Page 56
UNIT HEATER
7.4.2 Removal of Gas Valves - Automatic Ignition
There are two mounting systems used for the automatic ignition gas valves.
i) S.I.T Tandem valves
These are connected to the main gas manifold using a navy union.
Electrical connection is by a plug on the end of a flying lead.
ii) S.I.T Nova automatic gas valves
These are connected to the main gas manifold using the valve manufacturers angled outlet flange.
Electrical connection is by two pre-wired plugs on a flying lead.
The pilot gas valves are supported on the ¼ BSP inlet pipe and the outlet is a 4mm OD compression
fitting. Electrical connection is by a small three pin plug.
To remove gas valves
i) Disconnect the pilot gas pipe at the compression fitting at the pilot gas valve.
ii) Disconnect the union between the gas supply pipe and the gas valve.
iii) Disconnect the electrical plugs to all gas valves.
iv) Disconnect the navy union or valve outlet flange between the gas valve and the burner.
This allows the gas valves to be removed from the heater
Disassemble gas train for automatic ignition
To separate the start and main gas valves hold the main gas valve firmly in a vice and unscrew the pilot
line from the main gas line at the ¼ m & f elbow by ¼ turn. This will allow the pilot or the main gas
valve to be unscrewed from the main gas pipe.
Refitting is a direct reversal of the above.
It is important when refitting gas valves that only a minimum amount of none hardening gas seal is
used on the pipe threads so that excess sealant is not carried into the valve mechanisms.
It is also important that the valves are assembled with the marked gas flow in the correct direction, and
that the "O" ring seals are fitted to the inlet and outlet flanges where appropriate.
See Section 10 for converting between natural gas and L.P.G.
7.4.3 Removal of gas Valves - Manual Ignition.
All manual ignition models use the S.I.T Nova multifunctional valve for main gas and pilot gas control.
Electrical connection is by a plug on flying lead.
There are also ¼" receptacles for the connection of the thermocouple interrupter relay.
To remove gas valves
i) Disconnect the pilot gas pipe at the compression fitting at gas valve pilot port.
ii) Disconnect the union between the gas supply pipe and the gas valve.
iii) Disconnect the electrical plugs to all gas valves.
iv) Unscrew the thermocouple from the valve and pull off the leads to the interrupter relay.
v) Disconnect the outlet flange between the gas valve and the burner.
This allows the gas valves to be removed from the heater.
To Next Page
Loading...
