Loft rads not getting hot

[cf-leeds]

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

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 worke d fine over the years.

When we had the loft converted, getting services up there was tricky and th e plumber recommended putting a "T" from the landing heating tubes that fee d the 1st floor small bedroom. He said that flow would not be an issue - wr ong !!! (I relied on his superior experienced knowledge and yes he was clue less, 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 lo ft, 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 dedicate d flow and return to the loft, which would be very invasive :(

Thanks in advance for any tips.

Chris

[DerbyBorn]

cf-leeds wrote in news:4cc7f319-27da-44ce-bb2a- [e-mail]:

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

[Andrew Gabriel]

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?

[Graham.]

Does the circulating pump have variable speed settings??

[Dave Liquorice]

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.

[cf-leeds]

there. A towel rail in the bathroom and a 2m x 30cm rad under the large win dow.

ked fine over the years.

the plumber recommended putting a "T" from the landing heating tubes that f eed 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 cl ueless, but that's another story)

ts at balancing, I cant get them red hot, like in the rest of the house.

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 o n that from the supplier.

I was looking at the Vailent setttings yesterday, and the pump is set to 6

0%.

ted flow and return to the loft, which would be very invasive :(

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 t he little heat there is probably dissipated before reaching the return valv e - it seems.

I have been round all of the ground and first floor rads and completely clo sed the flow valve and then just cracked them open, i.e. open enough to mai ntain 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 pas t 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, tho ugh I'll then have to regulate down the first and ground floor.

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

Thanks

Chris

[cf-leeds]

there. A towel rail in the bathroom and a 2m x 30cm rad under the large wi ndow.

rked fine over the years.

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 c lueless, but that's another story)

pts at balancing, I cant get them red hot, like in the rest of the house.

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.

? I was looking at the Vailent setttings yesterday, and the pump is set to

60%.

ated flow and return to the loft, which would be very invasive :(

Yes - its set to 60% right now.

[harryagain]

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

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

[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 w orking 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.

Actually, there's an accessible void in the loft where heating pipes and co ld 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 increa sed gas supply that would be needed.

For now, i've managed to get the loft rads hot by some rudimentary balancin g, though I'm thinking of biting the bullet and getting a dedicated flow an d 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 w here the T for the loft is. The upstairs manifold is not accessible however without destroying a tiled floor.

Thanks

Chris

[Dave Liquorice]

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.

[F]

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.