I am replacing the water heater in my boat. The new one is an
"Ariston BLU EVO RS 10U BM EU", it's this one:-
https://www.amazon.fr/dp/B08HZXYYS3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
The installtion instructions come in lots of languages, including
English. I've installed very similar ones in the UK so I know the
basics.
However the instructions don't say whether a 'pressure relief' device
is mandatory, they just say "Some countries may require the use of
hydraulic special safety devices". It hasn't been supplied with one
and the similar heaters I have installed in the UK don't have one,
they just specifiy how much inlet pipe there must be before a tap
(i.e. space for expansion back down the pipe).
I will be installing with flexible reinforced PVC on the inlet side
(pretty standard for a boat) so I'm pretty sure a pressure relief
isn't necessary but can anyone confirm this?
Thanks for any help.
I am replacing the water heater in my boat. The new one is an
"Ariston BLU EVO RS 10U BM EU", it's this one:-
https://www.amazon.fr/dp/B08HZXYYS3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
The installtion instructions come in lots of languages, including
English. I've installed very similar ones in the UK so I know the
basics.
On 03/04/2025 11:20, Chris Green wrote:
I am replacing the water heater in my boat. The new one is an
"Ariston BLU EVO RS 10U BM EU", it's this one:-
https://www.amazon.fr/dp/B08HZXYYS3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
The installtion instructions come in lots of languages, including
English. I've installed very similar ones in the UK so I know the
basics.
However the instructions don't say whether a 'pressure relief' device
is mandatory, they just say "Some countries may require the use of hydraulic special safety devices". It hasn't been supplied with one
and the similar heaters I have installed in the UK don't have one,
they just specifiy how much inlet pipe there must be before a tap
(i.e. space for expansion back down the pipe).
I will be installing with flexible reinforced PVC on the inlet side
(pretty standard for a boat) so I'm pretty sure a pressure relief
isn't necessary but can anyone confirm this?
Thanks for any help.
From the installation manual at:
https://library.ariston.co.uk/document/download/65189033/b0231-aad72-4fa53-0dcfb-8b4b3-c76ad-60572-bea36
When water is heated it expands, in a small unvented water heater of
this type the expansion can normally be accommodated back into the cold
water mains (not model 30L).
Where this is not possible the installer will need to fit a set of cold
water controls.
Note: If a valve i.e. a non return valve, water meter, pressure reducing valve or any type of valve or fitting that acts as a non return valve is installed on the cold water mains, this will prevent expansion.
Therefore it will be necessary to install an expansion vessel (see pages
10 figs 2 & 3).
Note: If in doubt always install a pressure reducing valve (limited to 3.5bar) and expansion vessel.
On 03/04/2025 11:20, Chris Green wrote:
I am replacing the water heater in my boat. The new one is an
"Ariston BLU EVO RS 10U BM EU", it's this one:-
https://www.amazon.fr/dp/B08HZXYYS3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
The installtion instructions come in lots of languages, including
English. I've installed very similar ones in the UK so I know the
basics.
Anything for the UK market, and has a water volume of under 15 litres,
should be self contained, and have all relevant safety devices fitted internally.
Above 15 litres is subject to the G3 Building Regualtions notification,
and should only be fitted by a competent person who has passed the G3
course.
Alan Lee <[email protected]> wrote:
On 03/04/2025 11:20, Chris Green wrote:
I am replacing the water heater in my boat. The new one is an
"Ariston BLU EVO RS 10U BM EU", it's this one:-
https://www.amazon.fr/dp/B08HZXYYS3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 >>>
The installtion instructions come in lots of languages, including
English. I've installed very similar ones in the UK so I know the
basics.
Anything for the UK market, and has a water volume of under 15 litres,
should be self contained, and have all relevant safety devices fitted
internally.
Above 15 litres is subject to the G3 Building Regualtions notification,
and should only be fitted by a competent person who has passed the G3
course.
Ah, thank you, this is under 15 litres so should be 'self contained'.
Fredxx <[email protected]d> wrote:
On 03/04/2025 11:20, Chris Green wrote:
I am replacing the water heater in my boat. The new one is an
"Ariston BLU EVO RS 10U BM EU", it's this one:-
https://www.amazon.fr/dp/B08HZXYYS3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
The installtion instructions come in lots of languages, including
English. I've installed very similar ones in the UK so I know the
basics.
However the instructions don't say whether a 'pressure relief' device
is mandatory, they just say "Some countries may require the use of
hydraulic special safety devices". It hasn't been supplied with one
and the similar heaters I have installed in the UK don't have one,
they just specifiy how much inlet pipe there must be before a tap
(i.e. space for expansion back down the pipe).
I will be installing with flexible reinforced PVC on the inlet side
(pretty standard for a boat) so I'm pretty sure a pressure relief
isn't necessary but can anyone confirm this?
Thanks for any help.
