CJ/T 395-2012_English: PDF (CJ/T395-2012)
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Gas-fired heating and hot water condensing combi-boilers
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CJ/T 395-2012
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| Standard ID | CJ/T 395-2012 (CJ/T395-2012) | | Description (Translated English) | Gas-fired heating and hot water condensing combi-boilers | | Sector / Industry | Urban Construction Industry Standard (Recommended) | | Classification of Chinese Standard | P46 | | Classification of International Standard | 91.140 | | Word Count Estimation | 19,112 | | Quoted Standard | GB/T 13611; GB 25034-2010; GB/T 2828.1-2003 | | Adopted Standard | EN 677-1998, MOD | | Drafting Organization | Guangzhou Devotion Domestic Boilers Manufacturing Co., Ltd. | | Administrative Organization | Ministry of Housing and Urban standard technical focal point of city gas | | Regulation (derived from) | Ministry of Housing and Urban Notice No. 1310; industry standard filing Notice 2012 No. 5 (No. 149 overall) | | Summary | This standard specifies the condensing gas furnace heating bath dual purpose (hereinafter referred to as condensing furnaces) the terms and definitions, classifications and models, materials, structures and safety requirements, performance requirements, t |
CJ/T 395-2012
INDUSTRY STANDARD OF THE
PEOPLE'S REPUBLIC OF CHINA
ICS 91.140
P 46
CJ/T 395-2012
Gas-fired Heating and Hot Water
Condensing Combi-boilers
ISSUED ON: FEBRUARY 29, 2012
IMPLEMENTED ON: AUGUST 01, 2012
Issued by: Ministry of Housing and Urban-Rural Development of the People's
Republic of China
CJ/T 395-2012
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 5
4 Classification and Model ... 6
5 Material, Structure and Safety ... 7
6 Requirements ... 8
7 Test Method ... 11
8 Inspection Rules ... 13
9 Marking, Precaution and Instructions ... 15
10 Packing, Transport and Storage ... 16
Appendix A (Informative) Structural changes between this Standard and EN
677:1998 ... 17
Appendix B (Informative) Technical differences between this Standard and
EN 677:1998 and the reasons ... 18
Appendix C (Normative) Correction for the determined efficiency in the low
water temperature test of condensing boilers ... 19
Appendix D (Informative) Clauses number of this Standard that support the
basic requirements in GB 16914-2003 ... 21
CJ/T 395-2012
Gas-fired Heating and Hot Water
Condensing Combi-boilers
1 Scope
This Standard specifies the gas-fired heating and hot water condensing
combi-boilers’ (hereinafter referred to as "condensing boilers") terms and definitions;
classification and model; requirements for material, structure and safety;
performance requirements; test method; inspection rules; marking; precaution and
instruction; packing; transport and storage.
This Standard is applicable to condensing boilers such as -- rated heat input is not
greater than 70kW; maximum heating operating water pressure is not greater than
0.3MPa; the water temperature is not greater than 95°C in the operation; it adopts
the blower atmospheric burner or full premix burner. For the condensing boilers of
which the rated heat input in greater than 70 kW, it may refer to this Standard.
This Standard is applicable to combi-condensing boilers of heating and hot water,
or condensing boilers of heating-only.
This Standard is applicable to the condensing boilers of natural gas, liquefied
petroleum gas, and manufactured gas that comply with those specified in GB/T
13611.
This Standard is not applicable to condensing boilers of the following types:
-- Natural draught flue type, and natural draught balance type;
-- Outdoor type;
-- Volume type;
-- Condensing boilers that adopt two sets of independent combustion systems
respectively for heating and hot water within the same enclosure, including
the boilers with common flue.
2 Normative References
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated
references, the latest edition of the normative document (including any
amendments) applies.
