Do I have air in the system?

[mucky]

Having just replaced a radiator with a towel heater, I have refilled the system having bled it.
However when I turn the boiler on it fires up for around 2 mins and then the cut off/reset switch trips, followed by a loud girgling of water.

I suspect there is air in the system and have bled every radiator.

Is there air in the system ? if so how can I clear it out?
The boiler is a Potterton Prima F

Any help appreciated.

Muck

 

[Softus]

Please describe the system in more detail.

For now, I'll assume that it's open vented and pumped, in which case you ought to check the state of the F&E tank before refilling. Drain the system again, with no cold supply to the F&E, and ensure that the F&E contents drain away.

Then stand over the F&E while the cold is turned back on, and watch while it refills, and make sure again that water is entering the system. If not, then you have a blockage - this is almost always at the point where the cold feed meets the circulating primary.

If no blockage, then bleed all rads BEFORE applying power to the pump. Then turn on and ensure that the pump is powered and rotating - if unsure about the latter then remove the screw cap (with a little bowl to hand) and observe the spindle turning.

If you've done all that and found no fault then post some more information and see what else the forum can offer.

If your problem goes away, then don't forget to drain again and add a chemical inhibitor to keep the system free of [further] corrosion.

 

[meldrew's_mate]

As posted, check the pump is operating as this sounds like lack of circulation.

 

[ollski]

You may have bled the rads but you also need to bleed the high points of the pipework, there will be one or more screw caps on the end of a length of vertical pipe...also your 3 port valve may have a manual setting to hook it on to open the rad circuit when you refill.

 

[mucky]

Yes the system is vented and pumped, The tank appeared to be filling and emptying in to the system, however I noticed that there there was plenty of gunge in the filler tank when it was re filling. It is possible that some of this could have entered the supply as the gauze filter has become dislodged.

I have carried out the filling procedue but will do it again tonight.

I will once again bleed all the rads.

The pump is working (I can hear it)

Based upon what you say here there may be a blockage to the supply to the boiler, I suspect there is not enough water getting in and it is then over heating.
Will chemical cleaner clear this? and if so where should I put it into the system, my guess is via the header tank.

Thanks so far, I will return

Muck

 

[slippyr4]

does the new rad get very hot? do your other rads get hot?

 

[mucky]

Initially when I first re filled the system the rad started to warm up as normal, then after 10 -15mins or so they just stopped heating up.
Now the boiler closes down before they have a chance to heat up. So I suspect that there maybe a blockage as described earlier, this blockage probably occurred whilst it was heating up the first time.

 

[mucky]

Hi again,
I have totally drained the system, and refilled it, flow from the expansion tank is ok.
The boiler fires up for 2 mins then shudders to a halt, the cut off trips under the boiler.
The pump appears to be operating correctly, there is no obvious reason for this problem, as it was working well before the rad change and the initial bleed down.

Muck

 

[ollski]

Much as I hate to go over old ground are you ceretain you have found all the bleed points in the system?....forget the rads, its the pipes you need to get the air out of.

 

[mucky]

Hi ollski,
There is 1 above the boiler, which appears to be linked to the header tank boiler feed pipe, but I can't see any others where would they normally be?

Muck

 

[mucky]

before the boiler turns off, the hot water gets from the boiler past the pump and up to the mid point valve in the airing cupboard. The pipes from this (1 to the tank and the other to the heating I suspect) are both cold whilst the feed is boiling hot.
Could this valve be faulty?
The valve was replaced about 4 years ago.

Thanks

 

[ollski]

before the boiler turns off, the hot water gets from the boiler past the pump and up to the mid point valve in the airing cupboard. The pipes from this (1 to the tank and the other to the heating I suspect) are both cold whilst the feed is boiling hot.
Could this valve be faulty?
The valve was replaced about 4 years ago.

Thanks

No a mid position valve can never be closed both ways, but you may well find that the bleed points are close to the valve or as previously said if you had the pump running full of air it will burn out in no time.

 

[mucky]

No I can't see any bleed valves near there, Why don't any of the 2 pipes from the MP Valve get hot? It really seems that the water won't get past it.

M

 

[ollski]

you have no more of these?:
http://www.bargainbuyz.co.uk/product_info.php?products_id=37

Have you found any?, if so have you bled the air out of them and are they now running through water or is nothing coming out at all??

 

[mucky]

Hi,
No the only bleed valves are on 4 of the downstairs radiator valves, there is nothing on any vertical pipes other than one above the boiler