No Heat in radiators

[haggishead]

1st problem - downstairs rad's cold. Thought I'd try fernox restorer.
Drained system all ok - put 1 ltr of fernox in header tank - filled again - still no heating downstairs. Hot water boiling. Left for a couple of weeks..Try again... Drain system opened upstairs bleed valves watched bucket's fill with black water, then opened downstairs kitchen rad .. no air, just lots of water ?, which eventually stopped. Then opened all other downstairs rads only air at bleed valves . Shut all bleed valves/drain cock, refill system - bled all rads (downstairs 1st ) - now all rad's cold !!.
Pump's working ok. The top feed into the cylinder is very warm ( from pump )- bottom cooler. Across the cylinder's side conn's is a valve with a thermostat attached to cylinder , the o/p from this valve is very warm. So I have two very warm o/p's from the valve and one cooler one coming from the cylinder coil. Does anyone make see through pipes ? Can anyone help please.

 

[scaby]

the last bit of your post is a little unclear, what type of valve do you have?is it a tee or two seperate valves,you should find it/them between the pump and cylinder

 

[haggishead]

Hi scaby, The device across the cylinder is a 3 port ravi danflos thermostatic valve, a thermocouple is attached to the cylinder side. The top cylinder pipe goes to A; the bottom cylinder pipe goes to B and the o/p is marked AB.

 

[scaby]

no that a hot water blending valve,there should be another valve/s somewhere near your hot water cylinder,although it could be anywhere,when you find it post back

 

[haggishead]

Scaby, Nightshift, hence the delay...In the cylinder cupboard I have 5 valves in total. (1&2)Two valves either side of the pump.(3) One valve on the pipe coming from the cold water tank ( big one);(4) One valve going across the cold water tank pipe & cold water tank vent ( this is only a 1/4 turn); and finally(5) one valve after the blending valve , which goes to a T ( one end going downstairs and then splits into 2 pipes) and the other end goes to the o/p from the FE tank ( small one ).
The vent pipe from the FE splits into 2 one end to the pump and one end goes downstairs. The flow direction on the pump has the arrow pointing downwards towards a T piece - one end splits in two and goes downstairs the other end goes to the upper side conn on the cylinder & top side of the blending valve.

 

[haggishead]

Scaby,latest update...Getting cocky now..In desperation, closed the 1/4 turn valve btwn cold water tank ( big tank) & cold water tank (big one) vent.
Now getting 3 out of 4 rad's working upstairs. 4th rad not warming up nor are the pipes at the bottom of the rad

 

[haggishead]

Scaby, 2nd update. 4th rad upstairs now heated - very warm at lh pipe,just warm at rhs pipe. 3 downstairs rad's cold. Rgds

 

[scaby]

jesus your system is getting on a bit, it sounds like a circulation problem,close all the valves on the upstair rads and force the water down stairs, if that doesnt work change the pump

 

[haggishead]

Scaby, Thanks for the help. I'll try out your suggestions tomorrow, after my night shift - although the pump was changed less than 2 years ago -( Pegler TC 6 - from Screwfix ). Is there a more powerful pump on the market ?

 

[scaby]

a 6 metre head pump will be adequate, first check pump is running,you should feel a soft vibration and hear if its running,what number is the selector on? make sure its on three when you close the off the upstairs rads