Problem with heating sytem - help please

[chrysagon]

Hi All.

I'm a newbie on this site so if I make stupid statements born out of ignorance please bear with me, I'm not a plumber but an enthusiastic amateur and DIYer.
My CH system is approx 28 years old and consists of an Ideal Mexico Super(RS40) with initially 7 radiators(fitted with Sopac TRV's), 4 upstairs and 3 downstairs. A number of years ago an eighth small radiator was added in the kitchen about 4 feet from the boiler. the system has been fine apart from the boiler thermocouple changed a couple of times and the pump (grundfos UPS15 Type A )changed once. A few months ago the kitchen radiator started to lose heat and eventually went cold. I tried bleeding it but this made no difference. I didn't bother too much about this as it was in the kitchen which is usually warm anyway, however the hall radiator started to go the same way and eventually went cold then the main bedroom radiator went the same way. I should say that I put some X300 through the system about 6-7 years ago but didn't put inhibitor in after (oops)
Anyway, all this week I've been trying to get all radiators running again and am at the stage of removing what hair I have left. Here's what I've done so far.
Took the hall radiator off, flushed it and refitted.
Drained system and put X400 in and ran it again - this hasn't made much difference.
Flushed out bathroom radiator

I now have a situation where 3 radiators upstairs work but the bathroom one, which is nearest the manifold, doesn't and the downstairs radiators dont work at all. Thinking perhaps the pump was gunked up, I removed and cleaned it and there was a piece of plastic stuck in one of the impeller chambers and the impeller itself was pretty gunked up. I thought I had cracked it and all would be good, not so, still the same.
I can't think what to do next. Is it possible the pump is bad even though it runs fine with very little noise/vibration and all 3 speeds work. It seems like it still isn't pumping hard enough for the whole system but how do you check this. BTW the water isnt heating up much now in the hot water tank since cleaning the pump even though pipe going into tank is hot.
Any suggestions/help gladly appreciated

Thanks,
Chas

 

[expat]

Sounds like gunk/sludge is the problem causing a little blockage here and there mounting up to no circulation.Everything needs a good flush boiler,rads pipes simple enough to do with a hosepipe

 

[newbie1]

if its gunk you will never clear it with a hosepipe..it needs a powerflush

 

[chrysagon]

Thanks for the info guys.
I put Sentinel X400 in the system a couple of days ago, wont this clear out anything in it ? Also, I'm a bit concerned about power flushing due to the age of the system. Might powerflushing cause leaks ?

Cheers
Chas

 

[doitmyself]

I put Sentinel X400 in the system a couple of days ago, wont this clear out anything in it ?

Let it circulate for four weeks before you drain down.

Also, I'm a bit concerned about power flushing due to the age of the system. Might powerflushing cause leaks ?

It might if there a leaks which are being blocked by sludge. In any case, there is no guarantee that a power flush will remove all the debris.

 

[HTB]

Its also worth checking the pump isn't now airlocked. Might also be worth balancing the system, turning down the locksheilds on the upstairs rads a bit to give some more priority to downstairs.

 

[stevetheplumber]

id be tempted to change the pump first as yhey often seem to be running fine but actuallly doing very little pumping
if powerflushing seems a little harsh for your mature system you can do what we did before powertfl,ushing became the new holy grail
take each rad in to the garded and attach the garden hose you can then jugle hoses onto valve to flush the pipework
but id try the pump first