central heating only partially working

[westy]

We have an ideal Classic boiler serving 11 radiators. Noticed last week that one downstairs radiator was not on at all despite thermostat at 6. This rad had previously been at bit cooler. Checked thermostat and it did not seem to be working so drained system and replaced thermostat. Then none of the downstairs rads would come on. Spoke to a plumbe r who gave several suggestions, all downstairs rads came on after switching off all upstairs rads so it was assumed to be the pump. Replaced this with a Grundfos 15 - 60 still no better. Now intermittant noise from pump have bled rads several times. plumber came and had a look and said to try changing 3 way valve, done this but still have same problem with only some rads on and noise in airing cupboard. This has been going on for over a week now and is driving us mad.
Any suggestions please

 

[kevplumb]

lock the valve on man when you fill the system

 

[westy]

Have already tried that
thanks

 

[kevplumb]

what speed is the pump on ?

 

[westy]

I have tried it on all 3 settings

 

[kevplumb]

not trying to insult you is there a bleed in the airing cupboard on the h/w side you might have missed

 

[westy]

Have done so already. only one bleed in airing cupboard and have bled this several times. Have removed all lagging to check that there isnt another and cant find one

 

[kevplumb]

bear with me marra im looking at a screen
try turning the rads that are working off
you have air in the system somewhere

 

[westy]

have done this before and downstairs ones worked except original one with problem, although this one did heat up when upstairs turned off prior to new pump. trying it again now
have been bleeding all rads like mad but to no avail, any tips on finding the air lock?
Is it worth connecting a hose and flushing whole system through? I forgot to mention that the house is 7 years old and has microbore pipes if this has any bearing.

 

[kevplumb]

could well be cr*p in the manifold / s

 

[westy]

By manifolds do you mean the lower entry points of the radiators?

 

[kevplumb]

the bits where one big pipe goes into loads of little pipes
usually on the landing

 

[Leezygeezer]

I am assuming that the bleed valve in the cylinder cupboard is after the 3 port valve and on the primary cylinder flow circuit?

Might be better to re balance the entire system bleeding each radiator in turn as you go as well as the valve in the cylinder cupboard.

 

[Biguns]

Could be my eyes, but can not see any mention of new pump being bled ?

 

[East Kent Coastal]

Could be my eyes but this thread is 5 and a half years old...