Cold Rad.

nosmo-king

Its nearly that time again.
I have one radiator (last on line) which doesnt really heat up. I read somewhere that if the return flow is not good the result will be a cold rad. The inlet side (pipe ) gets really hot but the outlet is only warm. Without taking up floor boards can I work out if the pipe is blocked or partly blocked along the line. How can I get this rad to heat up fully. The rad itself is clear.

Any ideas

ircoha

Op: what u mean by The rad itself is clear.

is the rad full/part full of air: how much of the rad is actually hot/warm starting from the bottom.

Can u access the pump and see if it is set to max speed?

How old is the system?

Is this a new problem?
From what u say it sound like a single pipe system and perhaps the pump is not strong enough: if u turn off a few of the earlier ones on the circuit what happens: if it heats then u dont have a blockage?

mukki

okay inlet gets hot thats fine, and outlet is only warm so thats good too, shows the water is loosing heat in the radiator and hence warming the room.


unless
1) there is massive heat loss elsewhere in the room

2)flow to or from the rad is restricted so only a small volume of hot water is entering it...
this could be due to a loss of pressure from the pump to the rest of the rads- make sure both taps on the cold rad are fully open, if that doens't help close one tap on all other rads about 90% to see if that helps, also try changing the speed setting on the pump

3) the lines might be blocked with sludge,

i'm no plumber but i though of this last year and when i treid it it did a great job, still working better then ever....
1)close the 2 taps on ever rad in the house
2)remove one of the rads, and connect a hose pipe to its water supply,
3)feed hose outside or into a sink, open the rad tap and turn on your heating
4)wait till the water running from the pipe is clear
5) open the 2 taps on one of your rads
6)wait about 20mins for the water to clear again
7)then close the 2 taps and go on to the next rad
8)keep going until you got sparkling fresh water in all your rads
9) remove pipe and reinstall the rad you removed but keep the taps closed
10) using a syringe put about 3/4 of a bottle of that rust inhibitor (chadwicks in navan have it) into the empty rads bleed screw hole
11) open the 2 taps on the rad, only let some of the air out of the rad to avoid loosing the inhibitor
12) turn on heating to move inhibitor around for an hour
13) turn off heating, and let rads cool, bleed the rad you removed
12) run upstairs and empty the inhibitor bottle into the rads top up tank