Combi Thermostatic Mixing Valve; Combi &Expansion Relief - GAH S40/65 User Manual

2-3 Combistream and Combi 65 Thermostatic Mixing Valve
Fig. 2-3a Combistream Mixing Valve
2-4 Combistream and Combi 65 Expansion Relief
Note
Either the Tundish or discharge pipe must
remain in view, do not box in or cover up.
AIR BREAK
DISCHARGE PIPE
Fig. 2-4a Tundish
Note
For more information see 6-2.12.
3
2
4
40
60
20
5
1
80
0
6
0
bar psi
The Mixing Valve will be positioned outside the Boiler case and may be in a different
location than the Boiler. This valve mixes hot water from the Boiler with cold water to
provide hot water of a constant temperature at the taps.
The recommended maximum hot water temperature at the taps is 65ºC.
The recommended setting of the valve is between No.4 and 7 (49º to 63ºC).
The Mixing Valve is factory set to the following approximate mixed outlet temperatures:-
Knob Position Min
Output Temp. ºC 27º
2-4.1 Tundish
The Combi boiler's hot water system has two TPR valves, one for the hot water storage
cylinder and one for the incoming cold supply. In the event of pressure within the hot
water or incoming cold supply becoming too high, either of the TPR valves will vent.
A Tundish should be fitted and located in the same space or compartment as the hot
water storage cylinder. This device provides an air break when pressure is being vented.
When pressure is being vented water/steam will be evident at the Tundish and from the
discharge pipe of the Tundish.
Cold water will normally only discharge when there is an increase in pressure caused by
loss of air pressure in the Accumulator.
In the event of water/steam being seen at the discharge pipe or Tundish, do the
following:-
1. Turn ON a hot and cold tap to relieve the pressure.
2. Turn OFF the Heating System.
3. Investigate possible cause for high pressure e.g.:-
i Hot Water Thermostat Control is set too high.
ii Mains water is not on or fully on.
iii Restriction in hot water pipework.
iv Loss of air pressure in the Accumulator.
4. Contact the installer before restarting the system.
2-4.2 Heating TPR Valve
Combi boilers have a Heating TPR valve mounted on top of the Heat Exchanger and
discharging to the rear of the Boiler. In the event of the pressure within the heating
system becoming too high the TPR valves will vent.
In the event of water/steam being seen at the discharge pipe or Tundish, do the
following:-
1. Check that the radiators are turned on, the heating system should never be operated
with all radiators OFF.
If all radiators are fitted with thermostatic valves, these can all be in a shut condition
if the temperature in the dwelling is sufficient. In this circumstance the heating
system should have a bypass that should be open - see 6-1.3.
2. Turn OFF the Heating System.
3. Investigate possible cause for high pressure e.g.:-
i Boiler Thermostat Control is set too high.
ii Air in the system.
4. Contact the installer before restarting the system.
OPERA OPERATOR CONTROLS OPERA OPERA OPERA TOR CONTROLS TOR CONTROLS TOR CONTROLS TOR CONTROLS
1 2 3 4
32º 38º 44º 49º
2 2 2 2 2
5 6 7 Max
53º 58º 63º 67º
7
2 2 2 2 2