MS10-11C Issue 4d
14
Plumbing Advice
The eVolution 26 Stove differs from normal boiler stoves in the fact that it can be installed
on an open vented or sealed heating system. When installing the appliance on a sealed
system, it is necessary to install added safety features which allow the stove to be installed
safely. Our “SCWS Kit” can be purchased separately which contains the main valves
required.
DESCRIPTION OF SAFETY COLD WATER SYSTEM KIT
This is the minimum set of valves required for safe operation on a sealed system.
WATTS STS20 – Thermal discharge Valve
The STS20 prevents the boiler reaching
100°C. This works by transferring the heat in
the boiler away through a secondary quench
coil situated inside the boiler. The quench coil
is activated by a thermal safety valve (Watts
STS20) which activates at 97°C. The thermal
safety valve needs to be connected to mains
water and drained suitably through an outside
wall, in accordance with G3 regulations.
The Thermal Safety Valve needs to be connected to a mains water supply and then to the
quench coil in the boiler. Both openings are ¾ inch female connections. There should be a
minimum pressure of 1.5 bar mains water supply to the STS20. The maximum operating
pressure is 8 bar.
IF YOU CANNOT GUARANTEE A SUITABLE WORKING PRESSURE THEN THE
APPLIANCE SHOULD NOT BE INSTALLED
The discharge from the safety coil needs to be
discharged through an outside wall and terminated at
a low level within a 100mm through a metal pipe that
naturally drains. The discharge pipe should be in
accordance with G3 regulations. The thermal safety
valve probe needs to be inserted into the tube and ½
inch tapping in the rear of the boiler.
To ensure correct operation of the thermal safety drain over the
long-term, periodic drainage of the valve is required (at least once
a year); to perform such operation, press the red discharge
button located at the top of the valve head. Such operation allows
cleaning the seal seat where foreign particles build up. After a
certain number of periodic cleaning operations, it is advisable to
replace the valve plug which is supplied as spare part.
