|
|
| 1.
|
What type of domestic instantaneous
gas water heater should I choose? |
| |
|
| Ans: |
Room-sealed
(balanced-flue) gas water heaters are the first choice for new
and replacement installations.
Fresh air for combustion and combustion products are taken from
and discharged directly to outside air (i.e. sealed against
the room), and the heater will not consume or contaminate the
air in the room. |
| |
|
|
 |
| |
In a premises where
a suitable flue aperture has been provided for the installation
of a room-sealed gas water heater to serve a bathroom, then
it is an offence to install any other type of gas water heater
in the premises.
Room-sealed heaters are available in different models including
fanned draught models, and can be installed easily in most situations. |
|
| |
| 2. |
What
types of gas water heater installations are "substandard" and should
not be used? |
| |
|
|
| Ans: |
a. |
Open-Flued (Natural
Draught) Gas Water Heaters |
| |
|
It is now against the law
to install any open-flued (natural draught) gas water heater. |
| |
|
|
| |
b. |
Flueless (Sink) Gas
Water Heaters supplying Bathrooms |
| |
|
It is against the law to install
a flueless (sink) gas water heater for bath or shower purposes. Flueless
(sink) gas water heaters are designed only for kitchen sink use (e.g.
washing dishes intermittently). They are considered dangerous if used
to supply hot water to a bath or shower, because the products of combustion
containing toxic carbon monoxide discharge directly into the room
where the heater is situated, and may build up to dangerous levels.
|
| |
|
|
| |
c. |
Flueless (Outdoor)
Gas Water Heaters installed Indoors |
| |
|
Flueless (outdoor) gas
water heaters are substandard and very dangerous if they are
installed indoors, because large amounts of combustion products
are released directly into the room where the heater is situated.
They are now obsolete in Hong Kong and are not allowed to be
installed. |
|
 |
| |
|
| 3. |
Why
is it unsafe to use a substandard installation? |
| |
|
| Ans: |
The main
danger is from carbon monoxide (CO) poisoning. All gas water
heaters are capable of producing carbon monoxide in their flue
gases, but a substandard installation may suddenly cause high
levels of carbon monoxide to be built up indoors for many reasons.
|
| |
|
|
 |
| |
Carbon monoxide is a
toxic gas. It is a colouress, odourless and tasteless gas, and
its presence is undetectable, therefore being called as "Silent
Killer". As little as 0.4% concentration of carbon monoxide
in the air can cause unconsciousness and death in a few minutes.
A defective gas water heater may be able to produce this amount
in a very short time. |
|
| |
|