GB/T 13611 Classification and Essential Property of City Gas
GB 25034-2010 Gas-fired Heating and Hot Water Combi-boilers
GB/T 2828.1-2003 Sampling Procedures for Inspection by Attributes - Part 1:
CJ/T 395-2012
Sampling Schemes Indexed by Acceptance Quality Limit (AQL) for Lot-by-lot
Inspection
3 Terms and Definitions
For the purposes of this document, the terms and definitions defined in GB
25034-2010 AND the following terms and definitions apply.
3.1
Condensing gas-fired heating and hot water combi-boilers
The heating and hot water combi-device or heating-only device, in which the water
vapor in the combustion flue gas is partially condensated, and the latent heat that is
released during the condensation process is effectively utilized.
3.2
Reference conditions
The dry gas of which the reference conditions are: temperature is 15°C; absolute
pressure is 101.325 kPa.
The laboratory environment conditions are: temperature is 20°C; air humidity is
70%; absolute pressure is 101.325 kPa.
3.3
Condensate
The liquid that is formed by condensation of flue gas in the heat exchange.
3.4
Rated condensing output
The design heat output, in kW, when the supply- and return-water-temperature of
the condensing boilers are being operated at 50°C/30°C respectively, under the
reference conditions specified in this Standard.
3.5
Max-allowable working temperature
The temperature the materials can withstand over a long period of time, under
working conditions.
3.6
Running for condensing condition
The condition when the condensing boilers are operated such that the supply- and
return-water-temperature is 50°C/30°C respectively, under the reference conditions
CJ/T 395-2012
The condensate produced during the operation of the condensing boilers shall be
discharged after being collected or treated by the neutralizing treatment device. The
condensate after being treated by the neutralizing treatment device shall keep the
pH value between 6.5 and 8.5.
5.3.3 Collection and discharge of condensate
The structure to collect and discharge the condensate shall comply with the
following provisions:
a) It shall be easily installed, disassembled, inspected and cleaned, and difficult
to block;
b) The internal diameter of the condensate discharge system shall be at least
13mm;
c) For the water-sealed condensate collecting device, the water trap has a seal of
at least 25mm at the maximum flue duct length specified by the manufacturer;
d) The condensate collecting device shall be sealed well to avoid the leakage on
the surface;
e) The condensate collecting device shall be able to prevent the leakage of flue
gas during the operation of the condensing boilers;
f) The surfaces in contact with condensates (except provided drains, water traps,
neutralization system and siphons) shall be designed to prevent the
condensate retention.
g) The device to monitor the blocking of the condensate should be arranged;
h) The condensate discharge pipe shall be the standard accessories of the
condensing boilers.
5.4 Device for limiting flue gas system temperature
The temperature limitation of flue gas system of condensing boilers shall comply
with the following provisions:
a) For plastic flue duct, it shall adopt the device to limit the temperature in the flue
gas system; the condensing boilers shall be closed safely before the flue gas
temperature reaches that given by the temperature limiting device;
b) The temperature limiting device shall not be adjustable.
6 Requirements
6.1 General
The performance requirement for the condensing boilers shall comply with all the
requirements in Chapter 6 of GB 25034-2010, except 6.7. And it shall comply with
the following requirements in this Chapter.
CJ/T 395-2012
Under test conditions in 7.6.2:
a) For the boilers without range-rating device, the heating efficiency,
corresponding to rated heat input, shall not be less than (97+lgPn)%.
b) For the boilers with range-rating device, the heat efficiency, corresponding to
maximum heat input, shall not be less than (97+lgPmax)% and that,
corresponding to the arithmetic mean of maximum rated heat input and
minimum rated heat input, shall not be less than (97+lgPa)%.
Note 1: Pn is rated heat output, in kW.
Note 2: Pmax is maximum heat output, in kW.
Note 3: Pa is the arithmetic mean of the maximum rated heat output and the
minimum heat output for the boilers with range-rating device, in kW.
6.6.3 Heating efficiency at Running for condensing condition under part load
Under the test conditions of 7.6.3:
a) For the boilers without range-rating device, the heating efficiency,
corresponding to 30% of rated heat input, shall not be less than (97+lgPn)%;
b) For the boilers with range-rating device, the heating efficiency corresponding
to 30% of arithmetic mean of maximum rated heat input and minimum rated
heat input of heat input shall not be less than (97+lgPa)%.
