Central Heating bypass Question

[dormermike]

Hello

I wonder if someone can advise me please - first some information: I have a central heating system with a hot water tank and seperate boiler.. powers the radiators and the hot water. Its a pretty standard setup I think. There is a expansion tank for the central heating, and a seperate larger tank for the hot water cylinder.

All radiators have TRV's except a small rad in the airing cupboard upstairs, which is in the same space as the hot water tank and expansion tanks.

Thinking this little radiator was useless i switched it off - and the system got very noisy. I learnt that this rad is critical as a bypass in case the TRV's are closed.

Luckily no damage done.

So, since then i've removed the TRV from the downstairs bathroom radiator.

Am I correct in saying it should now be safe to switch off the radiator in the airing cupboard - the "bypass" one? Or should I just leave it well alone? I want to switch off ideally as its not needed in the airing cupboard.

Second question, i get a small amount of air in this airing cupboard/bypass rad, and also at two bleed points (x1 HW, x1 CH) - I suppose I can bleed them every month or so and a bit of air comes out.

I can see no evidence of a leak, but I suppose there must be one somewhere?

Thanks
Mike

 

[Agile]

Generally I would have said dont change it if its working.

But do as you suggest and see if it works OK with the trvs all closed.

Tony

 

[dormermike]

Tbh, good point - if it aint broke, dont try to fix it. My old man told me that years ago and the number of times i've heard his voice ringing out in my head after something goes wrong. I do tend to tinker I does.

OK, will leave it.. perhaps.

Cheers

 

[moggridgeplumbing]

Firstly the little radiator in the airing cupboard, is most probably the bypass radiator, and is the one which needs to stay open, or if you don't want the rad then has to be modified to act as a bypass (heating eng needed). You can refit your trv on your downstairs bathroom rad, as I assume (not having inspected it), it is on the Central Heating circuit. The bypass is on the main primary circuit, and the idea is that if your demand for central heating and hot water is switched off there is still a circuit which the water can still circulate as the system cools down.

As regarding the air problem. It could be air being drawn in through the expansion pipe going to your Feed and Expansion tank, or your pump is pumping over. Check the feed and expansion tank to see if it has any hot water in it. Then again it maybe that your system is very contaminated and needs a good flush. Does the boiler make any kettling noises?

Lots of questions I know, but difficult to diagnose without checking a lot of things. Hope the info helps.

 

[dormermike]

Firstly the little radiator in the airing cupboard, is most probably the bypass radiator, and is the one which needs to stay open, or if you don't want the rad then has to be modified to act as a bypass (heating eng needed). You can refit your trv on your downstairs bathroom rad, as I assume (not having inspected it), it is on the Central Heating circuit. The bypass is on the main primary circuit, and the idea is that if your demand for central heating and hot water is switched off there is still a circuit which the water can still circulate as the system cools down.

As regarding the air problem. It could be air being drawn in through the expansion pipe going to your Feed and Expansion tank, or your pump is pumping over. Check the feed and expansion tank to see if it has any hot water in it. Then again it maybe that your system is very contaminated and needs a good flush. Does the boiler make any kettling noises?

Lots of questions I know, but difficult to diagnose without checking a lot of things. Hope the info helps.

Aha!! Thank you - didnt consider/recognise that the bypass would be on a different circuit to the central heating system. I'll leave it well alone. The reason for TRV removal in the downstairs bathroom was because the rad is too small and I wanted it on all the time, so TRV surplus to requirements. Needs a bigger rad really.

Regarding the air, the boiler does not make a kettling noise (it did when I closed the bypass rad!!) and the expansion tank has water in it. The expansion tank never gets hot, even when we had the boiler on "5" during the depths of our recent cold spell. I removed a downstairs rad recently (not cause of this problem btw, same prob before and after refitting) and the water colour was fine - no sludge at all. I think the system was well looked after and seems to be well put together, judging by the nice neat solder joints on the pipework etc (especially when compared to the awful messy job the corgi fitter did when fitting my hob recently).

Cheers, very helpful bunch on here!

Mike

 

[chrismp]

Sorry to butt in here - I have a bypass related conundrum too.

Our boiler has packed up and after 4 fruitless visits, the service company that I have paid £300 per year for have decided the installation is wrong. The boiler is a Glow Worm 30sxi condenser. After the last visit the guy seemed to run off muttering something about the system not having a "permanent live supply" (which it does have via a switched fused spur) or an "external bypass". As a result they cant fix it and want more money to come out again once I have addressed these issues. Does anyone know if the external bypass is necessary on a 30sxi? Looking through the manual I have found reference to an internal bypass, so is that not relevant? And surely if the boiler is getting 240v, then its getting 240v! The whole system has worked fine since it went in 3 years ago. Kind of feel like I am being scammed here....
3 weeks no heating! And counting.

Thanks for any help/advice in advance

 

[45yearsagasman]

Very few people will assist on a hijacked thread.Post again.

 

[chrismp]

apologies - i thought the original query was sorted.

 

[Agile]

Sorry to butt in here - I have a bypass related conundrum too.

Thanks for any help/advice in advance

Better to stay on your own thread and read the answers that we have given.

You would not want anyone posting their totally irrelevant comments on your thread would you?

Tony