Is filling the expansion tank with water a short term fix?!

During the recent sub zero conditions, my radiators has decided to give up on me, and I would like some advice on a long term fix..

A few weeks ago, one of my radiators decided not to work properly, where the top half is cooler then the bottom. I tried to bleed the radiator, but I bled it to the point where there were no more air coming out.

A few days later, all but one radiator on the second floor, decided not to work anymore. And again, I tried to bleed them all, but again, none of them had any air in them to come out.

I have been told that the pipes going to the feed and expansion tank is full of sludge. To fix, I need to have a garden hose, which at one end plug into the garden tap, the other into a strange looking tap (located inside my garage). I turn the garden tap on, which will fill the water into the expansion tank, then bleed all the radiators. This is what I did today, and it worked! But after 10 hours, the radiators are starting to cool down again, therefore I would need to redo this hose business in the morning.

The question is, if I continue to do this regularly, would the problem eventually go away?! or is this just a short term fix and I would need to get a plumber to come in to rework on the pipes?! I wouldnt want to blast water into the expansion tank everyday to keep it running properly!

Many thanks, I look forward to your reply
Neil

Usually a blockage from the F&E tank is a VERY solid blockage at the point where the 15 mm joins the 22 mm flow pipe.

In most cases the only solution is to cut the pipe and either try to clean it and replace or to fit new pipe using compression connections to make the job easier in case it needs opening again!

Tony

If the water is going out of the expansion tank and into the system then it cant be blocked solid with debris.
Might I suggest
1 connecting a temporary mains cold water supply to the vent for the purpose of blasting any partial blockage back through to the exp tank
2. Checking pump function
3. Check that pipes are adequately lagged
4. Fitting a magnaclean and or a powerflush
5. Check boiler stat function.

oki i decided on my infinte wisdom to go and fit a new radiator for my mate.
Id plugged the cold feed and vent with bungs and fitted rad and new pipe work fitted some fullflow boiler fixes on the drop out of sight. All great 3 pm looking like a early day....just fill up.

pull the bungs and go to fill rads. not much air coming up.. thats odd.
I conclude that both the cold feed and vent are frozen. The header tank is in a bitch of an ashlin in a diy loft conversion. i attempt to blow down the vent to no avail. The new rad has just made the situation worse as the water had dropped down from the upstairs circuit. I attach a hose to the draincock with a jubilee clip and make sure the outside (larger) nut is tight undo the drain off center and get another person to open the outside tap pressurising the system, vent the aircocks. In my case the pump managed to clear the vent. But the assumptionis the cold feed is still frozen.

You must have a major leak somewhere, As when the system is full it shouldnt need rehosing at all. The air isn't coming out as there isn't any water in your system. many leaking systems are put in and are never highlighted until the cold feed stops filling the system.

Ok I just had another look at your topic.

To fix, I need to have a garden hose, which at one end plug into the garden tap, the other into a strange looking tap (located inside my garage).

Click to expand...

What you are doing is backfilling the system through a drain off valve. Which is not the way I misread it early this morning. I'll stick by the suggestions I made earlier especially points 1 and 3 but now concur with Tony that your feed pipe may be solidly blocked and also with the point made by MrBenchmark that you may have a leak somewhere. Another point I would like to add is that sometimes a faling pump will suck air into a system. In my experience Grundfos seem to be the most common culprit for it, By taking the head off a confirmation can be made if the inlet is black in colour and the outlet is rusty red denoting the ingress of air.

The way you are currently filling your system you willl need to temporarily cap off the vent to stand a chance of blowing out any blocked feed pipe. Remember that at any time your drain off valve due to its design may just decide to act as a non return valve preventing you from filling your system at all.

One one occasion I have successfully fitted a bypass - a secondary F + E pipe as a solution, as there was no access to the pipes feeding a back boiler. Of course one must carefully consider where one is connecting to in the layout of the system...

First of all, thank you to everyone who has replied me.. I fully appreciate the time and effort of every poster here that has given advice to me, a total novice when it comes to DIY.

Secondly, I have to apologise for replying so late, but I have no clue about these sort of things, therefore I had to do my own research and see if I can do the work myself. If its too complicated, I would have to get a plumber instead, as he did mention last time, the problem is in the pipes, and it would cost £200+ to get him to clear it out. I was hoping that using this method (filling the expansion tank), can save me asking the guy to come back again, as its something I can work with.

I also wanted to see if all the radiators will work if I fill the expansion tank enough times. For the last 20 days, I must have nipped into the garage four or five times. I have found everytime I did it, the radiator is much hotter then the previous time filling the expansion tank. I had five radiators which had this problem, and now I have three of them which are hot constantly, which I dont need to bleed them (Hope I didnt jinxed it now).

Im hoping the other two radiators will come together as well, which will save a lot of hassle. As its coming to February, this should be the last cold month (again hope didnt jinxed it), so we dont need the radiators for a few months.

Again, thank you to you all, i will let you know if all radiators are firing up!

Neil