6.6.4 Heat efficiency of hot water
Under the test conditions of 7.6.4 at rated heat input (maximum heat input for boiler
with adjustable rated heat input), the heat efficiency in hot water mode shall not be
less than 96%.
6.7 Durability of condensing heat exchanger
The heat exchanger and other parts that likely contact with the condensed water
shall be resistant to corrosion. At the test conditions in 7.7, the durability test shall
be carried out and the test results shall comply with the following provisions:
a) After the durability test, the heat efficiency of repeated-test according to 7.6.1
shall meet the requirements of this Standard;
b) The heat exchanger and other parts that likely contact with the condensed
water shall be free from obvious corrosion marks;
c) After the durability test, the heating system water resistance, when tested
according to 7.9 in GB 25034-2010, shall not be increased by 15% of the
original value;
d) After the durability test, The water circuit tightness tests shall be carried out
according to 7.2.3 in GB 25034-2010 to ensure no leakage or deformation is
found.
CJ/T 395-2012
7.3.2 Airtightness of condensate collecting device
After test of 7.3.1, install the longest flue gas pipe specified by the manufacturer;
block the smoke outlet gradually until the boilers are closed and then inspect
whether it complies with 6.3.2.
7.4 Test of device for limiting flue gas system temperature
7.4.1 Test of flue gas temperature
a) Install the condensing boilers according to the specified conditions in 7.1.3 of
GB 25034-2010; supply the reference gas corresponding to the condensing
boilers type at the rated heat input;
b) Make the temperature controller of condensing boilers be useless;
c) Keep the device for limiting flue gas temperature at the working state; escalate
the flue gas temperature by increasing the gas flow or other modes to increase
the temperature (by removal of baffle) until the fire failure. Inspect whether the
requirements in 6.4.1 are followed.
7.4.2 Test of device for limiting flue gas temperature
After the test in 7.4.1, inspect the device for limiting flue gas temperature to comply
with 6.4.2.
7.5 Combustion test
7.5.1 Running for condensing condition
At 50°C/30°C, test the combustion behaviour at the windless condition according to
test methods specified in 7.6 of GB 25034-2010. It shall comply with 6.5.1.
7.5.2 Condensate blockade condition
At the test conditions in 7.2, where the condensate outlet is blocked or the built-in
pump to remove condensate stops after the over 30min of continuous operation of
condensing boilers, the CO concentration in flue gas shall be inspected and shall
comply with 6.5.2 before closure or lockout of the condensing boilers.
7.6 Heat efficiency test
7.6.1 Heating efficiency under rated load
0-2 gas shall be used. For the boilers without range-rating device, the efficiency
shall be determined in the rated heat input; for the boilers with range-rating device,
the efficiency shall be determined at the maximum heat input and the arithmetic
mean of maximum and minimum heat input. Adjust the water flow so that the return
temperature remains at 60°C±1°C, and the temperature difference between the
supply-water and return-water is 20 K± 2 K. The heat efficiency is determined
according to the test methods specified in 7.7.1 in GB 25034-2010. And it shall
comply with 6.6.1.
CJ/T 395-2012
b) The boiler shall be free from detonation and can be regularly ignited with the
stable flame within the adjustment range of gas flow specified by the
manufacturer.
8.1.2 Sampling inspection
8.1.2.1 Sampling scheme
The sampling scheme of condensing boilers shall be carried out by:
a) Batch-by-batch random inspection is carried out according to GB/T 2828.1.
The sampling scheme is determined by the manufacturer. The probability of
acceptance of the selected sampling scheme shall be controlled at 94%~96%;
b) When products fail the random inspection, this batch of products is deemed as
unqualified. This batch of products shall be re-batched after being inspected
one by one.
