System Config Information and Cold Rads

Hi all, Have recently moved into a an old farm house and am trying to get the the cental heating working in all rooms. It's dam cold up hear in Scotland.
Basic problem is that 2 rads downstairs and two rads upstairs will not get hot. This leads me to my first system config question. There is a Thermostatically controlled rad in the kitchen next to the boiler (Boulter Camray Model 70/90 fitted 1991) The rad is fed from what looks like an auxiliary cct directly from the boiler, it does not seen to be supplied by the pump since the main outlet pipe goes directly to the pump in the kitchen attic. This rad gets slightly warm at the top (fed from the top) the rest of it is cold. Rad has been removed and flushed. There seems to be pressure when one or other of the taps is open but no flow when both are open. This is a sealed system pressurised at 1.5 bar by main supply to a pressure vessle. Does anybody know the reason for this auxilluary cct setup? Rad has been bled to no avail.

The 2 rads up stairs that refuse to get hot are doing my head in. Hot water getting to both rads if I close the outlet valves, open the inlet thermostats and bleed. If I close inlets and open outlets there is back pressure present when I bleed (Pump looks to push water to the inlets rather than pull the outlet). Open both valves, both rads an stone cold, no flow at all. I shut all other rads down except these two, closed the hot water loop and cranked up the pump to try and shift any airlocks. As you may have guessed, to no avail . The 4th rad down stairs is having the same problem. I have run out of ideas. Any further suggestion Final question is this; Just after the pump there is a 15mm pipe leading straight to the return to the boiler with a stop tap in line. Where should this tap be set for the normal operation of the system?

Thanks for your help, and hopefully, with your help I will start to feel my toes again!
Regards
Dave

I found that quite difficult reading which is probably why no one has answered up to now. Certain parts are a little vague because I cant see the job but I will have a go to get you started.

The first paragraph seems to relate to either a gravity circuit fitted in accordance with the boiler instructions or perhaps a heat sink which is a relic from a pre existing solid fuel boiler or aga. I'm not familiar with most boulter products being a townie.

The problems you seem to be having next would have me checking out the efficacy of the pump. It could be spinning but theres no saying that the impeller is attached to the armature. Are the valves fully open?
Also an airlock or sludge problem or perhaps some incorrectly installed pipework could be the cause of your troubles

Lastly the pipe with a valve that you refer to is almost without doubt a by-pass valve.
Closing this valve will procure maximum circulation from the pump around the circuit so close it for now till you get the rads working. When you have cleared any airlocks it should be left slightly open so that there is a temp difference in the flow and return to the boiler normally of 11ºC, but officially whatever temp is prescribed by the boiler manufacturer.

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quote="Slugbabydotcom"]I found that quite difficult reading which is probably why no one has answered up to now. Certain parts are a little vague because I cant see the job but I will have a go to get you started.

The first paragraph seems to relate to either a gravity circuit fitted in accordance with the boiler instructions or perhaps a heat sink which is a relic from a pre existing solid fuel boiler or aga. I'm not familiar with most boulter products being a townie.

The problems you seem to be having next would have me checking out the efficacy of the pump. It could be spinning but theres no saying that the impeller is attached to the armature. Are the valves fully open?
Also an airlock or sludge problem or perhaps some incorrectly installed pipework could be the cause of your troubles

Click to expand...

Bravo , Sir Slug, it was a mighty task & someone had to do it, not that you are are right but you are a brave man to have prolonged with this Epic. I`m going for a lie down.....

Where these rads that are not working all gravity fed for summer time operation, ie when pump not running. To take the chill off in kitchen and say bathroom towel radiator/bedroom upstairs.

These canny Scots wouldn't want to pay for a pump to be running when they don't need to.

Also, guessing further, is there a zone valve you haven't found or was there a wood burning stove or aga installed prior to boiler, not much help I know, but anything better than nothing.

You may have a mixture of both gravity and pump!

Where these rads that are not working all gravity fed for summer time operation, ie when pump not running. To take the chill off in kitchen and say bathroom towel radiator/bedroom upstairs.

These canny Scots wouldn't want to pay for a pump to be running when they don't need to.

Also, guessing further, is there a zone valve you haven't found or was there a wood burning stove or aga installed prior to boiler, not much help I know, but anything better than nothing.

You may have a mixture of both gravity and pump!

Thanks Guys, You may well be right about the gravity feed to the single rad in the kitchen being a relic from an old Aga since there was one installed some years ago and then removed by some philistine! All the others are on the pumped cct.

However, The problem is solved... The pin Valve acted on by the danfoss thermostat was the culprite in all cases of cold rads. Took the thermostat head off with the aid of an allan key and exercised the valve gently with a pair of pliers. Success ! Thanks again all for your help and info.
Regards
Dave