Checking The Flow Limiter (Only For Gas Condensing Combi Boiler); Checking The Expansion Vessel And System Pressure - Viessmann Vitodens 100-W B1HF Series Installation And Service Instructions Manual

Commissioning, inspection, maintenance

Checking the flow limiter (only for gas condensing combi boiler)

Fig. 38
Flow limiter
Serial no.
(type plate)
7723181
7722712
7544691
7544693
7722696
7722701
7722222
7720292
7723182
7722713
7544692
7544694
7722697
7722702
7722223
7720293
7723183
7722714
7544695
7722703
7722224
7720294

Checking the expansion vessel and system pressure

Note
The expansion vessel can lose some of its charge
pressure over time. When the boiler heats up, the
pressure rises to 2 or 3 bar (0.2 or 0.3 MPa). The
safety valve may also respond and discharge the
excess pressure.
Therefore check the expansion vessel pre-charge
pressure annually.
52
4.
3.
A
2.
Flow rate
l/min
10 (GB)
12
14
16
1. Drain the boiler on the DHW side.
2. Remove the spring clip.
3. Remove the DHW flow sensor.
4. Check flow limiter . Replace in case of exces-
A
sive scaling or damage. Reinsert.
5. Mount DHW flow sensor with new gaskets.
Danger
Risk of electric shock from escaping heating
water or DHW.
Check all water side connections for tight-
ness.
Colour
Light blue
Red
Pink
Blue
Check whether the installed expansion vessel is ade-
quate for the system water volume.
Carry out this test on a cold system.