From the installation manual at:
https://library.ariston.co.uk/document/download/65189033/b0231-aad72-4fa53-0dcfb-8b4b3-c76ad-60572-bea36
When water is heated it expands, in a small unvented water heater of
this type the expansion can normally be accommodated back into the cold
water mains (not model 30L).
Where this is not possible the installer will need to fit a set of cold
water controls.
Note: If a valve i.e. a non return valve, water meter, pressure reducing
valve or any type of valve or fitting that acts as a non return valve is
installed on the cold water mains, this will prevent expansion.
Therefore it will be necessary to install an expansion vessel (see pages
10 figs 2 & 3).
Note: If in doubt always install a pressure reducing valve (limited to
3.5bar) and expansion vessel.
None of which addresses my question, is a pressure relief valve needed?
This is not an expansion vessel or a pressure reduction valve.
On 03/04/2025 17:06, Chris Green wrote:
Fredxx <[email protected]d> wrote:
On 03/04/2025 11:20, Chris Green wrote:
I am replacing the water heater in my boat. The new one is an
"Ariston BLU EVO RS 10U BM EU", it's this one:-
https://www.amazon.fr/dp/B08HZXYYS3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
The installtion instructions come in lots of languages, including
English. I've installed very similar ones in the UK so I know the
basics.
However the instructions don't say whether a 'pressure relief' device
is mandatory, they just say "Some countries may require the use of
hydraulic special safety devices". It hasn't been supplied with one
and the similar heaters I have installed in the UK don't have one,
they just specifiy how much inlet pipe there must be before a tap
(i.e. space for expansion back down the pipe).
I will be installing with flexible reinforced PVC on the inlet side
(pretty standard for a boat) so I'm pretty sure a pressure relief
isn't necessary but can anyone confirm this?
Thanks for any help.
From the installation manual at:
https://library.ariston.co.uk/document/download/65189033/b0231-aad72-4fa53-0dcfb-8b4b3-c76ad-60572-bea36
When water is heated it expands, in a small unvented water heater of
this type the expansion can normally be accommodated back into the cold
water mains (not model 30L).
Where this is not possible the installer will need to fit a set of cold
water controls.
Note: If a valve i.e. a non return valve, water meter, pressure reducing >> valve or any type of valve or fitting that acts as a non return valve is >> installed on the cold water mains, this will prevent expansion.
Therefore it will be necessary to install an expansion vessel (see pages >> 10 figs 2 & 3).
Note: If in doubt always install a pressure reducing valve (limited to
3.5bar) and expansion vessel.
None of which addresses my question, is a pressure relief valve needed?
This is not an expansion vessel or a pressure reduction valve.
It does address your question by saying that expansion can either be
absorbed by pipework under certain conditions or using an expansion vessel.
I can assure you I never said your unvented heater was an expansion
vessel and don't understand the basis of your post. You might consider getting a professional in if you believe the installation instructions
don't recommend the use of an expansion vessel or a pressure reduction
valve.
If a pressure relief valve was recommended we can be certain the manufacturers would have specified one in their instructions.
Chris Green <[email protected]> wrote:
Alan Lee <[email protected]> wrote:
On 03/04/2025 11:20, Chris Green wrote:
I am replacing the water heater in my boat. The new one is an
"Ariston BLU EVO RS 10U BM EU", it's this one:-
https://www.amazon.fr/dp/B08HZXYYS3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
The installtion instructions come in lots of languages, including
English. I've installed very similar ones in the UK so I know the
basics.
Anything for the UK market, and has a water volume of under 15 litres,
should be self contained, and have all relevant safety devices fitted
internally.
Above 15 litres is subject to the G3 Building Regualtions notification,
and should only be fitted by a competent person who has passed the G3
course.
Ah, thank you, this is under 15 litres so should be 'self contained'.
Unlike this larger one which sunk the boat. <https://assets.publishing.service.gov.uk/media/547c714ced915d4c100000f3/fleur-de-lys.pdf>
Marland <[email protected]> wrote:
Chris Green <[email protected]> wrote:Coo! :-), or maybe :-(, at least all those on board were rescued OK.
Alan Lee <[email protected]> wrote:
On 03/04/2025 11:20, Chris Green wrote:
I am replacing the water heater in my boat. The new one is an
"Ariston BLU EVO RS 10U BM EU", it's this one:-
https://www.amazon.fr/dp/B08HZXYYS3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
The installtion instructions come in lots of languages, including
English. I've installed very similar ones in the UK so I know the
basics.
Anything for the UK market, and has a water volume of under 15 litres, >>>> should be self contained, and have all relevant safety devices fitted
internally.
Above 15 litres is subject to the G3 Building Regualtions notification, >>>> and should only be fitted by a competent person who has passed the G3
course.
Ah, thank you, this is under 15 litres so should be 'self contained'.
Unlike this larger one which sunk the boat.
