Loft rads not getting hot

[cf-leeds]

I had my loft convertoed just over a year ago and have 2 heat sources up there. A towel rail in the bathroom and a 2m x 30cm rad under the large window.

I'm in a 1930 large semi and have a Ecotec Exclusive 832 32kw combi.

I initially fitted the heating and used 10mm copper tubing, which has worked fine over the years.

When we had the loft converted, getting services up there was tricky and the plumber recommended putting a "T" from the landing heating tubes that feed the 1st floor small bedroom. He said that flow would not be an issue - wrong !!! (I relied on his superior experienced knowledge and yes he was clueless, but that's another story)

The rads in the loft dont get hot, but just warm. Despite numerous attempts at balancing, I cant get them red hot, like in the rest of the house.

I'm now considering radical solutions, like a dedicated boiler up in the loft, which wouldn't actually be that difficult to fit, though I'me told I'd need to ramp up my gas supply (at a cost?) - I'm wating for a call back on that from the supplier.

Can anyone offer any advice here - would pump speed make any difference ? I was looking at the Vailent setttings yesterday, and the pump is set to 60%.

Alterrnatively, I'll have to bite the bullet and look at getting a dedicated flow and return to the loft, which would be very invasive :(

Thanks in advance for any tips.

Chris

[Phil L]

"cf-leeds" <ciri...@googlemail.com> wrote in message
news:8e452140-e003-48a1...@googlegroups.com...

Is there air in the rads? - I presume you've tried bleeding them?

[cf-leeds]

Yep - bled them numerous times :(

[DerbyBorn]

cf-leeds <ciri...@googlemail.com> wrote in news:4cc7f319-27da-44ce-bb2a-
82e4bc...@googlegroups.com:

> Yep - bled them numerous times :(
>

Are you throttleing back the "easy" radiators?. Have you tried turning most
of the downstairs rads off - do the loft ones get hot then?

[Roger Mills]

What is the vertical distance between the boiler and the loft rads? What
is the static pressure in the system? Have you bled *both* sides of each
rad - i.e. with one valve open and the other closed, and then the other
way round - to make sure there's no air in either pipe? If you're sure
there's no air in the pipes, tweeking up the static pressure a bit *may*
help - as long as you don't overdo it, and exceed the blow-off pressure
when the system's hot.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

[Andrew Gabriel]

In article <4cc7f319-27da-44ce...@googlegroups.com>,

cf-leeds <ciri...@googlemail.com> writes:
> Yep - bled them numerous times :(

Can you get a little jet of water out of the bleed nipples, or just
nothing comes out?

When system has been on for a while, wre is the radiator hot? e.g.
Flow pipe?
Whole top edge?
Middle?
Bottom?
Just the inlet point and first vertical channel?
Return pipe?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

[Phil L]

"cf-leeds" <ciri...@googlemail.com> wrote in message
news:8e452140-e003-48a1...@googlegroups.com...

I had my loft convertoed just over a year ago and have 2 heat sources up
there. A towel rail in the bathroom and a 2m x 30cm rad under the large
window.

Where is the boiler situated?

It would be better on the 1st floor as it wouldn't have as far to pump,
although i worked on some 3 storey houses where the boiler was on the GF and
the 'loft' rads got as hot as all the others, although this was using 15mm
plastic pipe

[Graham.]

Does the circulating pump have variable speed settings??

--

Graham.

%Profound_observation%

[Dave Liquorice]

On Tue, 4 Nov 2014 07:39:07 -0800 (PST), cf-leeds wrote:

> Yep - bled them numerous times :(

Getting gas out each time? Has the system got inhibitor in it? The
FAQ has a good description on how to balanace a central heating
system. As it's all a bit interelated you have to go around several
times checking temps and waiting five to ten mins with the system
running after each change for the system to stabilse again. It's not
a quick process to do well.

--
Cheers
Dave.

[cf-leeds]

Thanks for all the suggestions - here's what I can verify:

Opening the bleed valves on the loft rads gives a pressurised solid flow of water. This is that case at each end of the large rad. The towel rail has one bleed valve only.

The flow tap on each rad is getting warm, just warm. On the towel rail, the return valve is also slightly warm. On the long window rad, the flow valve gets warm and one end of the rad is cold, though the rad is so long that the little heat there is probably dissipated before reaching the return valve - it seems.

I have been round all of the ground and first floor rads and completely closed the flow valve and then just cracked them open, i.e. open enough to maintain a hot temperature.

This made a small difference.

Then......

