Hi all.
I have done several adaptions to my boiler including supplementing the central
heating with a hot pre feed so my boiler runs 100% on the external source via
a plate heat exchanger. This has worked extremely well over the winter, and
the same heat source will be heating the pool ( when I set it up sometime soon
). I have been toying with the idea of linking onto this loop for a second
time, that's already in place, using another plate heat exchanger to run the
hot water for the house. The loop can run at anywhere from 62 degrees up to
around 90 degrees c depending on my choice and I was thinking that if I can
link into my cold feed in ( the same as I have linked into the CH loop to put
hot water pre boiler ) I should be able to stop the boiler firing up and
therefore use no gas.
I have read what feels like hundreds of articles but I cannot find whether or
not I can do this on my old boiler.
Has anyone tried this before or can I simply not feed hot water into the
boiler?

Hope someone can help.
Thanks
David

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On Tuesday, 23 April 2019 21:44:06 UTC+1, Davidcorlett wrote:

Hi all.
I have done several adaptions to my boiler including supplementing the central
heating with a hot pre feed so my boiler runs 100% on the external source via
a plate heat exchanger.

What is this 'hot prefeed'. What is this 'external source'.

This has worked extremely well over the winter, and
the same heat source will be heating the pool ( when I set it up sometime soon
). I have been toying with the idea of linking onto this loop for a second
time, that's already in place, using another plate heat exchanger to run the
hot water for the house. The loop can run at anywhere from 62 degrees up to
around 90 degrees c depending on my choice and I was thinking that if I can
link into my cold feed in ( the same as I have linked into the CH loop to put
hot water pre boiler ) I should be able to stop the boiler firing up and
therefore use no gas.
I have read what feels like hundreds of articles but I cannot find whether or
not I can do this on my old boiler.
Has anyone tried this before or can I simply not feed hot water into the
boiler?

Hope someone can help.
Thanks
David

There's no harm is having another heat source in your CH primary loop of course. As for the cold feed I don't know, can you examine/identify the materials in the relevant part of the boiler? Is there a fault code in the manual for input too hot? What will it modulate down to? How are you going to control temp for legionella safety?

There are others here with much more knowledge & experience on heating systems. But the website you're using is blocked by most folk here. You can get here via google groups or a newsreader.


NT

Probably a roof mounted water heater. a friend has one and seems to hardly
use any gass.
Brian

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On Tuesday, 23 April 2019 21:44:06 UTC+1, Davidcorlett wrote:

Hi all.
I have done several adaptions to my boiler including supplementing the
central
heating with a hot pre feed so my boiler runs 100% on the external source
via
a plate heat exchanger.

What is this 'hot prefeed'. What is this 'external source'.

This has worked extremely well over the winter, and
the same heat source will be heating the pool ( when I set it up sometime
soon
). I have been toying with the idea of linking onto this loop for a
second
time, that's already in place, using another plate heat exchanger to run
the
hot water for the house. The loop can run at anywhere from 62 degrees up
to
around 90 degrees c depending on my choice and I was thinking that if I
can
link into my cold feed in ( the same as I have linked into the CH loop to
put
hot water pre boiler ) I should be able to stop the boiler firing up and
therefore use no gas.
I have read what feels like hundreds of articles but I cannot find whether
or
not I can do this on my old boiler.
Has anyone tried this before or can I simply not feed hot water into the
boiler?

Hope someone can help.
Thanks
David

There's no harm is having another heat source in your CH primary loop of
course. As for the cold feed I don't know, can you examine/identify the
materials in the relevant part of the boiler? Is there a fault code in the
manual for input too hot? What will it modulate down to? How are you going
to control temp for legionella safety?

There are others here with much more knowledge & experience on heating
systems. But the website you're using is blocked by most folk here. You can
get here via google groups or a newsreader.