<https://assets.publishing.service.gov.uk/media/547c714ced915d4c100000f3/fleur-de-lys.pdf>
It's not that much bigger than our boat, 17m as opposed to 11m,
however the hot water system was 120 litres as opposed to our puny 10
litre one. No wonder there was a big bang!
Still, I think I want to be on the safe side with ours. The old (also
10 litre) under sink water heater had started leaking so needed to be replaced and the Ariston seemed the closest match. I can simply use
the pressure relief valve from the old system I think, that will be
fairly easy to do.
On 2025-04-04 08:07, Chris Green wrote:
Marland <[email protected]> wrote:
Chris Green <[email protected]> wrote:Coo! :-), or maybe :-(, at least all those on board were rescued OK.
Alan Lee <[email protected]> wrote:
On 03/04/2025 11:20, Chris Green wrote:
I am replacing the water heater in my boat. The new one is an
"Ariston BLU EVO RS 10U BM EU", it's this one:-
https://www.amazon.fr/dp/B08HZXYYS3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
The installtion instructions come in lots of languages, including
English. I've installed very similar ones in the UK so I know the >>>>> basics.
Anything for the UK market, and has a water volume of under 15 litres, >>>> should be self contained, and have all relevant safety devices fitted >>>> internally.
Above 15 litres is subject to the G3 Building Regualtions notification, >>>> and should only be fitted by a competent person who has passed the G3 >>>> course.
Ah, thank you, this is under 15 litres so should be 'self contained'.
Unlike this larger one which sunk the boat.
<https://assets.publishing.service.gov.uk/media/547c714ced915d4c100000f3/fleur-de-lys.pdf>
It's not that much bigger than our boat, 17m as opposed to 11m,
however the hot water system was 120 litres as opposed to our puny 10
litre one. No wonder there was a big bang!
Still, I think I want to be on the safe side with ours. The old (also
10 litre) under sink water heater had started leaking so needed to be replaced and the Ariston seemed the closest match. I can simply use
the pressure relief valve from the old system I think, that will be
fairly easy to do.
What is feeding it with cold water? Is this the boat's water pump? If so
that presumably has no possibility of backwards flow to accept
expansion. Boats sometimes have an accumulator on the output of the
water pump to prevent rapid cycling and random pulsing when not being
used due to slight leakage. That would presumably accept considerable expansion?
Fredxx <[email protected]d> wrote:
On 03/04/2025 17:06, Chris Green wrote:But that's the whole problem, they don't. As I quoted before all they
Fredxx <[email protected]d> wrote:
On 03/04/2025 11:20, Chris Green wrote:
I am replacing the water heater in my boat. The new one is an
"Ariston BLU EVO RS 10U BM EU", it's this one:-
https://www.amazon.fr/dp/B08HZXYYS3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
The installtion instructions come in lots of languages, including
English. I've installed very similar ones in the UK so I know the
basics.
However the instructions don't say whether a 'pressure relief' device >>>>> is mandatory, they just say "Some countries may require the use of
hydraulic special safety devices". It hasn't been supplied with one >>>>> and the similar heaters I have installed in the UK don't have one,
they just specifiy how much inlet pipe there must be before a tap
(i.e. space for expansion back down the pipe).
I will be installing with flexible reinforced PVC on the inlet side
(pretty standard for a boat) so I'm pretty sure a pressure relief
isn't necessary but can anyone confirm this?
Thanks for any help.
From the installation manual at:
https://library.ariston.co.uk/document/download/65189033/b0231-aad72-4fa53-0dcfb-8b4b3-c76ad-60572-bea36
When water is heated it expands, in a small unvented water heater of
this type the expansion can normally be accommodated back into the cold >>>> water mains (not model 30L).
Where this is not possible the installer will need to fit a set of cold >>>> water controls.
Note: If a valve i.e. a non return valve, water meter, pressure reducing >>>> valve or any type of valve or fitting that acts as a non return valve is >>>> installed on the cold water mains, this will prevent expansion.
Therefore it will be necessary to install an expansion vessel (see pages >>>> 10 figs 2 & 3).
Note: If in doubt always install a pressure reducing valve (limited to >>>> 3.5bar) and expansion vessel.
None of which addresses my question, is a pressure relief valve needed?
This is not an expansion vessel or a pressure reduction valve.
It does address your question by saying that expansion can either be
absorbed by pipework under certain conditions or using an expansion vessel. >>
I can assure you I never said your unvented heater was an expansion
vessel and don't understand the basis of your post. You might consider
getting a professional in if you believe the installation instructions
don't recommend the use of an expansion vessel or a pressure reduction
valve.
If a pressure relief valve was recommended we can be certain the
manufacturers would have specified one in their instructions.
say is:-
Some countries may require the use of hydraulic special safety
devices: the installer must check the suitability of the safety
device he tends to us.
I am happy that I have enough expansion available in the incoming cold pipework but there isn't a definitive yes/no requirement for the
pressure relief.
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