Checking the boiler, the thermostat dial was about just past half way round, So I've put it to 3/4 way round.

I now find that the rads in the loft are getting hot.

So - amoung other things, it seems that with the thermostat set to just past half way, the ground and firstl floor rads are red hot, but loft are cold.

With the thermostat higher, the loft rads start to kick in.

Maybe the bset thing here is to run heating with the thermostat higher, though I'll then have to regulate down the first and ground floor.

Make sense ? Maybe this will make the heating less efficient or maybe reducing flow to the ground and first floor rads will avoid the inefficiency ?

Thanks

Chris

[cf-leeds]

Yes - its set to 60% right now.

[harryagain]

"cf-leeds" <ciri...@googlemail.com> wrote in message
news:8e452140-e003-48a1...@googlegroups.com...

First thing is the system will need re-balancing, has this been done?
The lockshield valves on the radiatpors have to be adjusted so that the
water is forced around all parts of the circuit.

If it can't be balanced then the pump is too small or may need the speed
increased. (Check what the speed setting is.)
If it can't be balanced with the pump on the highest speed, then the
pipework used for the new radiators is too small.

You might find the system can be balanced but all the radiators in the house
are only warm. This indicates the boiler and/or the pump is too small.

It might be possible to fit a pump with higher performance to fix the
problem.
It's also possible your old/existing pump has worn and the performabce has
degraded significantly to what it was new.

[David]

One question I haven't seen asked.....

.....do you have thermostatic valves on all the radiators?

If you have thermostatic valves then once the room is up to temperature
the radiator will shut down and there will be more hot water for the rest
of the system.

Once the ground and first floor are up to temperature then all the
radiators will be shut down and all the heat should go to the loft (as
long as the main thermostat is still calling for heat).


Oh, and on the things you discussed initially, I have trouble visualising
how getting mains cold water plus a gas supply big enough to run a boiler
up to the loft in a way that is less invasive than running a flow and
return from your current heating.

Hove you considered a separate zone for the loft with its own thermostat
and pump? Possibly less expensive than a complete extra boiler and an
uprated gas main.

The experts should be able to tell you if a separate zone with e.g. 10mm
flow and return would be feasible.

Cheers

Dave R





--
Windows 8.1 on PCSpecialist box

[cf-leeds]

Thsnk for all advice - a few comments:

Balancing the system - I haven't yet done this scientifically, though I've found that opennig the valves just enough to get the rads hot on the ground and first floor has forced hot water into the loft rads.

Thermostatic valves - Kitchen, dining room and one bedroom have these. The loft ones don't have them.

Pump - This is a Vailent boiler about 3 years old and afaik is in perfect working order. The pump can be cranked up, as it's currently at 60%. I have no experience of doing that and would have to read up on it.

>I have trouble visualising
> how getting mains cold water plus a gas supply big enough to run a boiler
> up to the loft in a way that is less invasive than running a flow and
> return from your current heating.

Actually, there's an accessible void in the loft where heating pipes and cold water are easily accessible, as is access to the outside wall for flue. Therefore running a gas pipe up the outside wall to loft level would be the only challenge - This is probably a non-starter however, due to the increased gas supply that would be needed.

For now, i've managed to get the loft rads hot by some rudimentary balancing, though I'm thinking of biting the bullet and getting a dedicated flow and return to the loft. Evaluating the pipe routes here, I could be creative and get from the downstairs manifold (22mm > 6 x 10mm), up to the landing where the T for the loft is. The upstairs manifold is not accessible however without destroying a tiled floor.

Thanks

Chris

[Dave Liquorice]

On Wed, 5 Nov 2014 04:34:20 -0800 (PST), cf-leeds wrote:

> For now, i've managed to get the loft rads hot by some rudimentary
> balancing, though I'm thinking of biting the bullet and getting a
> dedicated flow and return to the loft.

Well if crude balancing has improved things immensely I'd carry on
and do it properly. Roll of black sticky tape and IR thermometer
makes taking each rads flow/return temp easy.

--
Cheers
Dave.

[F]

On 04/11/2014 15:18, cf-leeds wrote:

> Can anyone offer any advice here - would pump speed make any difference ? I was looking at the Vailent setttings yesterday, and the pump is set to 60%.

Increase the pump speed to maximum, turn off all radiators other than
the ones in the loft, run it like that for twenty minutes or until the
radiators get properly hot. That should ensure that you have driven out
any residual air in the pipes that feed those radiators.

Then re-open all of the other radiators and rebalance.

--
F