Options to fix cold radiator without lifting laminate?

Hi

Looking for some advice. We have an old rad (8mm microbore) in hall which was never mega warm. Last winter i noticed it was cooler but eventually got some heat in it by adjusting the return valve on the rad & balancing some other rads.

Have turned rad back on after summer and no heat. Even if all downstairs rads are off it is nt heating.

Findings so far:
1) The TRV and pipe work to the bottom of the rad gets burning hot.
2) hot water gets to the TRV on the problem rad as quickly as it does to the rad in our living room (both around same distance from boiler and at same end of house) - pipes at TRV heat up at same time.
3) we have replaced the radiator and both valves.
4) if i turn either of the valves when refilling the system, we can hear the water filling the rad fairly quickly. Cant upload the apple video but when squirting the water into the bottle it squirted out quickly.
5) we get some heat to the top of the rad but not much else.
6) i have attached some pics of the downstairs manifold. All rads either branch off the side or end of the 22mm pipe EXCEPT the problem hall rad branches off the underneath of the manifold (you may see the pipework flowing away from the manifold in the 2nd pic).

We are going to get a plumber from my work to fix but what options do we have before lifting the laminate to replace pipe work?

Things we have thought we could get done:
1) there is a spare branch off the side of tge manifold - do we move the pipework for the problem rad to here first to see if the water has not had the opportunity to flow quick enough back to the rad.
2) disconnect pipework at rad and manifold. Put a hose on either end with a jubilee clip and flush water through both pipes to check for blockages or force out blockages.

If above doesnt work, coukd we drill a bigger home in the laminate, tape new pipe to the old pipe and pull back to the manifold. But would 8mm microbore go down throught the floor and bend back towards the manifold (at a 90deg angle) with just being taped to the old pipe.

Is there any options i haven't thought of?

Any advice woukd be greatly appreciated before i have to lift the laminate and skirting.

Thanks
Fluff

I would try this first. Take rad off, open rad valve(s) into a dish, see what pressure your'e getting, this may free up any crud sitting in the pipework. Also attatch a hose and let it run whilst topping up system.

Have you tried a chemical clean with X400 yet?

If the problem is indeed due to a sediment blockage, that will help loosen it.

When did the rad last work correctly? Has an extra radiator been put on the same pipe?

Turn off ALL the other radiators in the house. Does this one now get hot?

Hi guys
Thanks for the replies.

I have previously opened the return valve into a bottle. The water came out at a good pressure (not sure how quick but squirted out quickly).

The rad has never been burning hot since we moved in 5 years ago. I thought it was due to it being old. I think it only got bad last winter. It got coldish. I restricted the flow on some of the other rads in the house and this gave some additional heat but not jumping hot.

There is no extra radiator on the same pipe - the pipes run directly from the 22mm pipe. 4 years ago we did get a big rad in the dining room repiped in 15mm pipe by DP (off of diynot). This comes off the 22mm pipe before the problem rad. However, there was no deterioration on the problem rad at the time he ran the new pipe.

I think the pressure from the valves is good so cannot understand why we are getting a cold rad. Hot water is definately getting to the rad but just doing anything.

If I look at the top of the 22mm manifold pipework we have a 15mm pipe coming off for the dining rad, 8mm for living room rad (the pipework at this rad heats at the same time as the prob rad), 8mm kitchen.

The dining room and kitchen both come out of the side of the manifold pipe, the living room comes right out of the end of the manifold pipe. The problem hall rad pipework comes out of the bottom of the manifold pipe just before the living room pipe at the end - it is the 2nd last pipe furthest away from the boiler.

My thinking was that the return pipe may not be getting to push as easily away from the radiator as it is curving upwards into the manifold pipe and having to compete with all the other return pipes which are coming either from the end or sides. Is this a stupid suggest or a possiblity? If yes, there is a spare outlet on the side that the pipes could be moved to.

I had all rads off except the kitchen and living room (these needed to be open as when I had all locked off except the problem rad, the boiler locked out - assuming because the water did not flow quickly enough away from the boiler). This did not improve anything - the TRV valve was roasting as was the bit of pipe within the rad where the valve goes into but not much heat elsewhere.

Have not tried a chemical clean - would this cause any long term issues with the system - ie is it corrosive?

Thanks again for all replies .
Fluff

There are some powerful acid cleaners that I recommend you avoid. See my jacket that was eaten when a drain cock leaked on it.

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X400 and X800 are mild cleaners, they just loosen the sludge and sediment so it is washed round in the circulating water and can be drained out. X400 in particular will do no harm if you forget to drain it after four weeks, though it will gradually lose its cleaning power and the dirt will settle again.

If you add a system filter, which will cost you about £100, you will be able to watch the sediment being trapped inside it, which is very gratifying, and it will trap future particles so they don't accumulate into a new blockage.

A mild cleaner will do nothing but good, and is an easy first step. Often it will cure the problem, unless you have a pipe which is so thoroughly blocked that water cannot flow through it with the chemical. If you do have to do further work, you will be no worse off, and some at least of the sediment will have been loosened.

Thx JohnD

I will see if I can persuade DH to put some X400 in it - he is reluctant as when we do things, we keep getting leaks. eg tightening the nut on the top of the TRV but not managing to keep a tight grip on the valve so ended up with water leaking from nut around the pipe.

The engineer at my work fitted new valves a few weeks ago but the nut on the top is not tight so we have a slight leak. I turned both valves off and we lost water but it eventually stopped (assuming an air lock or something). Was just leaving until the plumber came back from A/L.

If I put on X400 into the system and open both valves again to the cold rad, I will start to get water leakage again. Will it be ok to catch the leaks in a plastic chinese container or is this stuff corrosive?We don't want to retighten the nut again as we will bend the microbore and this caused us problems before.

This DIY malarky is not fun - it is actually quite stressful - I understand the theory but the practical stuff of getting it done is not easy. Hats off to all the plumbers/engineers.

Sorry, meant to ask - could I just leave the cleaner in for 2 weeks? This would give me time to get plumber in before winter if it doesn't work (I live in chilly Scotland).
Thanks again
Fluff

X400 is not corrosive.

You can leave it in for as long as you like, but four weeks is the optimum.

You should get the leaks fixed soonest. If you add X400, the circulating water will probably go black with loosened sludge and sediment, and this black water will stain floors and especially carpets.

If you close the valves to the cold rad, the chemical cannot circulate through that radiator or its pipes, so cannot clean them.