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M. Filling the GT Boiler with Water
Once all piping connections are complete, flush about 20 gallons of water into the float stack and
drain, repeating until it comes out clean. Close drain valve and pour Nature’s Comfort boiler
treatment in –
required for warranty
. Fill the boiler with a hose through the float stack or if you
have installed a fill line, open the valve and allow it to fill, stopping once the float starts to rise. Use
water that is softened and has low iron content if possible for maximum boiler and pump life.
Do not start circulation pump until boiler is FULL and the impeller and bearings have been
primed!
After filling, remove the top screw on the pump until a steady stream of water flows and all
air has been purged. Being a wet-rotor unit, if the pump runs dry at all, it will seize up as the
bearings rely on lubrication from the water.
See maintenance section for full details on pump
operation and care.
During the first heating cycle the water might expand and overflow. This is normal and will occur
anytime too much water has been added. Open the drain valve to keep the float indicator at the
bottom of the rubber cap. Any higher than this and hot water may push the float out and also cause
scalding water to spill out. (Over-fill when boiler is shut off and not in use)
N. Float Level
After priming and starting the circulation pump and bleeding the heat exchanger (see next section),
let the boiler heat up and run for 24 hours then top off the water if needed. The ideal water level is
at the beginning of a heating cycle for the level indicator to be at the bottom of the rubber cap. The
water level will rise and fall during operation as water expands and contracts with temperature
changes. Be sure to keep the boiler full of treated water at all times including through the summer
as this will keep the boiler free from corrosion and when in use, from overheating causing
circulation pump failure.
O. Bleeding the Heat Exchangers
With the pump running (prime and flush bearings first!), simply close a valve on the return side, hold
for 1 second then open quickly. Repeat the procedure four times or until you cannot hear air rushing
through the line.
III. Heating Domestic Water, Pools and Spa’s
A. Sidearm or Plate Heat Exchanger For Domestic Hot Water
For a sidearm heat exchanger, the hot line from boiler must first go to the top side port. This creates
twice the domestic water flow through the sidearm as opposed to coming in at the bottom side port.
For the fastest recovery, install a small circulation pump on the domestic side that is controlled by a
strap-on thermostat or thermal snap disc placed on bottom line on the domestic side. Hookups to
the domestic side must be connected to the drain and pressure relief ports.
You cannot use a
sidearm if the pressure relief port is on top of the water heater tank.
The domestic side will not
thermal siphon properly and will frequently air lock as well.
Make sure to keep drain & pressure relief in service & purge all air from piping and sidearm or it will
air lock.
The plate HX drawing shown is for a pre-heater setup. Leave utility energy on for this to maintain
the water temperature. As water is used it will then be heated by the plate HX for unlimited hot
water. You may also use a plate HX to bypass the water heater entirely for on-demand operation.
Always use a mixing valve to prevent scalding water temperatures.
Summary of Contents for GT-6000
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