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!

 

[tipintim]

1.What boiler is it
2. What pump is it and where is it positioned (vent on top ? )
3. Can you post a photo of the system
4. How old is the system

Sounds to me that this issue is from when it was first fitted/installed
Went to one recently with similar problems, only to find out it was originally a 1 pipe system poorly converted.

 

[PSH]

Hi tipintim, I do not live any where near my Mums house,and i am not able to call round to take any snaps or get the make of the pump which the last guy fitted,until this wednesday evening ,but going from memory,i am fairly sure she has a 20 year old Potterton Kingfisher. The rest of the system is circa 1965 and is a double pipe system where several pipes run out from the supply mainifold ,fanning out to each rad individually and then back to the return manifold. The pump is located in the return feed just after the manifold in the attic just above the storage tank with it's bleed nut and speed control on top(upper most).The new pump is black and is smaller that the original Grunfos.
1. Should the black bleed nut be left slightly loose in order for the pump to auto vent ?
2. Why did a load of water bomb out of the vent pipe into the header tank when i vented the pump,and is this normal ?
3. Do you think the pump is sucking in air because the pump is mounted the wrong way round,as this system ran ok before with no air lock probs ?
4. Would fitting an auto vent be a good move anyway,and self vent the system and still allow water to be vented into the header ,if this is normal ?
5.As i am new to forum,how do a post a photo.

 

[tipintim]

1. The bleed nut you talk about is a manual way to vent the pump and to check if the shaft is spinning. After venting it gets screwed back in place. To my knolwedge its not good practice to fit the pump with the vent on top. It will trap air. You could turn it to ist side. Really need a picture to see what you got.

2. Water bombed out cause you manually vented and caused the pump to surge water not air.

3. It could well be sucking. Try turning the pump down. Was the last one a water mover or a pump? Is the vent pipe high enough?
How many header tanks have you got in the attic? Is it a seperate feed and expansion for the heating system?

4. Because the pump is in an attic, it should have vents .

5. Not too sure my self. Some one can help you with that one

 

[PSH]

1. When i manually vented the pump,I had to slightly unscrew the nut and press down hard on nut.The engineer is at my Mothers house ,at this very moment fitting an auto air bleed valve ,which he says should stop the pump sucking in air.He is also going to turn the pump around to see if it works better ,as he replaced it ,the same as the last guy had left it. At the moment ,i will delay mentioning to the guy about not fitting the pump with it's vent valve on the top,as i dont want to annoy him.i will try to take some snaps wednesday night and post them next day.
3.It had a Grundfos pump previously.The vent pipe travels up about 4 foot,then loops over to feed into top of tank. there are two tanks,one large one for the hot taps etc,and one small one for heating system.Will have to check tomorrow about about the feeds.

i will let you know if the guy is successful today or not,fingers crossed he will be ,because my Mum is very cold and at her wits end with all this carry on,having to have two firms in,and I am not looking forward to negotiating with the first guy as he will no doublt want full apyment for his work even though he did not do what he was contracted to do .dont get me wrong,I do intend paying him for re-valving and re-pipeing all her rads,just not sure how much to barter him down by,any suggestions ?

 

[Js58gas]

Hi you need to find out when the flush was done did they cut out the airsep or h section as this is where a system will block up the most. If they have not this could be restricted still and cause air to be pulled in.

 

[shorticus]

'and suggested it might need an auto-bleed valve fitting to open vent' this quote makes me nervous, we definitely need a pic of the remedials

 

[PSH]

Just to update you all,I know it's early days,but the guy came back nice and early yesterday and fitted an auto bleed vent on the same section of pipe that the pump sits on ,at the highest point and after that the whole system heated up a treat and remained hot while he replaced the "holed" rad in my Mothers dining room.He took his time doing this to give the system plenty of time to fail,and also modified the "open vent" pipe so that it went straight in through the side of the header tank,as before when water surged up and out the top,the pipe jerked about that much that some water missed the tank. As of 10.00pm last night ,when i spoke to my Mother,all her rads were still hot (Touch wood).I am popping round tonight to take a look at what he has done and will take some snaps to add to this post. I will have to check this sites "help" section to find out how to post photo's.

Has anyone got any suggestions as to what would be a fair amount to pay the first guy who came round and failed to un-sludge the system ?

Shoticus,why does the idea of fitting an auto vent make you nervous ?,it seems to have done the trick.