8.1.2.2 Items for sampling inspection
The items to be inspected include those specified in 8.1.2.2 of GB 25034-2010 and
8.1.1 in this Standard, as well as the following items:
a) Condensate discharge requirements (5.3 and 6.3);
b) Requirements for device for limiting flue gas system temperature (5.4 and 6.4);
c) CO content under condensate outlet blockage condition (6.6.2);
d) Air/gas ratio regulation performance for Q-type boiler (6.5.8.4.3 in GB
25034-2010);
e) Leakage of non-metallic control tubes for Q-type boiler (6.5.8.4.2 in GB
25034-2010).
8.2 Type inspection
8.2.1 General requirements
Type inspection shall be carried out where one of the following conditions occurs.
Mass production and market-sale may be carried out only after the type inspection
is qualified.
a) Trial production and type evaluation of new products;
a) Trial production and type evaluation of products produced by another plant;
b) When there are significant changes of structure, material or process that may
affect the product performance during the formal production;
c) When production is resumed after long-time shutdown;
d) When there is significant difference between exit-factory inspection results
and the last type inspection results;
CJ/T 395-2012
a) The requirements of 9.2 in GB 25034-2010 shall be followed.
b) As for the condensing boilers without neutralization treatment device, the
precaution "Condensate can only be discharged to non-metallic sewage pipe"
shall be indicated on the products.
9.3 Instructions
9.3.1 Technical instructions for the installer
In addition to the installation provisions in 9.3.1 of GB 25034-2010, the installation
instruction shall also comply with the following provisions:
a) The detailed specifications for discharging the flue gas and the condensate;
the minimum slope and slope direction of the discharge pipe for flue duct and
condensate shall be indicated;
b) Measures shall be taken to prevent the condensing boilers from being
discharged at the flue gas system terminal;
c) Where the condensing boilers comply with the requirements of 6.4 for flue gas
temperature, the manufacturer shall specify or supply the flue duct and fittings.
In addition, the manufacturer shall specify that the boilers is not intended to be
connected to flues that are likely to be affected by heat (e.g. plastic duct or
ducts with internal plastic coatings);
d) Declare whether the condensate has been subjected to the neutralization
treatment and the discharge method;
e) Declare limit value for flue gas temperature.
9.3.2 Use and maintenance instructions for the user
In addition to the provisions mentioned in the 9.3.2 of GB 25034-2010, the
instructions shall also comply with the following provisions:
a) In addition to provisions mentioned in the particular specifications for
condensing boilers, the use and maintenance instructions shall include a brief
description of the operation of the condensing boilers.
b) The instructions shall indicate the heat output and heat efficiency at different
working conditions.
c) The instructions shall state that the condensate outlet shall not be modified or
blocked; and it shall include instructions relating to the cleaning, maintenance
and replacement of any condensate neutralization system.
10 Packing, Transport and Storage
The requirements of Chapter 10 in GB 25034-2010 shall be followed.
CJ/T 395-2012
Appendix C
(Normative)
Correction for the determined efficiency in the low water temperature
test of condensing boilers
C.1 The air humidity and return temperature shall be within the following range; and
the determined efficiency in the low water temperature test of condensing boilers
shall be corrected in accordance with the requirements of C.2~C.3:
0≤X≤20 g/kg (reference value for 10g/kg air humidity)
25°C≤T≤35°C (reference value for 30°C return temperature)
C.2 Where the air humidity differs from the reference humidity at the test conditions,
the determined efficiency shall be corrected in accordance with Formula (C.1):
Where,
η1 -- the correction of determined useful efficiency for air humidity deviation from
the standard value, (%);
Xst -- the air humidity under the reference conditions, (g/kg);
Xm -- the air humidity under the test conditions, (g/kg).
C.3 If the return temperature differs from the standard value for the low water
temperature test, the determined efficiency is corrected by Formula (C.2):
Where,
η2 -- the correction of determined useful efficiency for return temperature
deviation from the standard value, (%);
Tm -- the return temperature under test conditions, (°C);
Tst -- the reference value for return temperature for low water temperature test
(30°C).
C.4 The total correction value shall be such corrected by Formula (C.3):
Where,
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