Laars MASCOT FT MFTCW Installation And Operation Instructions Manual page 37

Mascot FT Combination Boiler
SECTION 4. Installation
4.14 Plumbing Guidelines
Closed type Expansion tank
- Apply 1˝ pipe to the expansion tank to allow air within the system for exhausting.
- Pitch any horizontal piping up towards tank 1 inch per 5 feet of piping.
- DO NOT install automatic air vents on closed type expansion tank systems.
Air must remain in the system and return to the tank to provide its air cushion.
- DO NOT use a closed type expansion tank in a system with the Laars Gas Combination Boiler.
(Automatic air vent has been installed on the boiler.)
- If the combination boiler is installed in a closed water supply system, such as one having a backflow
preventer in the cold water supply line, it will control thermal expansion.
˝
Expansion tank
(Diaphragm-type)
Automatic air vent
Air separator
Circulation pump
Check valve
Drain valve
Gate valve
Backflow preventer
Pressure Relief Valve
CH SUPPLY
PRIMARY LOOP
(SPACE HEATING)
PRIMARY/SECONDARY
CONNECTION
SECONDARY LOOP (SPACE HEATING)
DHW INLET
DHW OUTLET
CH RETURN
Do not exceed 12" apart
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