Problems with small bore pipe and an old central heating system

[jh2254]

The small bore pipe to 4 radiators was completely clogged up. One radiator stone cold , others barely luke warm. Those plumbers that bothered to quote said ‘power flush’ but would not guarantee any success. So I tackled it myself, ripped up the floor boards and traced back the small bore that joined onto the 15mm pipe in the upstairs (under the floor boards). Opened the pipe from the 15mm to small bore connection and out glugged what you see in the picture - it was an inch thick! Bought some small guage garden wire and began rodding the pipes from the kitchen. Eventually managed to get the wire up 8 foot , but still no water flow. Then rodded down from above. After 5 hours of rodding each 8 foot pipe length I broke through ! Did this for all 4 radiators , both flow and return. I reassembled and ran cleaner through for 2 weeks. Drained and put inhibitor in. After a few days all 4 radiators clogged again !
So I fitted a magnaclean to the flow on one of the radiators and wow 🤩 what a difference it made to catching the magnetite before it entered the flow pipe into the radiators.
Now just got to attach another magnaclean to two other radiators that are served by the same bit of pipe and hopefully that will solve the problem.
The last radiator I will tackle later.
Fortunately I have enough space between the ceiling and the floor boards upstairs to fit a magnaclean (I dont use the drain hole in the magnaclean but a large syringe to empty the container and the magnaclean stands vertical no problem!).
Would appreciate forum members opinions on whether I should have done anything different ! Has this solution been used before!
And the answer was not to move house !
What a nightmare it’s been !
Thank you.

 

[oz-plumber]

Nice work.
With that much muck in the system, I would be keeping a close eye on the radiators.
They might start pinging leaks!!

 

[John.g]

Looks like the 4 rads are now inside in that white container.

 

[ShaunCorbs]

X 800 in for a week and run the system then mains flush it out one rad at a time eg close all but one trv / lockshield and open a drain off etc

 

[jh2254]

Thanks. Yes I did use

X 800 in for a week and run the system then mains flush it out one rad at a time eg close all but one trv / lockshield and open a drain off etc

x800 for about 2 weeks but I should have done mains flushing of each rad. That’s where I think I went wrong 😑. I just closed one valve on each rad and then opened the drain valve and let it flush through at system pressure (gravity). Will need to do again I think. Thanks.

 

[jh2254]

Looks like the 4 rads are now inside in that white container.

Yes 😂🤣

 

[jh2254]

I have now fitted the second magnaclean on the flow pipe just before the 15mm plastic pipe joins the small bore that serves 2 more radiators. Refilled the system, adding the cleaner and fired up the bolier. All the rads now work and the magnaclean is collecting small amounts of magnetite. The problem I have now is that after balancing the rads the 2 rads that have the small bore which are right at the end of the system are taking an hour to come on ?
Do I need a more powerful pump for the 5 bed house (21 rads) that has had 3 extensions?
I have the boiler (glowworm ultimate 70 ff) set to max temperature. A grundfos super selectric UPS 15-60 130 which must be about 10 to 15 years old.
Perhaps the existing pump is not as strong at pushing the water around ? Would a new pump improve the water flow? Many thanks.

 

[John.g]

Nice work jh, before throwing out that magnificent super selectric I would certainly remove the head (you may already have done so) and clean the impeller vanes and pump ports and back flush from both ends.

 

[jh2254]

Nice work jh, before throwing out that magnificent super selectric I would certainly remove the head (you may already have done so) and clean the impeller vanes and pump ports and back flush from both ends.

Thanks John. I have not removed the head yet. How do I do this please? Thanks.

 

[John.g]

Obviously shut suction&discharge pump valves, there will be probably 4 (but maybe just 2) stud bolts (allen key head) holding the pump head onto the body, just remove these and the head, complete with impeller should come off, you may have to gently prise it after all these years. Post a photo pre&after clean please.

 

[jh2254]

Obviously shut suction&discharge pump valves, there will be probably 4 (but maybe just 2) stud bolts (allen key head) holding the pump head onto the body, just remove these and the head, complete with impeller should come off, you may have to gently prise it after all these years. Post a photo pre&after clean please.

Thanks John. Job for tomorrow. Will post before and after pics.

 

[jh2254]

Thanks John. Job for tomorrow. Will post before and after pics.

Top valve before. Something tells me I am going to have a problem as its already been leaking!

 

[jh2254]

Top valve before. Something tells me I am going to have a problem as its already been leaking!

Main body - before

 

[jh2254]

Main body - before

Bottom valve - before

 

[John.g]

You may be able to nip up the gland nut(s) a touch to stop the leak, to ensure the valve seats don;t leak, open and shut each valve say 4 or 5 times then with both shut remove the vent plug and ensure water stops before removing pump head.

 

[jh2254]

You may be able to nip up the gland nut(s) a touch to stop the leak, to ensure the valve seats don;t leak, open and shut each valve say 4 or 5 times then with both shut remove the vent plug and ensure water stops before removing pump head.

OK thanks. Going to start tomorrow morning in the light.

 

[jh2254]

Now started the job of cleaning the pump. I closed the top and bottom valves and removed the bleed screw. Hardly any water came out. I then opened the top valve fully - still just a drip drip from the bleed valve. I then opened the bottom valve , still just a drip drip. Attached is the picture of the water I caught after opening the bleed valve for 5 minutes. I also put a magnet up to the pipes and it stuck like glue. Do I have a major problem on my hands ? Is this the reason the small bore pipe (now rodded clean) radiators take over an hour to get warm?

 

[jh2254]

opening the bleed screw and hardly any water came out?

 

[jh2254]

View attachment 78017

 

[John.g]

Can,t open attachment but its normal for only a dribble to come out of the vent screw.

Just remove the pump head and have a look inside.

 

[jh2254]

Can,t open attachment but its normal for only a dribble to come out of the vent screw.

Just remove the pump head and have a look inside.

OK thanks. I also opened the top and bottom valves and still only a trickle? Is this normal? Also I was a little worried that the magnet stuck like glue to the copper pipe just to the left of the bottom valve - does this show that its full of magnetite?

 

[John.g]

Yes, its quite normal for only a dribble to come out of the vent with both valves open as the end of the pump shaft is inside this vent plug.
You will either have to remove the pump complete or for a start just remove the pump head (far easier) to check for magnetite build up or whatever.

 

[ShaunCorbs]

A magnet shouldn’t stick to copper so yes blocked

 

[jh2254]

Yes, its quite normal for only a dribble to come out of the vent with both valves open as the end of the pump shaft is inside this vent plug.
You will either have to remove the pump complete or for a start just remove the pump head (far easier) to check for magnetite build up or whatever.

Tried to remove the pump head only by trying to crack open the 4 bolts. First bolt I tried would not budge using a small allen key. Then put a set of mole grips on and tried. Still did not budge. Should I use full force or is that likely to shear the bolt head? Just thought I would ask in advance! Surely it should not take that much force? Thanks.

 

[ShaunCorbs]

Undo the unions ?