English (GB)
13
7. Universal-head pumps
7.1 General description
Automatic universal-head shower pumps are designed to operate
automatically in installations where the shower outlets are above
the level of the cold-water storage tank.
Shower pumps, types STN, SSN, STR2 CN and SSR2 CN,
feature independent pressure and flow controls, with built-in non-
return valves and stainless-steel expansion tanks in each pump
end. This system ensures complete hot- and cold-water system
isolation with stable control over a very wide flow range.
Fig. 30
Definition of universal-head pumps
7.2 Dry-running protection
STN, SSN, STR2 CN and SSR2 CN universal-head pumps
feature dry-running protection to avoid damage to seals caused
by water starvation. This condition is possible if the water supply
fails, for instance if the water storage is insufficient or the pump
strainers are blocked.
If the pump runs for 60 seconds with an insufficient water supply,
the pump will stop and "lock out".
Fig. 31
Dry-running protection
Resetting the "lock out"
To reset the pump, switch off the power supply for ten seconds.
Fig. 32
Resetting dry-running protection
When the power supply is switched on again, the pump will run
for a few seconds to recharge the tanks. If it continues to run and
there is no demand, this would indicate that one of the following
situations is still present:
• No water in the system.
• Blocked strainer.
• Air which has not yet cleared.
7.3 Connecting the pump
• Follow general instructions in section
4. Installation
.
• Minimum head of water to supply the pump can be found on
the nameplate.
• Maximum static head of 8 metres, i.e. the highest point of the
system must be less than 8 metres above the pump. See fig.
33.
Fig. 33
Maximum static head
• Connect the pump side with the larger expansion tank to cold
water and the pump side with the smaller expansion tank to
hot water.
Fig. 34
Expansion tanks
7.4 Operating instructions
Taps and valves used on the "pressure system" must be fully
turned off when not in use to avoid that the pump runs
reciprocating on and off.
7.5 Installation options
Lavatory cisterns
If the pump is to supply a lavatory cistern, take the precautions
below to avoid frequent starting and stopping of the pump due to
low flow rates.
If possible, best practice is to supply the cistern from the mains
water supply. If this is not possible, we recommend a "Torbeck" or
equilibrium valve. If either of these are not possible, the following
instructions should be followed:
• A: The pump is supplied with two expansion or pressure tanks.
They have capacities of 500 ml and 300 ml.
The larger tank must be used on the cold side of the pump.
• B: The cistern-filling pipe must be as free-flowing as possible
with all flow restrictors removed.
It is possible to change the tanks from one side of the pump to
the other. When doing so, take care to ensure that none of the
fibre washers are lost.
Washer dryers
• Only brass pumps must be used for these applications.
T
M
05
73
1
3
46
1
4
TM
05 731
4 091
3
T
M
05
73
15
09
13
Continued dry running will lead to overheating of the
shaft seals and eventually to a water leak.
> 227 litres
(50 gallons)
60 sec.
ON
OFF
I
/ON
0/OFF
10 sec.
RESET
=
TM
05
73
10
09
13
TM
0
5
7
314
0
913
Max. 8 m
Hot-water
expansion tank
Cold-water
expansion tank
Summary of Contents for SSN
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