Checking Filling Pressure Of The Expansion Vessel Of The Combination Boiler; Checking Filling Pressure Of The Expansion Vessel Of The Shift Load Storage Tank; Re-Commissioning The Combination Boiler - Vaillant ecoTEC plus 937 Instructions And Maintenance Instructions

7 Inspection and maintenance
• Isolate the unit from the electric mains in the appart-
ment as described in 8.2.
• Close the cold water stop valve on the inlet combina-
tion (see Fig. 7.10) and drain the unit from the hot
water side.
• Release the fitting (1) of the cold water inlet.
• Release the fitting (3) on the connector (2).
h Note
The fitting (3) is located above the elbow (2)
and is not shown in Fig. 7.10.
• Remove the connector (2) from the chassis.
• Flush the connector out under flowing water in the
opposite direction to normal flow.
• Re-fit the connector with the cleaned strainer.
• Fit the pipe elbows of the shift load storage tank and
the cold water feed back in position.
• Always use new seals.
7.5 Checking filling pressure of the expansion
vessel of the combination boiler
Fig. 7.11 Checking filling pressure of the expansion vessel of
the combination boiler
Note
h
This check need not be performed every year –
a check every three years is sufficient.
• Turn the stop valvess of the central heating off.
• Release the pressure from the appliance.
• Remove the valve cover from the expansion vessel.
• Check that the internal pressure in the expansion ves-
sel is between 0.75 and 0.9 bar.
44
If the pressure is less than this, the vessel must be
pumped up again using an air pump.
• Refit the valve cover.
• Re-pressurise the combi boiler and the heating system.
7.6 Checking filling pressure of the expansion
vessel of the shift load storage tank
Fig. 7.12 Checking filling pressure of the expansion vessel of
the shift load storage tank
Note
h
1
This check need not be performed every year –
a check every three years is sufficient.
• Close the stop valves of the hot water system.
• Release the pressure from the appliance.
• Release the screw on the top cover of the shift load
storage tank and remove the cover.
The expansion vessel (1) is freely accessible
• Unscrew the seal cap (2) from the expansion vessel.
• Check that the internal pressure of the expansion ves-
sel is approx. 4 bar.
If the pressure is less than this, the vessel must be
pumped up again using an air pump.
• Screw the seal cap (2) back onto the expansion ves-
sel.
• Re-fit the cover.
• Re-pressurise the combi boiler and the hot water sys-
tem.
7.7

Re-commissioning the combination boiler

• Carry out the electrical safety tests.
• Switch on the electrical supply.
• Turn the stop valves of the central heating on.
• Carry out a function check of the combi boiler as de-
scribed earlier.
• Check the gas rate as described earlier.
• Check for water leaks.
• Re-fit the front case. Make sure that the seal is good.
Installation and maintenance instructions ecoTEC plus 0020031552_03
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