One Radiator not heating up

Kashkai

I turned a radiator off a month ago as we weren't using the room. I turned it back on Saturday night and it heated up but last night, it was stone cold. The inlet pipe is hot but there's no heat in the rad or the outlet pipe.

I haven't bled it or turned the other rads off yet to see if I can heat it up. Before I try this, any opinions as to why this rad, which was working fine before I turned it off, has gone cold?

Thanks

gdavis

valve may be stuck in closed position,are both flow and return valves open?vent the rad too,make sure its full

Kashkai

Thanks but the fact that it did heat up when I opened the valve Saturday night makes me think it's not a stuck valve. Could it have filled with air overnight? When I turned off this rad at the inlet pipe a month ago, I didn't turn off the valve at the return pipe. Could the rad have been sucked dry?

I still can't understand how it did heat up on Saturday though before going cold on Sunday night.

gdavis

sorry i missed that bit!is it thermostatic rad valve?if so,unscrew head and push pin to make sure its moving freely,water wasnt sucked out,have u vented it?

gdavis

if rad is full and flow pipe into rad getting hot then either flow or return rad valve probably the issue.depending on how much of a diy'er you are you could turn rad valves off,crack open the nut on the rad tail piece and drain rad into thick black plastic bag while protecting floor/carpet with couple of old towels,open vent on rad while draining to increase flow,best if u have someone with u doing same at other valve,when its drained,close vent,each of u undo the nuts fully,cover rad hole with finger or plug with tissueand turn rad upside down,carry outside and empty,now crack open each valve into a bag/bucket to see if they r opening.u may need to add inhibitor and open filler loop if there is one when turning back on

Kashkai

Thanks for that. I'm reluctant to lose water out of the system as my filler valve isn't working on this sealed system. The pressure in my system is 0.6 bar when cold rising to 1.3 bar when running. This could be a contributory factor I know but I can't get any more water into the system.

gdavis

can u temporarily connect mains water to system from kitchen sink or outside tap and give it a blast!? u never said if it was a trv on rad,i still reckon its something simple with valve.is ur filler loop off the mains or ur tank,has it an auto fill valve that needs adjusting?

meercat

turn off other rads on your system
this may force hot water into the rad
when your rad heats up,turn the other rads back on

Kashkai

gdavis wrote: »

can u temporarily connect mains water to system from kitchen sink or outside tap and give it a blast!? u never said if it was a trv on rad,i still reckon its something simple with valve.is ur filler loop off the mains or ur tank,has it an auto fill valve that needs adjusting?

The system is sealed and the filler valve is beside my hot water tank and us operated by a small black knob that I've tried numerous times but it doesn't add water to the system
The rads valves are not trv's, just the ordinary valves to open and close the water supply

Thanks for the advice anyways.

gdavis

well u gotta vent rad first and take it from there.if u put up pic of filler loop might be able to help too

Kashkai

gdavis wrote: »

well u gotta vent rad first and take it from there.if u put up pic of filler loop might be able to help too

Il take a pic tonight and post it up. Thanks again

Kashkai

Ok so I tried to bleed the rad but it was full of water. So I stood back and assessed the situation. The inlet pipe was scalding hot but no heat in the rad or return pipe. So I opened up the inlet pipe to max (it was at half way approx) but no joy. So I opened up the return pipe (it was at about a third open) and this worked. The rad started heating up immediately. "Why" is the next question?? Was it an airbubble in the inlet pipe where it joined the rad which was dislodged when I opened the return valve?

Oh, here's the filler valve. Except it doesn't fill of course:rolleyes:

oikster

Probably a build of muck as there was no flow through the rad for a while. The small gap in the rad valve seating would have been easily blocked but not too easily shifted. You should return this valve to near the original setting as this was obviously set there during the initial balancing of the system.

gdavis

yip just bit of dirt in the return needed a shove by opening up return more id say to create circulation,at least u sorted now.is pressure on gauge in pic not at 1 bar on auto fill valve,which incidentally are a pet hate of mine,imo should not be allowed on heating systems,anyway thats another story!they can be adjusted anyway to let more water into system if u need to in future

TPM

gdavis wrote: »

yip just bit of dirt in the return needed a shove by opening up return more id say to create circulation,at least u sorted now.is pressure on gauge in pic not at 1 bar on auto fill valve,which incidentally are a pet hate of mine,imo should not be allowed on heating systems,anyway thats another story!they can be adjusted anyway to let more water into system if u need to in future

I completely agre with you about "auto fill valves"

I thought that the auto fill valve(pressure regulator) was suppose to be disconnected from the supply once the system was filled, and only reconnected if the system needed to be topped up. But through course of habit it seems to now be assumed they are left connected and often turned on to compensate for leaks

Kashkai

The fill valve doesn't work at all. The guage was around the '1' bar mark in that picture because the heating was on at the time and the pressure increases when the water is hot. I left the fill valve open all night and the guage was stuck at 0.6 bar when the system was cold this morning. The system is slowly losing pressure as it was at 1 bar when cold 6 months ago. At this rate, it'll be empty in another 6 months.

TPM

the valve might be "stuck" you could try screw down the adjuster at the top, (usually has a screwdriver slot in it) this will increase the pressure setting, but make sure you screw it back up to its original position as if it overfills the system the safety valve will lift

Kashkai

Thanks but could you clarify where this screw is please and how much should I turn it, ie clockwise or anti clockwise? How will this affect the fill valve?

TPM

Just looking at your picture again, yours appears to have flats on the sides of it, its at the very top of the valve (red arrow in photo).

I would turn it clockwise 1 or 1 1/2 Turns and then turn it back again, if its stuck this should free it.

The "fill valve" is really just a pressure reducing valve, this adjustment is for setting the pressure of the valve output. but the max output pressure is limited to the supply water pressure.

Kashkai

Thanks very much TPM. Appreciate it.

Just for your info, the plumbing in my house is a disaster. The plumber who worked on our build did a bloody awful job. For instance, every rad leaked (I had to take them all off and reseal), the toilets leaked, a seal went under the concrete floor and I had to dig this up and redo the pipework (the push fit he used was damaged and let go spewing water up through the concrete ruining the wooden floor), the showers leaked etc etc. I've had to do a lot of diy plumbing over the past five years:(

TPM

Sorry to hear you have had bad luck with your plumber:(

let us know how you get on with the "fill valve".

Kashkai

No joy on the fill valve. I turned the screw clockwise a turn and a half and waited 10 minutes (with the fill valve open). No budge on the guage. I turned it back to where it was and then tried a turn and a half the other way. Still no luck.

gdavis

if it is off ur mains water i would get rid of it and put in a filler loop with flexi and non return valve and leave diconnected after pressurising