 

[shorticus]

...it may just be my interpretation of your post hence my request for a pic, open vents should be just that, open. If the system is over pumping and rattling around that vent pipe then a re-route through the side of the header tank, IMO, is not the answer, vents should have height to allow for expansion and contraction of the heating medium without spilling over. The over pumping is indicative of an abnormality. You describe it as an old system, has it always had issues or has it worked well for many years prior to the sludge problem? Has any of your visitors checked the boiler? Sorry for the barrage of questions but I'm struggling to envisage the layout, microbore systems are a pain in the derriere if not maintained properly but that doesn't necessarily mean that the pipework layout or ancillaries need a re-design.
I think we need those pics...

 

[sheff paul]

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!

If it is old micro bore,you are throwing money away trying to flush it,now you have got air sucking in it will corrode your rads far quicker,and create even more sludge.Better off going for a new system

 

[PSH]

Js58gas, the engineer assures me that there are no blockages anymore, and no need to cut out any airseps or, or "H" sections.

Shorticus, I have hopefully attached some snaps somewhere on this post. I had a look at the modified open vent pipe last night and the engineers description was a bit off. All he has done is extend the original open pipe,so that it now bends over into the top of the tank,and is at least four feet long from connection to end,and is not blocked.The water only surged out while i was manually bleeding the pump,and the water was very hot.Under normal running it does not do this.The system has worked well for the last 35 years that my Mother has lived there and only developed cold rads during the last few years caused by sludge build up. Both visiting engineers have checked out the boiler,and said although it's old,is still working fine,and now runs fairly quietly since the proper power flush was carried out .

Tipintim, the new pump is a SMC Gold.

I feel a bit of a fraud now and feel i am wasting all your guys time,as when i originally posted, the first guy seemed to have totally cocked the whole system up and was advising a total repipe of the whole bungalow,and even though the second guy had successfully removed all sludge by powerflushing the system ,i had the feeling things were going to get worse,and thought i had better get some help form you guys. However ,since the last guy fitted this auto air vent on an extended piece of tubing,connected to the high point of the system, all the rads have remained hot for two days now ,with no obvious problems (touch wood). So maybe the system is now back up and running again,and it's all sorted.i am curious to see what you all make of my snaps.

 

[sheff paul]

whats the tray for under the pump,looks like you are ready for a new system?

 

[PSH]

I put the tray there while i emptied out the magna filter (black cylinder),so that it did'nt drip on the clothes. As far as i can see,there are no leaks.

 

[shorticus]

PSH, you're not wasting anyones time and thanks for the pics they've really helped, I'm now quite relieved, it actually looks ok (layout/function wise) I'm not a fan of plastic fittings but I know a lot of guys don't like taking a blow torch into a loft, the pipework is bit up and down and it aint pretty, but then again neither am I

I'd recommend getting some proper pipe lagging and a decent cylinder jacket, your poor Mum must be spending a fortune heating that loft, oh and when she has her annual boiler service get them to check the inhibitor levels too, no reason why it shouldn't last another 35years.

Shorty

 

[PowerFlushAssoc]

In general: power flushing micro bore is never straight forward and result vary greatly, sometimes failing to work at all.

The auto air vent will automatically bleed out air from the pump and the vent pipe extension will keep the system from over pumping. Pipe lagging is a good idea. Clean the magnetic filter regularly, in the beginning, until there is very little sludge on it. Make sure you keep inhibitor levels high - always.

 

[Billy Bob Bob]

smc gold the pump make? i thought smc went years ago,on a google search its a cp/myson/flowson/smc

 

[PSH]

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 ?

 

[sheff paul]

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 ?

Looks like i am going against the general concencus here,but i have ripped out far better systems than that,i know old people dont like up heavel and all that but i would hate to see her gas bills and level of comfort she has,but power flushing is never going to make an old system new again see too many over priced power flushes and 6 months later same problem again,(sorry to upset anyone),3500 spent on a new system would be a good investment even in these troubled times.surprised to see others not stating the obvious here

 

[shorticus]

Looks like i am going against the general concencus here,but i have ripped out far better systems than that,i know old people dont like up heavel and all that but i would hate to see her gas bills and level of comfort she has,but power flushing is never going to make an old system new again see too many over priced power flushes and 6 months later same problem again,(sorry to upset anyone),3500 spent on a new system would be a good investment even in these troubled times.surprised to see others not stating the obvious here

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!!!!!!

 

[Billy Bob Bob]

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

no it looks brand new looks like the old name SMC is getting a revive

 

[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 ....