Upstairs rads hot, downstairs not

Stephen P

Our expansion vessel in the hotpress developed a leak and we replaced it today. Now the upstairs rads are hot and downstairs cold. If I turn off the upstairs rads the downstairs ones come on. It's gas central heating.

Any advice on what's going on?

youtheman

Assuming you don't have zone valves, it sounds like a balancing problem. The hot water wants to take the easiest route around the system, which appears to be upstairs.  It's hard to see how the system could become totally unbalanced by a single job being completed in the hotpress.  I suspect the balance valve on the hot water cylinder coil was left fully open.  Maybe wind it in a bit to see if it forces the water through the radiators downstairs.

Stephen P

youtheman wrote: »

Assuming you don't have zone valves, it sounds like a balancing problem. The hot water wants to take the easiest route around the system, which appears to be upstairs.  It's hard to see how the system could become totally unbalanced by a single job being completed in the hotpress.  I suspect the balance valve on the hot water cylinder coil was left fully open.  Maybe wind it in a bit to see if it forces the water through the radiators downstairs.

I had my dad out this morning and it seems to be working now. There was some air still in the expansion tank and he bled all the rads again. Fingers crossed it's working 100%.

whiskeyman

I may have similar prob.
Had upstairs working and downstairs not.
Now nothing seems to be working. Had similar problems a couple of weeks ago and playing with valves on rads seemed to work then, but it's not working now.

Gas, with no zonal also.
Boiler seems fine as we've hot water, and motor appears to be working.
I've tried bleeding all rads and adjusting both valves on rads, but now nothing working

There's an expansion tank in the hot press beside the main cylinder, but not sure how to tell if air in it or not?
Any suggestions welcome as we're freezing!

youtheman

The expansion tank is there just to maintain pressure in the system.  Should make no difference to how the heat is generated or distributed.  So if you look at your pressure gauge on the boiler and if it is normal then you can definitely rule that out.
Your problem also sounds like a balancing problem.  If you've messed with both valves on each radiator then you might have completely unbalanced the system.  Suggest you close in all radiators (bar one or two) and see if they heat up.  If they do then this will rule out a boiler problem and/or an airlock problem.

whiskeyman

youtheman wrote: »

The expansion tank is there just to maintain pressure in the system.  Should make no difference to how the heat is generated or distributed.  So if you look at your pressure gauge on the boiler and if it is normal then you can definitely rule that out.
Your problem also sounds like a balancing problem.  If you've messed with both valves on each radiator then you might have completely unbalanced the system.  Suggest you close in all radiators (bar one or two) and see if they heat up.  If they do then this will rule out a boiler problem and/or an airlock problem.

Thanks so much for the reply.
The boiler itself is a very old Elan 2 model and doesn't appear to have a pressure gauge.

Pretty sure I tried closing all rads and opening just one but no luck there either.... so am thinking perhaps airlock?

I also can't seem to find the water supply tank for the heating system. This isn't the hot water tank in the hot press, is it?
Many articles online say checking this tank first to ensure water in it / in case it needs to be topped up.
Only the large water tank in attic also.

youtheman

Just to clarify.  If it is a 'closed' or pressurised system then you have a (typically) red vessel, but NO expansion tank in the attic.  So you're not relying on the header tank to maintain the pressure, you pressurise it up and the red vessel is an accumulator to keep it pressurised.  On the other hand if you have a small header tank in the attic then it's an open system, so there will be no pressure gauge in the system.

whiskeyman

Thanks for that.
I think the problem is down to lack of pressure in the system now so.
When I bled some of the rads, no water or air comes out from some of them, especially upstairs.

The old boiler has no pressure gauge and I can't see a water valve going in near it anywhere.
Any ideas?

youtheman

Just looked up the Elan 2 manual on the internet. It can be used in a sealed (pressurised) set up or in an open (vented) setup. But if it is used in a sealed setup there should be a pressure gauge near the expansion vessel. I suspect the system has lost pressure and needs to be topped up, There most probably a top up valve in the hot press that needs to be opened. Maybe post some photos of the piping setup in the hotpress.

whiskeyman

Here ye go.

Thanks!

youtheman

Can't see a filling loop there. Is there anything hidden behind the cylinder?.

whiskeyman

youtheman wrote: »

Can't see a filling loop there. Is there anything hidden behind the cylinder?.

Nope. Just those pipes
No valves or anything.
There are 4 pipes going up to the attic. One has a turn valve, but that wouldn't be it, would it?