How to remove a stuck push fitting? And plinth heaters...

[hellopaul2]

Hello,
I have a plinth heater (similar to this: https://www.plumbnation.co.uk/site/smith-s-space-saver-ss5-fan-convector---kitchen-plinth-heater/) in my kitchen, connected to my central heating water. It does not work, and I want to remove it to check if there's a blockage. The fan runs OK, but only blows cold, even when the central heating is running. One of the pipes to the heater gets warm (presumably the flow) but the return pipe remains stone cold, so there is obviously no flow through the thing.
So, I've read various things about these heaters, from "I never use mine" to "they're great", and seeing as there is no other heating other than two of these plinth heaters (the other one doesn't work either, but I haven'd pulled out the unit that one's mounted in yet), I'd like to disconnect the first one and connect it to a hose or something to see if there's a blockage that I can dislodge. BUT, the push fit connectors are impossible to budge. Any suggestions on how I might be able to remove the stupid things? They are on the end of flexible hoses connected one end to the heater unit and the other end to the CH pipework. The flexi hoses have a shutoff valve at the heater end, which I've obviously now closed before I remove things!
Any suggestions would be most welcome!

 

[alan333]

I'm sure you're aware of this, but just in case...
The red collar needs pushed back towards the black body of the fitting, then the pipe should come out fairly easily.

 

[hellopaul2]

Yeah, I've tried pushing that red collar back - using my fingers and an adjustable spanner (to give it more "welly"). It moves back a bit, but the pipe will not move at all. I've read suggestions about pushing the pipe into the fitting before pulling it out, but I can't do that, either. It's like it's been Araldited in there .

 

[John D v2.0]

probably crudded around, I find they stick on copper more than plastic pipe, but a good technique is to use a pipe clip to push the collar back effectively. Then a comination of push, twist and pull eventually loosens it. Twist the pipe relative to the push ring as thats what the metal "teeth" are on that's gripping the pipe.
Good luck!
When you reassemble, use a dab of silicone plumbing grease on the end of the pipe. You're not supposed to, but the only push fit leak I had was when I stopped doing that as it dislodged the o ring.

 

[hellopaul2]

Thanks for the suggestions, @John D v2.0 . I found a pipe clip - the only ones I have are for 22mm pipes, not the 15mm pipes connected to the thing, but think it helped - a combination of pipe clip, adjustable spanner, finger pain and lots of swearing helped remove one of the pipes, but the second one still refuses to budge. Annoyingly, despite both valves being turned to the off position, a drip-drip-drip of water still flowed through the unit, so it's now sitting on a bucket, awaiting a plumber to come and attack it, probably when I've pulled the kitchen unit housing the second heater out, so he can kill two heaters with one stone. I should stick to my mantra of "I do some work, doing what I do (graphic design, websites, visual effects) to earn money to pay other people to do what they do" more consistently!

I've just got to figure the timing of removing the other kitchen units, getting a plumber in to look at the heaters, getting some new worktop, a new sink, and fitting everything together with minimal kitchen-sink-downtime!

 

[John D v2.0]

If you're learning something interesting, carry on, if you're not enjoying it, pay someone else. But finding someone decent and sorting things out when they aren't could be less fun than actually doing it yourself...
Glad you're making progress! Good luck.

 

[RigidRaider]

I've heard that those plinth heaters have such narrow galleries that they make excellent traps for any crap that's whizzing around in your heating circuit. Being the lowest part of the system helps a lot.

 

[John D v2.0]

I've heard that those plinth heaters have such narrow galleries that they make excellent traps for any crap that's whizzing around in your heating circuit. Being the lowest part of the system helps a lot.

Does make you wonder- we have auto air vents at the top to collect all the air, so why not have a sump with mesh at the bottom to collect all the sludge?
Maybe it would have to be too big because sludge isn't as heavy as air is light?
Those magnaclean things work OK but they don't take it all out.