upstairs rads stone cold, downstairs red hot

fannyadams

Hi everyone,
just changed the valve on one of the large bore rads upstairs thinking that this was what was causing the 4 upstairs rads to be cold.
whole system drained down from the drainage tap thing (you know, the stubby pipe thing at the lowest point of the sysytem) beforehand and filled and inhibitor added to the F&E tank.
it's not fixed it.

We have a Gloworm 56/2 back boiler with a gas fire in front this is in the front room. This was installed in 2000, to replace our heating/fire-in-the-lounge thingy that was condemned after I had my gas cooker plumbed in by a CORGI registered plumber.

Downstairs there is one rad with a TRV (this is the ONLY rad that has a TRV) and then a long run of pipe to another rad in the extension, these both work fine and are really really hot (hadn blistering).
upstairs there are two large bore rads (in the kids rooms - back to back on an internal wall) and two small bore rads (one in our bedroom and the other in the bathroom both also on internal walls).
switching off the rads downstairs has made NO difference to the rads upstairs. they are still cold and now so are the downstairs rads. but if you switch on the downstairs rads they get hot again.

Quirky 'features' of our heating system, (as a heating engineers daughter I have not seen this set up before):

No, it doesn't seem to have a way of running JUST the heating circuit. you have the hot water on separately or you have the water and heating on. you can't JUST have the heating on. there is no thermostat on the hot water cylinder
when you have the hot water circuit on the two big bore rads get warm, but this isn't happening this time round.
we do have a room thermostat at the foot of the stairs.
there is two tanks in the loft one is small and I reackon is the F&E ( the water in here is cold) and the other must be the tank for the hot water fill.

OK so over to you guys/gals does anyone know how we can fix this before I call out the plumber.
Thank in advance for your advice and help.
FA
x

southcoastrgi

gravity hot water pumped heating, if thats the case no you can't have heating on seperatly

have you bled the upstairs rads ?

if you drain from the drain c0ck does the f&e tank re-fill ?

if not then you have an airlock or blocked cold feed

plumb1_2

As above, vent rads or air lock. Check feed for any blockage?

fannyadams

thanks for responses so far.
so if it is gravity fed, should it have a pump on the return side?
upstairs rads have been bled and are full i.e. water comes out when the bleed valve is open.
will have a go with drain !!!! on weekend.

how can we sort this airlock out?

Mr_Ted

Umm, your a heating engineers daughter, WHY are you asking on here:rotfl:

fannyadams

Mr_Ted wrote: »

Umm, your a heating engineers daughter, WHY are you asking on here:rotfl:

and your (Mr Ted's) sig says
"I am always willing to offer a constructive opinion by way of assisting with matter that I have experience of, but I will respond in kind to derisory personal comment, thats called SELF DEFENSE, so if you intend to offend please expect to be offended!"
the underlining is mine.

As you asked I'll tell you - but I'm gonna bet you've trolled here on this thread and don't come back since you have not 'offered a constructive opinion to assist me'...

1) because my Dad is dead so I can't ask him.
2) I didn't follow my dad into his trade, I am a Biological Scientist.
3) I mentioned it so that any replies could use more technical/plumber's language and I'd understand what they meant rather than when the reply on most forums mentions a specialist piece of plumbing and the next question is usually "what's one of those" or "what does that look like"

HAPPY NOW?

fannyadams

southcoastrgi wrote: »

gravity hot water pumped heating, if thats the case no you can't have heating on seperatly

AH HA! I think my dad might have mentioned something like this before.

southcoastrgi wrote: »

have you bled the upstairs rads ?

yes and nothing but water somes out.

southcoastrgi wrote: »

if you drain from the drain c0ck does the f&e tank re-fill ?

yes that bit is fine no problem.

although it did go dry in the summer and we only noticed when the boiler refused to fire up to heat the water.
went up in the loft and jiggled the ball c0ck assembly and it's been fine ever since.
is it possible that this might have had a knock on effect with the heating?

southcoastrgi wrote: »

if not then you have an airlock or blocked cold feed

assume you mean Cold feed to F&E, this is OK as when you jiggle the ball c0ck assembly water flows into the F&E tank. the cold feed to the hot water tank is also fine as when you run the hot tap you can hear the cold water filling it up and the feed pipe goes cold.

can I chase an airlock out the system?
would this mean pushing mains water in from the drain c0ck - at the lowest point of the system i.e. where we drained the system from originally? - back up to the F&E tank in the loft?

fannyadams

plumb1 wrote: »

As above, vent rads or air lock. Check feed for any blockage?

rads are bled - no air just water.
check feed for blockage? you mean cold feed into F&E, or another feed?

Cold feed not blocked.

was wondering if a horizontal run could have the air lock in it. if so how could I chase this out without pulling up floorboards?

fannyadams

moving on:
We have opened up the pump housing and spun the pump manually with a screw driver - it spins freely and isn't air locked or broken in any way.

We have bled all the rads and nothing but water comes out of all of them

We have switched off the downstairs rads using the lockshield valves again and switched off all but one radiator upstairs using same lockshield valves but this radiator (small bore in our bedroom) STILL isn't getting hot.

where to next?

Slowly_does_it..

Sounds to me like you still have an airlock! Also you mention that the header tank ran dry a while ago, this would also mean airlock to me.

Suggest turning downstairs rads off, leaving all upstairs rads on, then try and get the water flowing with the pump on. Temporarily increase the pump (if it is one of the pumps with speed settings)? drain one of the upstairs rads? Watch, water might start coming out rather warm!

Maybe find the plumbing, where it goes from the boiler downstairs to the rads upstairs, is there a bleed valve at the top of the vertical piping run - or a drain at the bottom of that run?

Also check that while you are letting water out of the system that the header tank does not run dry again!

Mr_Ted

fannyadams wrote: »

and your (Mr Ted's) sig says
"I am always willing to offer a constructive opinion by way of assisting with matter that I have experience of, but I will respond in kind to derisory personal comment, thats called SELF DEFENSE, so if you intend to offend please expect to be offended!"
the underlining is mine.
As you asked I'll tell you - but I'm gonna bet you've trolled here on this thread and don't come back since you have not 'offered a constructive opinion to assist me'...
1) because my Dad is dead so I can't ask him.
2) I didn't follow my dad into his trade, I am a Biological Scientist.
3) I mentioned it so that any replies could use more technical/plumber's language and I'd understand what they meant rather than when the reply on most forums mentions a specialist piece of plumbing and the next question is usually "what's one of those" or "what does that look like"
HAPPY NOW?

I apologies as it wasnt trolling, it just didnt make sense, not knowing the ACTUAL circumstances, why when it appeared you had someone with the necessary knowledge to resolve the situation you were seeking advise on here

My advise is that you need to upgrade the system to a fully pumped system, so that you have independent control of either heating or HW, and I would also consider using an RF digital controls/thermostat system:)

I think it is quite possible you may have a magnetite build up somewhere, due to the age of the system and type, that is causing the problem, and it is quite possible that in doing the upgrade the source will be found within the pipework that will need to be altered