NT

replying to tabbypurr, Davidcorlett wrote:
I am running a bairan 120p waste oil burner in a camray CH boiler unit. It
heats and maintains a 65-90 deg C temp. This is the loop, as it is external to
the house. The loop runs up to the house where I have linked it into the CH in
feed via a plated heat exchanger.
I am fairly certain there are no plastic parts in these older boilers but I am
not sure if I feed in water via the heat exchanger ( so the loop water will
_never mix _ with the shower or tap water so no legionella problem ) will the
boiler just continue to heat. Don't want super heater hot water or to destroy
the boiler or worse.... Has worked really well through these last months and
save me at least 60% of my last original gas bill. Just want to utilise the
remaining heat for the hot water.
Thanks for the reply.
David

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for full context, visit https://www.homeownershub.com/uk-diy...r-1357877-.htm

replying to Brian Gaff, Davidcorlett wrote:
Hi Brian,
I had looked into this option but the initial outlay was not going to justify
the expense. It would have taken several years to recoup the costs. A roof
mounted unit like those in Spain etc are really good and definitely a cheaper
option but I just want to add onto what I already know works, as the main
costs of the unit, burner, pipework, insulation, supports etc had already been
spent. I have another 20 plate heat exchanger and it would only be integrating
this new exchanger into the cold in feed. If I can get this to work, the
boiler is only then a means of heat transfer and pump. Have already got back
what I spent to put this together last year as I sold the oil burner which
came with the boiler, that paid for most of the bits and the plate heat
exchanger. Everything's sadly always on a tight, if not non existent budget

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for full context, visit https://www.homeownershub.com/uk-diy...r-1357877-.htm

On Monday, 29 April 2019 15:14:04 UTC+1, Davidcorlett wrote:
replying to tabbypurr, Davidcorlett wrote:

I am running a bairan 120p waste oil burner in a camray CH boiler unit. It
heats and maintains a 65-90 deg C temp. This is the loop, as it is external to
the house. The loop runs up to the house where I have linked it into the CH in
feed via a plated heat exchanger.
I am fairly certain there are no plastic parts in these older boilers but I am
not sure if I feed in water via the heat exchanger ( so the loop water will
_never mix _ with the shower or tap water so no legionella problem ) will the
boiler just continue to heat. Don't want super heater hot water or to destroy
the boiler or worse.... Has worked really well through these last months and
save me at least 60% of my last original gas bill. Just want to utilise the
remaining heat for the hot water.
Thanks for the reply.
David

Every sane boiler has a temp detector that reuslts in it cutting heat when it reaches target temp, and has had for a long old time. It's certainly not going to overheat. The question is what the onboard software will make of the initial high temp, it might assume it's an internal error & shut down.

If it does do that, perhaps you could use a thermostatic mixer valve to remedy things by having it bypass the boiler when the water's already hot, and go through the boiler when it's not. Feed your preheated feed into the TMV's output. I've not tried doing that, just an idea to consider.


NT

replying to tabbypurr, Davidcorlett wrote:
I see what you're getting at. Am just wondering if I could do it more simply.
Just get the boiler to pump when the tap is opened, but not fire up? I am
guessing that the control unit would be the point of focus but after all, if
the drop or flow caused by the opening of the tap causes a sensor to then run
the pump and ignite the boiler, I just want to block that firing up.
All manuals do the fault diagnosis and fix to create the ignition, not to stop
it.

Will keep thinking.
Thanks for all the advice. Very much appreciated.
David

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for full context, visit https://www.homeownershub.com/uk-diy...r-1357877-.htm

On Friday, 3 May 2019 16:14:04 UTC+1, Davidcorlett wrote:
replying to tabbypurr, Davidcorlett wrote:

I see what you're getting at. Am just wondering if I could do it more simply.
Just get the boiler to pump when the tap is opened, but not fire up? I am
guessing that the control unit would be the point of focus but after all, if
the drop or flow caused by the opening of the tap causes a sensor to then run
the pump and ignite the boiler, I just want to block that firing up.
All manuals do the fault diagnosis and fix to create the ignition, not to stop
it.

Will keep thinking.
Thanks for all the advice. Very much appreciated.
David

I doubt you can modify what it does & not have it shut down reporting a fault.
You might just get away with heating its internal store externally, maybe. That way it doesn't need to do anything outside its usual routine.


NT