Kink in microbore

[reb78]

Whilst doing bits around our new house, I’ve noticed quite a major kink in some copper microbore heating pipe as it passes round a 90 degree bend. Why anyone uses this stuff is beyond me, but can I do anything about the kink or does it need a drain, cut and 90 degree bend soldering in? It’s an awkward spot as the kink is just as the pipe passes into a wall.

 

[Farside]

Horrible stuff, I agree. If it's only feeding a small rad, it might be passing enough flow to keep it hot enough; otherwise it's a cut-out and solder-in job.

 

[frank horton]

if it's diff to get at it with a heat torch......."use Hep2o"......it's a top quality plastic tube, get the plastic push on ends and the job's done........just make sure there are no BURR's........
of course if it's been woring OK just leave it........!!!!!!!!!!!!
Frank

 

[reb78]

Thanks chaps. I’m still figuring out the system but there are several roads that barely get hot at all and I’m wondering if they’re fed via this pipe. There may be more of these bad bends given the amount of microbore I think they’ve used!

 

[pedrobedro]

You could use pipe freeze and compression fittings. It's sometimes easier to replace a length than just repair a little bit.

 

[gaz1]

have you done what i suggested on the other thread?

http://www.mig-welding.co.uk/forum/threads/three-cold-rads.77389/page-2

any bad kinks its a cut out and replace them if theres many of them its a drain down

 

[hunter27]

Nowt wrong with 10mm copper if it is installed correctly (not to long a run to a radiator dependant on it's output) Plastic has more problem with blocking on central heating systems than copper and if it has ever been kinked it creates a permanent weakness to the pipe, the id of plastic is also less than copper so less flow.

Is your system sealed or open vented ? if open vented it can be quite easy to do, turn off the system, bung the expansion tank's cold feed and expansion pipes,(you can buy or make bungs) shut off the rad valve on the radiator being supplied by the kinked pipe and open a drain/vent on a near-by rad to drop the pressure, only expect a little bit of water while it creates a negative pressure in the system. Don't cut the pipe if the flow does not stop at this point.

Assuming the kink is just as the pipe enters the wall near the rad be prepared to replace your bit of pipe probably through the wall as well, have a dish under the pipe and a few wipers, cut the pipe in a good position and replace it.
You can use compression fittings if you get a few drips coming through but I have usually been able to solder the joints providing you can raise the pipe a bit to prevent water dripping into joint. As you probably know you can't solder if there is any amount of water in there and if you do solder make sure you have an open end to let the expanding steam out or it will blow pin holes through your solder.

If it's a combi sealed system you can do the same by turning of the valves under the boiler but some times that causes them to leak so I would avoid that if at all possible.

If its a sealed system with the pressure vessel out side the boiler I would just drain down to do the job.
It has probably took longer to type this that to do the job

pete

 

[Seadog]

I've fed individual rads using 8mm tee'd off 15mm. No problems at all.

 

[reb78]

have you done what i suggested on the other thread?

http://www.mig-welding.co.uk/forum/threads/three-cold-rads.77389/page-2

any bad kinks its a cut out and replace them if theres many of them its a drain down

Yes, although I’m not sure I have got the order quite right. One of the rads remains cold, the others are a little warmer. We did take them off and flush them and they were quite silted up.

 

[reb78]

Nowt wrong with 10mm copper if it is installed correctly (not to long a run to a radiator dependant on it's output) Plastic has more problem with blocking on central heating systems than copper and if it has ever been kinked it creates a permanent weakness to the pipe, the id of plastic is also less than copper so less flow.

Is your system sealed or open vented ? if open vented it can be quite easy to do, turn off the system, bung the expansion tank's cold feed and expansion pipes,(you can buy or make bungs) shut off the rad valve on the radiator being supplied by the kinked pipe and open a drain/vent on a near-by rad to drop the pressure, only expect a little bit of water while it creates a negative pressure in the system. Don't cut the pipe if the flow does not stop at this point.

