no heat to cast iron radiator

[maddfridge]

hi everyone

we have a site where i work that has old calorfiers and is a pumped system on 1 insh metal pipe work and despite numerous drain downs and the like we get the following.

heat flows through great for about 20 minutes then goes cold quite quickly

rads on the other side of the circuit work fine

we have tried many methods including back filling form a hose and a pump from the calorifer to no avail ??????????

has been flushed though as well both the calofier both in feed and outlet

any ideas appreicated

 

[justlead1]

Assuming there is no air in it? Why not turn all the other rads of and see what happens.

 

[markproperjob]

THATS GOOD ADVICE FROM JUSTLEAD.
I have had sooo many airlocks in large systems, and the only way ive cured them is to connect a hose to a high level radiator near a wc, (i keep a few rad valve stub tail fittings, close off rad valves to a bathroom rad, vent any pressure with key, unscrew top bleed screw cap, screw in stub tail, fit hose to this, put other end down wc under water, open ONE rad valve, let crappy water flow down wc and wait for GLUG GLUG as air is vented forcibly, then close valve, and do same to the other valve.
if this doesnt clear all the air, close off every other rad in the property and do it again.
this is like bleeding car brakes, keep the hose under water to stop air ingress.
it will ALWAYS shift even stubborn airlocks!
mark

 

[maddfridge]

hi there all

finally got some heat into the radiator today following substainal bleeding and back flushing session hose on the drain and a hose on the flow. push and pull got it all out. rust sludge a little like a costa coffee on draft lol

sorted it alll out thanks for the advice

cheers

pm

 

[markproperjob]

Ha ha!
2 sugars in mine!
Glad u fixed it.

 

[markproperjob]

Ha ha!
2 sugars in mine!
Glad u fixed it.