Hi,
Three components and their interactions I've been trying to get my head around for a while now!
I currently have the Evohome system installed on a system with a MANUAL bypass valve, along with a single radiator (large and one of furthest away on the system) WITHOUT an Evohome TRV.. the latter in part not by choice (this is the hallway where the old room stat used to be and therefore no TRV body to easily clip a Evohome head to) however actually works reasonably well as this area is by far the coldest area in the house so benefits from the extra heat. I also have replaced my old knackered pump with an Alpha2 pump (which includes the ability to auto-adapt, a useful feature for a 14 rad system across 3 floors that will often be run with only a few rads open). Lastly this is a y-plan setup with flow and return.
Firstly, the manual bypass. While I understand its purpose (open just enough to ensure that if all the rads are closed there will still be the minimum flow required so as not to overheat the boiler, knacker the pump etc) and while I'm sure such a thing was invented by someone who knows much more about heating systems than myself (!) I simply can't see how having this left permanently in this "a bit open" state can be efficient?! Surely whenever I'm say heating water I'm wasting heat diverted through the bypass unnecessarily. Similarly when heating rads - surely I want all the heat channeled to the rads and not some escaping via a shortcut back to the return?!
Now in my setup at the moment I *always* have a single radiator open, so I don't think I actually *need* a bypass at all as the radiator itself acts as a bypass (I'm talking practically here, not per perhaps the latest building regs. or to cover extremely unlikely scenarios that someone would access this radiator behind its boxed cover and inexplicably turn it off!), with this in mind I've previously completely closed the manual bypass gate with no ill-effect (can't remember how it is right now, might have reopened it a little).
This said I would prefer to have control over this last radiator (fitting a TRV body and Evohome head to it) and therefore THINK I would like an automatic bypass valve fitted. I understand how these work (setup to provide minimum flow rate when all rads closed, otherwise will remain closed itself) and like the idea HOWEVER I'm concerned whether or not this 'variable' will counteract the auto adapting pump?? ie. with both on the same system will the minimum flow rate still be maintained or will they be canceling each other out / constantly trying to readjust?
If they aren't compatible I see two choices: 1) stick with a manual bypass that is setup correctly (hopefully after someone here has reassured me the wastage I'm imagining is negligible!) or 2) go with an auto bypass and run my pump in standard fixed mode (though would seem like I'm wasting a useful feature)
Numerous question here I know - sorry - this is hopefully my last bit of knowledge gap I need filling of my CH system!
Three components and their interactions I've been trying to get my head around for a while now!
I currently have the Evohome system installed on a system with a MANUAL bypass valve, along with a single radiator (large and one of furthest away on the system) WITHOUT an Evohome TRV.. the latter in part not by choice (this is the hallway where the old room stat used to be and therefore no TRV body to easily clip a Evohome head to) however actually works reasonably well as this area is by far the coldest area in the house so benefits from the extra heat. I also have replaced my old knackered pump with an Alpha2 pump (which includes the ability to auto-adapt, a useful feature for a 14 rad system across 3 floors that will often be run with only a few rads open). Lastly this is a y-plan setup with flow and return.
Firstly, the manual bypass. While I understand its purpose (open just enough to ensure that if all the rads are closed there will still be the minimum flow required so as not to overheat the boiler, knacker the pump etc) and while I'm sure such a thing was invented by someone who knows much more about heating systems than myself (!) I simply can't see how having this left permanently in this "a bit open" state can be efficient?! Surely whenever I'm say heating water I'm wasting heat diverted through the bypass unnecessarily. Similarly when heating rads - surely I want all the heat channeled to the rads and not some escaping via a shortcut back to the return?!
Now in my setup at the moment I *always* have a single radiator open, so I don't think I actually *need* a bypass at all as the radiator itself acts as a bypass (I'm talking practically here, not per perhaps the latest building regs. or to cover extremely unlikely scenarios that someone would access this radiator behind its boxed cover and inexplicably turn it off!), with this in mind I've previously completely closed the manual bypass gate with no ill-effect (can't remember how it is right now, might have reopened it a little).
This said I would prefer to have control over this last radiator (fitting a TRV body and Evohome head to it) and therefore THINK I would like an automatic bypass valve fitted. I understand how these work (setup to provide minimum flow rate when all rads closed, otherwise will remain closed itself) and like the idea HOWEVER I'm concerned whether or not this 'variable' will counteract the auto adapting pump?? ie. with both on the same system will the minimum flow rate still be maintained or will they be canceling each other out / constantly trying to readjust?
If they aren't compatible I see two choices: 1) stick with a manual bypass that is setup correctly (hopefully after someone here has reassured me the wastage I'm imagining is negligible!) or 2) go with an auto bypass and run my pump in standard fixed mode (though would seem like I'm wasting a useful feature)
Numerous question here I know - sorry - this is hopefully my last bit of knowledge gap I need filling of my CH system!
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