Heating working upstairs but NOT downstairs Baxi Bermuda back boiler

[IrishThai]

Hi New to forum,have replaced 80% of the plumbing system in the house over the last year it's a 3 bedroom with big single storey extension on side , fully working Baxi Bermuda back boiler )old but working well so no I won't replace till it goes,9 radiators, 1 bathroom , 1 downstairs shower basin and WC.New Hot water tank , pump , motor valve, all radiators (3) in extension replaced as well as all pipework, all rads removed & flushed in extising house system pressure tested using air comp to 6 bar and no leaks system then wet checked and working for 4 months no leaks or problems loads of hot water and all rads heat up fine and too hot too touch.
All working fine till flushed system out prior to putting corrosion inhibitor and now the downstairs does not heat up. have bled all the rads, water flows freely and is clean.tried to bleed system by open the drain valves at each end of the system till hot water flows which does occur but once valves shut the rads dont heat up.Confused.com is an understatement.
have read many posts and heeded replies saying what is fitted etc etc

 

[stevetheplumber]

Hi New to forum,have replaced 80% of the plumbing system in the house over the last year it's a 3 bedroom with big single storey extension on side , fully working Baxi Bermuda back boiler )old but working well so no I won't replace till it goes,9 radiators, 1 bathroom , 1 downstairs shower basin and WC.New Hot water tank , pump , motor valve, all radiators (3) in extension replaced as well as all pipework, all rads removed & flushed in extising house system pressure tested using air comp to 6 bar and no leaks system then wet checked and working for 4 months no leaks or problems loads of hot water and all rads heat up fine and too hot too touch.
All working fine till flushed system out prior to putting corrosion inhibitor and now the downstairs does not heat up. have bled all the rads, water flows freely and is clean.tried to bleed system by open the drain valves at each end of the system till hot water flows which does occur but once valves shut the rads dont heat up.Confused.com is an understatement.
have read many posts and heeded replies saying what is fitted etc etc

pump isnt working classics symptoms especialy after works been done

 

[so-solar]

as above!!!!! Typical pump symptons

symptoms

 

[IrishThai]

will check tomorrow but 99% sure pump works as it makes a pumping sound and the speed control works i.e varies the sound pump was new a year ago grunfoss type
cheers for the quick info though

 

[david williams]

pump motor may be active ,impeller jammed,these are circulators not pumps ,and are not shaft driven,so motor may be making sounds but is not driving impeller

 

[stevetheplumber]

will check tomorrow but 99% sure pump works as it makes a pumping sound and the speed control works i.e varies the sound pump was new a year ago grunfoss type
cheers for the quick info though

if the pump feels realy hot this is a sign its not working ive seen grunfoss pumps actually change colour from overheating and yes they do sound like there working

 

[IrishThai]

Hi Guys , have checked pump, the impellor rotates easily in both directions and checked pump body temp with Raytek laser thermometer 70 degrees C
compared with surrounding pipework 55C above and 49C below plus get the sound of water being pumped around system as well on the top speed lower speeds hard to tell.
Motorised valve appears to work fine as well
one thing I did notice that with the removable cap out of the pump the impellor does move in and out maybe 1 or 2mm
is this free play taken up by the cone shaped inset in the cap?
still confused.com
and if it is the pump? is there a better make than Grundfos the previous Grundfos had been in there since about 1988 bearing in mind this last one has laster only 18 months (found reciept)
cheers again for help so far!

 

[david williams]

when pump on remove screw from face of pump and check spindle rotates,use a pencil if working you will feel it rotate,

 

[REDSAW]

.
All working fine till flushed system out prior to putting corrosion inhibitor and now the downstairs does not heat up. have bled all the rads, water flows freely and is clean.tried to bleed system by open the drain valves at each end of the system till hot water flows which does occur but once valves shut the rads dont heat up.

sounds to me the lockshields are bunged up if the rads heat up with the bleed screw out allowing circullation.
what happens when you turn of all upstairs rads then?.

 

[IrishThai]

when pump on remove screw from face of pump and check spindle rotates,use a pencil if working you will feel it rotate,

Pump spindle rotates fine and is smooth and feels like it should i.e a bit of resistance so pretty certain it isn't sheared but the spindle does move back and forth though and know from being a motor mechanic that car water pumps don't do this hence the posted question on the movement
Any thoughts?
Shut of all the upstairs rads and the downstairs hallway rad supply pipe do get hot 45C and the rad did heat up but none of the others did
valves should not be blocked as reverse flushed it and was working fine till I did this
motorised was checked and moves when told by control unit

 

[david williams]

if all electricals working properly ,your left with sludge blocking somewhere