rad not working- help

johney

hello Folks,

never worked right really. Only upstairs rad. All downstairs one's ok. Turned the cylinder valve to heating only and
turned off all other rads, leaving just problem rad on, but still the same. Pump on setting 3. Only heating very bottom of rad. Flow an return valves open and hot.
When I open the bleed valve first time a little air came out and then nothing. No air, no water. Now nothing comes out.
Any help appreciated.

Hal1

You need to bleed all the rads. Do downstairs first then upstairs.

Wearb

Hal1 wrote: »

You need to bleed all the rads. Do downstairs first then upstairs.

Probably not.
Symptoms are typical of a lack of pressure in pressurised heating system.

You need to top up the pressure. There has been a few recent threads here explaining this procedure.

johney

thanks for quick reply lads,

other rads were already bled. Had a little air but none now.
System is not a pressurised system. Its open vent with a header tank.

Wearb

johney wrote: »

thanks for quick reply lads,

other rads were already bled. Had a little air but none now.
System is not a pressurised system. Its open vent with a header tank.

Then you should be getting water out of the bleed. How high is the tank above that rad? One circ pump? Other working rads upstairs? Did you try bleeding it with heating off?
You may need to remove that rad and check it and the flow at both valves.

johney

only 1 rad upstairs. all downstairs rads ok.Cylinder on ground floor 3 feet off ground. Header tank in attic about 2 feet above upstairs rad and 5 metres away from it. Half attic is the bedroom with the rad, hence the 2 foot.Tried bleeding with heating off, no joy. Just 1 circulating pump. It's a small little dormer with only 7 rads in total.

denismc

I had a similar problem recently, turned out the radiator valves had become completley blocked with crud. Our water comes from a well and can be quite silty at times so it looks this added to all the crap in the hot water system.

You can get a plumber to do a power flush of your heating system for a couple hundred euro, it should improve the heat coming from the system.
Alternatively you can remove the rads and flush them with a hose, this can get messy if your not careful.

Wearb

johney wrote: »

only 1 rad upstairs. all downstairs rads ok.Cylinder on ground floor 3 feet off ground. Header tank in attic about 2 feet above upstairs rad and 5 metres away from it. Half attic is the bedroom with the rad, hence the 2 foot.Tried bleeding with heating off, no joy. Just 1 circulating pump. It's a small little dormer with only 7 rads in total.

If the bottom of the expansion tank is 2' above the top of the rad, then you should be getting water out of it's bleed screw. It may take a while.
Any rise and then drop and rise again on rad pipework?
Always bleed with circ. pump off.

johney

thanks lads,

the upstairs rad pipes are qualpex and they travel up to ceiling height, then through the ceiling joists for about 3 metres, then take an easy curved 90 degree turn and travel along a joist to to far side of the room, about 5 metres away,then up a few inches inside the timber framed wall. From there is a 90 degree fitting so the pipes come straight out from the wall to the rad. Looking back now it does seam very long and convoluted. Now where the pipe travelled along the joist, I cannot be sure if he allowed a dip of any kind to occur. I remember most everything about the job but I was not watching out for this and did not know it would be an issue. It was a long run of qualpex and there could very well be an easy downward lag on the pipe.
Thing is, it was done this summer and I was there when plumber did it. He went abroad a week ago and will not be back till end of Jan.He told me before he left he can have a look at it when he returns. In the meantime my 2 boys are freezing in this room, so I will do what I can to fix the issue or at least eliminate what its not.
Measured it and bottom of exp tank is only 1 foot above top of rad. All downstairs have short pipe runs compared to this one, but as I said, even with all the others closed the rad is still the same. No air, no water. Its all newly plumbed with new rads so there should not, in theory, be any crud in the system. At first firing it took a long rime to get all the air out but now its back to square 1 again. If it worked once it should again right?
Could any of the above be an issue?
anyway lads thanks for all your help and interest.

Wearb

With such a small head of water, it's going to be difficult to clear airlock.
Maybe you can rig some sort of syphon from bleed screw to clear it.

Long term: sealed system or maybe see if you can rise expansion tank.

DublinDilbert

As other days have said you should be getting water out of the bleed screw.

The other thing is only one pipe might be air locked. Close one valve try bleed, then open it and close the other and bleed. I've had this before due to one pipe taking a more complex route. The rad was full of water but the longer pipe wasn't. Shut off both valves, disconnected rad, drained into bowl. The opened up each valve till the water came out. Refitted rad, not a bother since.