Non Working Radiators

[hammerman]

Got 2 upstairs radiators that don't work. The system is certainly 30 years old but most of it, including the boiler and pump have been replaced recently.

What's the best way to check the 2 upstairs rads ? Could they be bunged up with crud ? they have an old thermostatic valve on, could that of seized shut ?

Got no problems with removing and flushing the rads through but what if the pipework is gunged up too ?

any suggestions welcome

[Togo]

Bleed the rads Make sure the stats are asking for circulation( temp. setting)
With the heating on check which pipes are getting hot. It could be a pipe blockage or the rads may need the system draining down and flushing through.

[Togo]

Hammer you bleed the rads with the little key. If they are full of air the water will not circulate. This is possible system has been worked on. Also ensere that water is able to enter the system from the expansion header tank

[retrocop]

I believe Fernox do quite a strong crud remover.Stronger than the usual inhibitor.It is pumped throught the system.Apparently it will find weak joints as well which could be a problem.You could have the pipework pressure tested but that involves specialist kit.

[The Builder]

Another possibility, Hammers ................. if those are the only radiators upstairs, then it could be a pump circulation problem.

Downstairs rads often still work but under gravity only.

[KARL]

Yet another suggestion:

After venting any air from the system have the heating on (24 hours on any timer, electricity on, boiler on, boiler thermostat up past mid-range, etc.), any room thermostat turned to max, and all radiators but one turned off. Trace heating up of pipes as accessibility allows and then expect the one radiator to warm up. Don't be impatient, circulation may be poor but if the radiator does not heat up within half an hour there is likely to be some fundamental (but not insoluble) problem with the system. Repeat with the other radiator, then finally try both radiators with the rest still turned off.

All the above assumes that the rest of the system heats up satisfactorily and there is not a separate zone valve for the radiators in question and that the boiler and pump work during the above test.

If both radiators warm up satisfactorily during the test (and the others normally do also) but still won't when the others are on then it is likely that you need to re-balance the system.

The procedure could be as follows: Assuming there are downstream (outlet) valves on the upstairs radiators, then open these completely and, with the whole of the system operating (all radiators on full) and everything warmed up, close these outlet valves down gently step by step over a good bit of time until you find the radiator(s) are no longer as warm as they were before. This is the first step - refine (open or close each one) as you feel necessary on the same principle. What you are aiming for is for the water flow to have equal resistance on its way to each and every radiator in the house, giving every one of them an equal chance at getting hot.

Are you new to this system, is it possible the previous users simply did not believe in warmth for these radiators/room(s) and thus the radiators are actually turned off on the outlet side to ensure cold conditions (possibly leading to sedimentation in lines if you have now opened the valves up) ?

[alavahalf]

My thought is keep it simple before getting too involved .. if these two rads have been shut down (as in winding the thermostats down) since last winter.
They may well be stuck in the closed position, even if you have released the flow by unscrewing the trv head.
The first thing I would do is place the head of a hammer behind the body of the valve and then strike the opposite side of the body with the handle of a screwdriver or something solid. This often breaks the seal that has been created with the trv having been closed for a few months over the spring and summer.

[hammerman]

Thank you all for your answers. My pal is a plumber (but i hate asking him for help) popped round. We fired it all up, whacked the thermostatic valves a bit and moved the pin and after shutting all the other rads down, and a lot more whacking, the pressure finally got through and we now have a full set of working rads....and a happy hammer :-)

Again, thank you all for your help