Sytem recently power flushed,now new pump sucking in air-please help

[PSH]

Hi all,I am new to this forum. Just to give you a quick low down on what has happened so far. My Mother had a guy round to remove sludge in the central heating pipes which had practically stopped any water flow round the system ,and all but three of her rads remained cold. He refused to power flush her system because he said her system is micro-bore and would not stand the force ,so he dosed her system with chemicals and left her pump running for 3 days and came back expecting all the sludge to have gone.(I personally could not see how this would work as his chemicals would not be able to flow around her system ,so would not reach the blockages to break down the sludge, am i right ?) Any way ,he came back and there was no flow at all and all rads were stone cold. He turned the pump around several times to reverse flow the water to try and force sludge out,but this failed. He said that she needed all her pipes replacing with 15mm ones as flushing was not an option.

So I went through Age UK and this time got a "trusted" flushing firm round who said all it needed was to power flush her system and it was safe to do so. This second engineer successfully forced all the sluge out and got all her rads hot within 4 hours . He renewed her old pump as it had totally siezed up due to it running dry for too long caused by the sludge not allowing any water through it. This second enginner was un sure as to whether the first guy had put back the pump the right way round,but all seemed fine when he left ,and all rads were piping hot ,but after an hour ,all the rads went cold,even with the pump and boiler still running. I rang the guy up ,and he got me to bleed the new pump,which seemed to get all rads hot again. but they all went cold again after another hour,so he said he will come back to turn the pump around the other way,to see if that cures the problem.He also suspected air was being sucked in from the open vent,and suggested it might need an auto-bleed valve fitting to open vent,(what do you think of his suggestion guys)

My questiosn to you guys are ,has this new pump got a self venting valve ,as he told me to undo the black nut on top of unit and press it in ,which did release air.The pump is fitted on the return run.When i released the air form the pump a load of water shot out of the open vent and into the header tank,and continued to do this for a few minutes after system was running again.

Is the new pump sucking in air ,causing the rads to run cold after a while.
Please Help!

 

[shorticus]

Shorticus,I am please you think it all looks ok.It all seems to be working ok now,with all rads nice and hot. The only thing which concerns me now is the temperature of the hot water coming out her hot water taps. Both guys reckoned that the boiler stat has gone out of calibration,as it needs to be turned down to "minimum" on the dial,in order to stop my Mum from scolding herself . The rads are nice and hot on the minimum setting also. Do you think we should get the stat replaced ? how much are we talking ?

I never noticed before how thin the jacket was on my Mums cylinder until we removed all her clothes and linen and stuff which she had smothered the cylinder with. B&Q are selling cylinder jackets for £3.00 each ,so i will get one of them and fit some time soon. The pipework in her attic is usually well covered with 6" of insulation,and i will replace it once i am sure there are no leaks or further work needed.

Gasman,do you suspect that an old pump has been fitted ?

Absolutely get that stat replaced, probably less than 30 quid for the stat then an hours rate for someone, the loft insulation alone is not enough for those pipes and if those jackets are less than a fiver get two!!

 

[PSH]

Paul, i can honestly say that my Mums central heating has never performed so well since having the power flush, and her bungalow is now nice and warm, a bit too hot for me actually. I think her system must have been sludging up for quite a few years , as one by one her rads have been dying ,and now for the first time they all work(touch wood). I asked the last guy that came to do the power flush what he thought of the system in general and he said the soldered joints all looked good and should be stronger than the pipe itself, and all the pipe bends had large radii and were smooth and flowed out nicely . My Mum has decided to move into a sheltered accommodation nearer to me in the new year , otherwise we would have considered replacing the whole system.

Gasman, the pump certainly looks new and i have the box it came in just in case it needs to be replaced.

Shorticus, I will look into getting the boiler stat replaced, and lag those pipes in the attic properly. Now which type of fabric conditioner, Lenor or comfort,(Grin)

 

[PSH]

Paul, I forgot to add that I got the power flush done for £430.00 by going through Age UK,which i thought was pretty good compared with £700 + which British Gas wanted.

 

[FD Powerflow]

It was probably just the pump being the wrong way round which would give it a negative head and suck air in from the F&E tank instead of pushing water round the system. This would cause air locks and more importantly rot the system by accelerating the corrosion of the rads massively. Best way to check would be to have a look in the vent pipe and see if its almost blocked up with magnetite.

 

[Heating-eng]

Paul it's all about opinions here and yours is as valid as anyone elses, I have a different one but hey that's all part of being human.
I'm gonna make you roll with laughter now but many years ago (probably too many to mention) and this is a true story, I worked for a fella who used to dose heating systems, particularly microbore, with fabric conditioner!! This was a long time before powerflushing had been invented so we would flush the systems with raw water, take the rads off knock 'em about a bit, flush them out in the garden pop 'em back in, dose with lenor or comfort then get this, he'd pull out the stat phile and run the boiler up (usually solid fuel) 'till the pipes rattled!!!
He reckoned that he'd been doing it for years and had never had to return to a sluged up system that he'd performed his miracle proceedure on, scared the living daylights outta me and my college tutors simply fell silent when I told them, made the loft smell nice though😀


DIYers, please note, I DO NOT RECOMMEND THIS PROCEDURE!!!!!!

Does this work LOL, be cheaper ....

 

[PSH]

Hi,just to update you all, my Mums radiators are still running nice and hot (touch wood),with just the odd bit of bleeding required.The guy who did the power flushing asked me to turn the pump speed setting down to the mid way postion ,in case the pump is running too fast and is aerating the water, producing air bubbles.

I have fitted propper pipe insulation to all exposed pipe work in attic and fitted 2 new jackets to the storage tank. I am checking the magna flush filter regualary and have noticed that with each clean ,it is collecting less black sludge,which must be a sign that the water in the system is getting cleaner.

The guy who did the power flushing has agreed to come back and replace the boiler stat.

I have noticed that the ball valve in the heating header tank has a small leak,one drip every 15 seconds,which is being handled ok by the over flow pipe. I have replaced the small round black washers before in these valves ,but wanted to ask you guys if you think i should renew the whole assembly or just renew the washer ?