change up or down when the boiler/pump starts up,

the pipe the E.vessel is connected never heated at all?

 

[Johntheo5]

If its the actual pipe between the E.vessel and the main pipe then only a few litres (expansion) will move back and forth as the system is heating up and down over a fairly long period so wouldn't expect to feel any or much difference in temperature.

Did you have to vent air again to get these rads heating, if not then perhaps restriction /blockage somewhere, you might increase the system pressure by 0.5bar, if its hot and reading say 1.7bar just now increase it to 2.2 bar and try rads on their own again, its very strange that a 8M pump will only pump through these affected rads only when on their own.
Also suggest changing pump to CP (constant pressure) contro and a fairly low setting, maybe CP1.