Caleffi 253 - Handbuch (Seite 2)

Solar Safety Valve - Series 253 GB
General
Safety (pressure relief) valves are made by Caleffi S.p.A. in compliance with the essential safety
requirements laid down by Directive 97/23/CE of the European Parliament and the Council of the
European Union for harmonisation of member States with regard to pressurised equipment.
The instructions given below are in compliance with Article 3.4, Appendix 1 of Directive 97/23/CE and
are supplied with the products when offered for sale on the market.
TÜV Approval
with larger outlet according to TRD 721
VdTUV Standard for Safety Valves SV100 7.7
Function and Use
For sealed solar heating systems using water or water solutions to DIN Standard 4757 Sheet 1 as the carrying fluid, and
using
a diaphragm expansion vessel. The Series 253 diaphragm safety valve is designed exclusively for solar heating
systems. The diaphragm safety valve only opens the discharge when the system pressure exceeds the rated calibration of
the valve. The diaphragm safety valve discharges the heating power of the solar system in the form of hot water and steam.
Technical and Constructional Characteristics
Body and inner assembly:
DIN EN 12165 CW 617N 25364. 1/2” F inlet 1/2” F outlet
Nominal pressure: PN10 25304. 1/2” F inlet 3/4” F outlet
Max. allowable working temperature: 160°C 25305. 3/4” F inlet 1” F outlet
Fluid used: Water/glycol solution, max. 50% Max Power Rating: 25364. 40 kW
PED Category: IV 25304. 50 kW
Calibration: 2,5; 3; 4; 6; 8; 10 bar 25305. 100 kW
Installation
Diaphragm safety valves should be installed vertically, in line with the direction of the arrow. The connecting pipework should
be a maximum of 1 m long without any bends. Filters and other restrictions should be avoided in the connecting pipework to
the solar safety valve. The cross-section of the connecting pipe must be at least equal to the inlet cross- section of the safety
valve. Horizontal connections should be avoided, to prevent the build up of dirt and debris.
These safety valves should be installed in the coldest part of the solar heating system, without interfering with the solar
manifolds, and must be accessible. It is also advisable to install the valves near the solar control station. The diameter of the
discharge pipework must correspond to the valve outlet diameter; the maximum length should not exceed 2 m, and not more
than two bends are permitted. If these maximum values are unavoidably exceeded (2 bends, 2m of piping), the next diameter
up must be selected for the discharge pipework. However, on no account are more than 3 bends and 4 metres of pipework
permitted. If the discharge piping of the safety valve is connected via a tundish, the cross-section of the valve discharge
pipework should be at least double the cross-section of the valve discharge itself.
Water/glycol solutions must be collected in a container of suitable dimensions under the safety valve discharge pipe.
The discharge piping must be installed with a downward slope; the outlet of the pipework must be open and inspectable and
positioned in such a way that nobody is endangered during a discharge.
Commissioning
When commissioning the solar heating system, the system is filled until the calculated pressure value is reached. Accurate
sizing of the expansion vessel is necessary to prevent undesirable discharging of the valve.
The calibration pressure value of the safety valve is marked on the tamper-proof plate on top of the black knob.
Guarantee
These safety valves are produced with the greatest possible precision and, of course, subjected to strict inspection.
However, in the unlikely event of a fault, our guarantee covers material and manufacturing defects. If the tamper-proof plate
is damaged or the valve is found to have been used incorrectly or damaged due to wear and tear, the guarantee will become
invalid. In order to claim against the guarantee, the complete valve must be returned to the manufacturer.
Safety
If these safety valves are not installed, commissioned and maintained correctly in accordance with the instructions
contained in this document, then they may not operate correctly and may endanger the user.
Ensure that all connections are water-tight.
When making hydraulic connections, ensure that the valve body thread is not mechanically overstressed. Breakage
may be caused over time causing water leaks, harmful to property and/or individuals.
Water temperatures higher than 50°C can cause serious burns. When installing these safety valves, make all necessary
arrangements to ensure that such temperatures do not endanger individuals.
Leave these instructions with the User
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