Installation Instructions Strebel Q-boiler range
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6.3
Underfloor heating system (plastic pipes)
When connecting or using an underfloor heating system, designed with plastic pipes, or
plastic pipes are used elsewhere in the installation,one should ensure that the plastic
pipes used comply with the DIN 4726/4729 standard. It is set out in this standard that
the pipes may not have oxygen permeability higher than 0.1 g/m³.d at 40°C. If the
system does not comply with this DIN standard, the underfloor heating component will
have to be separated from the central heating appliance by means of a plate
exchanger.
No recourse can be made to the terms of the warranty in the event of failure
to observe the regulations pertaining to plastic underfloor heating pipes.
6.4
Gas connection
The appliance pipe is fitted with an internal thread, into which the tail piece of the gas
tap can be screwed.
The gas supply must comply to the current Gas Safety Regulations.
The connection to the appliance must include a suitable method of disconnection and a
gas control cock must be installed adjacent to the appliance for isolation purposes. The
nominal inlet working gas pressure measured at the appliance should be 20 mbar for Nat
gas (G20).
Make sure that the gas pipe work does not contain dirt, particularly with new
pipes.
When the boiler has to be converted from natural gas to LPG, STREBEL provides
special kits for this purpose. Special instructions are supplied with the kit.
Always check the installation of all of the parts through which gas flows
(using leak-search spray)
6.5
Hot water supply
Connection of the drinking water installation should be done according to the national
water laws.
The sanitary water pipes can be connected to the installation by means of compression
fittings. The cold water inlet on the Combi boilers must be provided with the following
(counted in the water flow direction):
Dosing valve (supplied), Safety group (consisting of an isolation valve, non-return valve
and expansion valve), Expansion vessel 6bar (potable water, blue).
A dosing valve must be fitted in the cold water pipe. The dosing valve ensures that a
quantity of water is supplied which has a guaranteed outlet temperature of 60°C
(assuming a cold water temperature of 10°C). The quantity of water is virtually
unaffected by the water pressure.
With a water pressure lower than 1.5 bar it is advisable to remove the inside mechanism
of the dosing valve.
