Ecotech adjustable bypass valve

[Cheerychap]

Hi

I need some advice about my system/Valliant echotec 837

Just for context – it’s a big house – 18 radiators in total. The boiler was fitted over 10 years ago, with, I think, not much concern by the fitter, either around balancing the system or the number of radiators.

So, for e.g. - We’ve always had a problem with pressure (no matter how low I start the pressure at cold, it goes very near 3 bar when hot)– which I now know (because its in black and white in the manual!) is because the internal 10l expansion vessel wasn’t big enough – because of this I’ve just fitted an external expansion vessel. This has worked well.

I balanced the system as well as I could a few years ago, using appropriate thermometers and trying to achieve a 20c drop over as many rads as possible. I say ‘as well as I could’ because its an old house (450 years!) with pipework that is a bit of a spaghetti junction – the rads don’t follow a very linear path, with, I suspect, loops being taken off at various places to feed various rooms.

Anyway – my question is around the integrated adjustable by-pass valve in the echotech 837. All the rads but one (i.e. where we have the thermostat) have TRVs. I know the purpose of the by-pass is to ensure that there is still a loop of water to circulate, should all the TRVs be closed – however, as we have one rad always open, my simple question is, can I shut off this bypass valve as much as possible? - according to the manual it can’t be shut off completely, but can go between 170 and 350 mbar. So I’d like to go for 350mbar

The reason I ask is because the overall difference between boiler flow and return is generally only about 12 C, despite most of the rads having a greater drop than this and I suspect that some of this is caused by hot water just taking a very short trip around the boiler via the bypass valve. To make the obvious point – a larger temp drop would be a good thing in terms of condensing as the return will spend more time (and a greater amount) under 55c

2 other things:

1) I have considered changing the pump speed (it has 2 speeds, so could go for the lower one), as I’m guessing this would help the temp difference – but it is a big house, so I’m worried that this will not leave enough heft to get the water properly round the system

2) I read the ideal would be to have an automatic bypass fitted – though I suspect that given the boiler has an integrated non-automatic one, this may not be possible (as how could the integrated one be bypassed or blocked?)

So my main question is – can I go ahead and shut off the bypass as much as possible, given that I have a non TRV rad in the system? But thoughts around pump speed and having an automatic bypass fitted would also be great

Thanks so much in advance

Dave

 

[ianmcd]

Leave it alone , I know not what you want to hear, but unless you are a professional , dont mess with it

 

[muggles]

So my main question is – can I go ahead and shut off the bypass as much as possible, given that I have a non TRV rad in the system?

No, you can't, because it's inside the room-sealing casing of the boiler, which should only be accessed by a Gas Safe Registered engineer

 

[Cheerychap]

Thanks for the replies – sorry should have been clearer – I’ve no intention of removing the boiler cover myself – in a lengthy enough post, I was trying to be to the point – what I meant was ‘is it worth getting a plumber to come in and look at adjusting the bypass valve, or have I completely missed the point of what a bypass valve is, and it would be a waste of everybody’s time (and my money!)?’