upstairs radiators hot, but downstairs cold

[rockhallrise]

Tank is filled and ballcock working, I cleaned it out whilst I was there so I didn't drag any more gunk through whilst trying to fix original problem which was cold radiators downstairs but hot upstairs.

I drained a downstairs radiator to see if it was sludgy and the water drained out clear. (all downstairs rads are fed from the ceiling btw). went to check F&E tank at that time, could feel air venting from the overflow that hangs over the top of tank and could feel water sucking into cold water feed. but I disturbed the gunk whist I was fishing about in the tank so cleaned it out. (it was full of soft orange jelly like gunk)

So then went round to bleed upstairs. They would bleed for maybe 20 seconds then stop with no water coming out, closed the bleed waited 30 minutes the could bleed a bit more air, about 5 tries and they are fully blead. (I have a vague memory of it being the same about 10 years ago when we had rads off etc for DIY, so not sure slow bleeding is a new thing)

I thought the original problem of cold downstairs rads, was likely the pump on its last legs, and guessed a lack of pressure might account for the slow bleeding too.

Plumber visited for a quick look, decided it was an air lock, said they were a pain to fix, but said he would fit me a combi boiler for £3000 if I wanted, but didn't offer to fix the airlock, said my boiler had asbestos in and no one would ever fix it anyway.

Tempted to run a hose from one of the downstairs drain points and open it up to see if water runs through and F&E tank keeps up refilling, would that prove anything?

I don't want to go crazy and spend days trying to diagnose stuff for the sake of a £120 pump, but happy to try simple obvious things first. (was curious if the original poster had changed the pump and solved it, seeing as he didn't follow up his last post and it sounded like he was about to try that)

 

[JohnD]

Jelly in F&E tank is bacterial slime. You can temporarily deal with it by emptying out and sponging the tank with bleach. The tank needs to be clean, have a close-fitting lid, and be insulated to prevent it getting too warm in sunny weather. A longer term treatment is Fernox AF10 biocide.

Is your problem "Upstairs radiators won't fill up after draining?"

When did you last use a sediment-cleaning chemical?

 

[rockhallrise]

My problem is actually "upstairs radiators hot, but downstairs cold"

I was just curious if the original poster had fixed his wider problems with a new pump. (Although his original topic was "Upstairs radiators won't fill up after draining?" he tried lots of things and sometimes got his radiators to bleed but they wouldn't all get hot etc. more similar to my problem, than the thread title)

I was starting to contemplate investigations like he describes in the thread but thought rather than spend hours doing likewise I'd be best just start with the pump. Especially if he had done that and fixed his problems.

(Apologies, I know my reply to your reply was a bit scatterbrained, and I wasn't intending to hijack the thread, just find out if he tried the new pump)

 

[rockhallrise]

OK, Just found a very similar thread...

//www.diynot.com/forums/viewtopic.php?t=45459&start=0

Same make of boiler, except I have a different pump and valve*, a grundfos pump and silver box shaped honeywell valve.

(*Just noticed that unlike the other thread my valve may not be a "diverter" as it it not Tee shaped just straight)

The original poster in that thread finished it by saying:

just to close out this thread, had a plumber come around, apparantly the spring return valve is on its way out. After 3 days of no rads he told me that they may come on but it would be sporadic as the valve was sticking now and then.

Low and behold that night the rads come on.... new actuator on the way but at least I have my trust renewed in the honest tradesman!

Thanks for all your help.... thread closed

I guess I should take off the silver cover off the pump and check it is spinning and then is there anything I can do to easily check if the valve might be faulty, there is a small leaver on the bottom of the silver valve cover, will that aid testing in anyway?

Also can anyone explain why a faulty valve might cause this problem so I can understand it, all the downstairs radiators are below the height of the valve would that have something todo with it?

Thanks

 

[JohnD]

My problem is actually "upstairs radiators hot, but downstairs cold"

Have you turned off all the hot ones to see if it is a balancing problem?

I am guessing you have not used a desludging chemical yet.

 

[rockhallrise]

I have not used a de-sludging chemical. (But did drain a bottom rad and was clear water, just slightly grey, even blew in the bleed hole to get every last drop out, just slightly grey).

I have tried switching off all hot rads upstairs, no appreciable difference downstairs, then tried switching off all downstairs as well just leaving one, and did this for each one downstairs. Got very mild heat, but nothing like scorching hot upstairs. The downstairs have got hottish up to the valve but hardly anything in the body of the rad, very slightly warm on the back just above the valve cold on the front.

We have thermostatic valves on all, and even the up stairs seem to take it it turns to heat up for instance one upstairs rad seemed like it wasn't going to heat then 2-3 hrs later it got hot, perhaps after the other rooms had heated and closed their thermostatic valves.