Assuming the kink is just as the pipe enters the wall near the rad be prepared to replace your bit of pipe probably through the wall as well, have a dish under the pipe and a few wipers, cut the pipe in a good position and replace it.
You can use compression fittings if you get a few drips coming through but I have usually been able to solder the joints providing you can raise the pipe a bit to prevent water dripping into joint. As you probably know you can't solder if there is any amount of water in there and if you do solder make sure you have an open end to let the expanding steam out or it will blow pin holes through your solder.

If it's a combi sealed system you can do the same by turning of the valves under the boiler but some times that causes them to leak so I would avoid that if at all possible.

If its a sealed system with the pressure vessel out side the boiler I would just drain down to do the job.
It has probably took longer to type this that to do the job

pete

Haha. Thanks. I can’t work the system out. It seems to have an expansion tank and a pressure vessel.

They’ve used a lot long runs of the microbore unfortunately. I think they’ve cobbled the extension on to the existing system and not thought it out very well.

 

[gaz1]

is your system within a bungerlow or a house

more important question is there any rad near the boiler say 3 metre in piping as this radiator will return the flow quickly shutting down the boiler early is there a thermostatic valve on it?

 

[dazza]

I've had problems with a few rads right on the end of the run upstairs mainly because the pipes are run around the ceiling then drop down to the rads.

I had to close the valves on all the other rads to get the air out of these rads. Then to keep them going i closed the return valves on the rads closer to the boiler its been working for about a week now without any cold rads.

 

[angellonewolf]

have you ever had the system balanced

 

[angellonewolf]

micro bore is ok but normaly when new if its kept toped up with fernox can normaly last for quite a few years but after 10 ish years you start to see problems if not got the addatives way sooner

 

[8ob]

if it's diff to get at it with a heat torch......."use Hep2o"......it's a top quality plastic tube, get the plastic push on ends and the job's done........just make sure there are no BURR's........
of course if it's been woring OK just leave it........!!!!!!!!!!!!
Frank

Not so sure about this plastic malarkey Frank, my sister was having some work done at her house and when the painters took the rads off the upstands just cracked in half flooding the place. All the plastic installed less than ten years ago has age/use hardened.
Seems that as usual the public are the guineapigs and wonder how many of the companies producing this gear will be about to service warranty/damages claims in the years to come , give me copper tube any time.

Bob

 

[angellonewolf]

i can see a few jobs for plumbers over the next 10/20 years leaking pipe work and they will not want the job as the pipe ages the joints will not like the movement a leak near the rad when he takes it apart to fix it disturbs the one a meter away once hes gone a wet patch appears 3 days after hes gone gets called back so on so on

 

[brightspark]

plastics crap and allways will be. its cheap and fast thats why plumbers love it .all my house is in copper and heating in microbore and no leaks in over 30 years . its well proven

 

[gaz1]

with central heating systems I ask one question how old is your central heating system

plastic only guaranteed for so many years i think its 5 with older plastics new fittings are 10 years rubber seals perish if you move them

if older than a certain years i then explain that fixing that may cause others to leak due to its age

ive had it where a person said it worked before you touched it comment then ive explained it didnt as it was silted up to the eyeballs and really needed a new rad fitted which of coarse you wouldnt pay for so it got flushed out as best as could be

ive also had fittings that was soldered but leaked after other pipes was fitted when you check the fitting its had a 2mm ring around its fitting just holding on ive come across fittings that are just held on with just flux before now

last one i just did was 14 years old never been serviced silted up badly fitted rad right next door to thermostat

it took all day to flush the system using mains pressure through all pipes and each rad taken off and flushed through and to top it off when setting the balance the rad valves leak a fraction and yet owner wont pay for them the system is nearly like new

 

[optima21]

plastics crap and allways will be. its cheap and fast thats why plumbers love it .all my house is in copper and heating in microbore and no leaks in over 30 years . its well proven

same here, mine will be 40 years old next year

 

[rtbcomp]

My dad had a microbore system that worked well. One circuit per radiator fed from a manifold. IIRC balancing was done at the manifold.