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.

 

[John.g]

Unfortunately!, the pump impeller looks very clean, get a tie wrap and shove it it through each vane in the impeller (right hand picture) to ensure each one clear.

 

[jh2254]

Unfortunately!, the pump impeller looks very clean, get a tie wrap and shove it it through each vane in the impeller (right hand picture) to ensure each one clear.

OK thanks. Looks like the two magnacleans I fitted on the flow pipes to the small bore pipes is working! I am a little worried that the magnet stuck like glue (see large magnet) but perhaps I dont need to be worried as when I opened the bottom valve water flowed?
Also if I put x800 in the system for a few weeks would that help with the baked on magnetite in the copper pipe and any remaining in the small bore? If not then I may just have to live with the small bore rads at the end of the system taking an hour to come on? Thanks.

 

[John.g]

Can you post a picture of the Grundfos pump label and should then be able to figure out if a 5M or 6M pump, also, it should give the rating of the capacitor inside the terminal box, probably, 2.4uF, some say that when these start getting weak that while they will still start the pump but it will run slower and produce less head, you can also test this capacitor with some multimeters, might be worth renewing if one can be picked up cheap, otherwise maybe consider something like a DAB Evosta 3 for ~ £120.

 

[jh2254]

Can you post a picture of the Grundfos pump label and should then be able to figure out if a 5M or 6M pump, also, it should give the rating of the capacitor inside the terminal box, probably, 2.4uF, some say that when these start getting weak that while they will still start the pump but it will run slower and produce less head, you can also test this capacitor with some multimeters, might be worth renewing if one can be picked up cheap, otherwise maybe consider something like a DAB Evosta 3 for ~ £120.

This is it. I think its 6m? Is it worth running through some x800 for a few weeks to clear the film of magnetite in the system? Or is this not worth it? Thanks.

 

[ShaunCorbs]

If a magnet sticks x800 might help but won’t do much if it’s 1/2 restricted

 

[Ben-gee]

Use your magnet to investigate extent of blockage, depending on what you find- cut out and replace that section of pipe

 

[jh2254]

 

[jh2254]

Update. Central heating has now been running ok for the last few weeks with X800. Every few days I have been cleaning out the two magnacleans I installed. Last time was today after I left heating on timed (one hour in the morning and one hour in the evening) for the last 8 days. It collected magnetite as per the photos attached. Should I leave the X800 in for a few more weeks until it collects no more magnetite or drain and fill with inhibitor now ? Many thanks.

 

[jh2254]

Update. Now into December and with the X800 still in system I continue to collect weekly amounts of magnetite. See pictures. When is the right time to drain the system and add x100 ? Many thanks.

 

[jh2254]

Update (October 2023). System still running perfectly. I drained down in the summer and put new inhibitor in. Recently powered up and the central heating is running well. Still collecting the debris in the 2 magnacleans I fitted at the troublesome spots on the system (entry into the small bore pipes leading to the radiators that did not heat up) but I dont mind cleaning them out every month. Rather this than spend £2k on a power flush that is not guaranteed to work and may cause no end of problems on my 40 year old multi pipe (normal and small bore) system! Learnt a lot on this forum and if I had my time again would not have allowed these so called 'professional plumbers' to install small bore pipes in my system!! Thanks again. Cheers.