Switching to BBOE

[gluepack]

We are in Bulgaria and have a four winter old central heating system installed with TBOE fittings (apart from end of line that are TBSE and a towel rail that is BBOE). Pipework is (I think) pvc with metal interior, 15mm od, and compression fittings are used. RVs are 90° and on the hot entry side. Additionally, the wood burning stove that feeds the system has a pump that pushes the cold return into the stove. The system was installed, as part of a property renovation, by a “meister” but, in this country, that doesn’t mean a lot.

Despite attempts at balancing, the radiators barely get hot in other than the top 15cm (apart from the towel rail) and, if they do, the bottom of the entry side never gets warm, let alone hot.

I feel that…
a) my previous experience…
…I have had several different central heating systems, wood, oil and gas fuelled, over the years and they have all been BBOE,
b) theoretical knowledge of physics…
…surely, convection of the heat from the circulating water will eventually provide a relatively even heat across the face of the radiator. Not only that, the return water will be warmer and take less time/energy to reheat,
c) and the gist of most of the threads…
…most comments suggest that, in a modern system, the radiators should be fitted as BBOE…
would suggest that I should switch them all to BBOE but I would like confirmation of that, please.

If I do, in changing the end of line radiators, should I have the hot going in first, as with the other radiators or is there any benefit to having it go into the far end instead?

Typically, all pipes are exposed and running along at skirting board level. Consequently, at present, the pipe in (at the top) has sufficient length from the skirting board that the RVs are vertical. With BBOE, they might work better at a 45° angle from the wall and are unlikely to project any distance if they were. Is that likely to make much difference (it is doubtful that any RVs will be ever closed off)?

 

[muggles]

TBOE is supposed to be more efficient. The thing you need to be concerned with is not whether your radiators are hot, but whether your rooms are warm enough. If they are, stop worrying about it, if they aren't then there is a problem. BBOE is generally used because it looks nicer, but it's not actually the best way of installing a system!

 

[gluepack]

TBOE is supposed to be more efficient

Well, either it is or it isn’t.
Radiators are supposed to be radiators of heat, hence the name.
Given the fact that the radiators I have are e.g. 60 cm x 45 cm, I would say they would be as, if not more, efficient if they were only 60 cm x 15 cm as that is the only area that gets hot. Also, if TBOE is more efficient then a 60 cm x 15 cm radiator placed at 45° angle on the wall should be great. However, I have never seen radiators that size and placed at 45° (perhaps down a staircase somewhere).
I would suggest that they are built rectangular and placed horizontally for a reason.

The thing you need to be concerned with is not whether your radiators are hot, but whether your rooms are warm enough. If they are, stop worrying about it, if they aren't then there is a problem.

Err… I don't think cold radiators will warm a room (certainly when it is -17 outside, as it is here) and I don’t think I would bother to join a forum to ask a question like this if the radiators were performing the way I expected. I have never had a heating problem before (in 45 years of radiator ownership) and the radiators have always been BBOE and all-over warm/hot.

My critical remark with regard to “meister” is relevant as the modification of houses in this part of the world to provide for central heating (indoor toilets as well) is relatively new and, given the standard of most renovations I have seen here, I wouldn’t be surprised if they only fitted them TBOE because that is what they have seen in some communist era manual from 50 years ago.

BBOE is generally used because it looks nicer, but it's not actually the best way of installing a system!

My question was rather simple. Your answer is irrelevant.

 

[D_Hailsham]

TBOE is supposed to be more efficient

Well, either it is or it isn’t.

TBSE is the most efficient followed by TBOE and the BBOE; but there's only a 1or 2% difference between TBSE and BBOE!

Radiators are supposed to be radiators of heat, hence the name.

The correct name is "emitter". The amount of heat given of by direct radiation is low compared to that given off by convection.

I don't think cold radiators will warm a room (certainly when it is -17 outside, as it is here)

Agreed, but you are jumping to the conclusion that it is due to the way the rads are connected.

Therer could be many causes for your house not getting hot enough and the last one to consider is how the rads are connected. Possible culprits, in no particular order, are:

1. Rads not large enough - you can't expect rads sized for a temperature of -1C to work for a temperature of -17C;

2. Boiler not large enough - same reason as above;

3. System not correctly balanced;

4. System sludged up;

5. Faulty pump.

I wouldn’t be surprised if they only fitted them TBOE because that is what they have seen in some communist era manual from 50 years ago.

TBSE and TBOE have been standard for years throughout the continent. You will also find that UK commercial installations are mostly TBSE or TBOE as efficiency is more important that aesthetic considerations.

 

[mysteryman]

Yes, TBSE gives the best output, but there is a circulation problem here.

 

[muggles]

TBOE is supposed to be more efficient

Well, either it is or it isn’t.
Radiators are supposed to be radiators of heat, hence the name.
Given the fact that the radiators I have are e.g. 60 cm x 45 cm, I would say they would be as, if not more, efficient if they were only 60 cm x 15 cm as that is the only area that gets hot. Also, if TBOE is more efficient then a 60 cm x 15 cm radiator placed at 45° angle on the wall should be great. However, I have never seen radiators that size and placed at 45° (perhaps down a staircase somewhere).
I would suggest that they are built rectangular and placed horizontally for a reason.

The thing you need to be concerned with is not whether your radiators are hot, but whether your rooms are warm enough. If they are, stop worrying about it, if they aren't then there is a problem.

Err… I don't think cold radiators will warm a room (certainly when it is -17 outside, as it is here) and I don’t think I would bother to join a forum to ask a question like this if the radiators were performing the way I expected. I have never had a heating problem before (in 45 years of radiator ownership) and the radiators have always been BBOE and all-over warm/hot.

My critical remark with regard to “meister” is relevant as the modification of houses in this part of the world to provide for central heating (indoor toilets as well) is relatively new and, given the standard of most renovations I have seen here, I wouldn’t be surprised if they only fitted them TBOE because that is what they have seen in some communist era manual from 50 years ago.

BBOE is generally used because it looks nicer, but it's not actually the best way of installing a system!

My question was rather simple. Your answer is irrelevant.

Wow that's quite an attitude you've got there, carry on like that and every pro on this site will quickly lose interest in trying to help you. I'll leave you to them, I've lost interest already

 

[Onetap]

Yes, TBSE gives the best output, but there is a circulation problem here.

I thought that, but there was an article in some journal that showed BBOE gave the most heat output, about 10% diference ISTR. TBOE is a hang-over from gravity circulation systems, it shouldn't make a lot of difference. It sounds to me more like a lack of heat input in this case, unless the boiler is actually boiling.

The radiator manufacturers probably publish data giving ratios of the output at various configurations.

 

[D_Hailsham]

Yes, TBSE gives the best output, but there is a circulation problem here.

I thought that, but there was an article in some journal that showed BBOE gave the most heat output, about 10% difference ISTR.

Stelrad Stars program allows you to specify which connection arrangement is used. As I said earlier, TBSE gives the highest output followed by TBOE with BBOE lagging 1 - 2% behind.