Operating instructions

Relief Valve
Youmust have a reliefvalve on your boiler.Water expands as it is
heated. Ifthere is no place for the water to expand into, water pres-
surewill build up inside the boiler and system. Should this happen,
the ReliefValvewill automaticallyopen at a pre-determined pres-
sure. Thiswillrelievethe strain on the boiler and system.Run a pipe
from the reliefvalveoutlet (pipe must be same size as outlet and the
open end must not be threaded) to an open drain, tub or sink, or
other suitable drainage point not subject to freezing. Failure to do so
may causewater damageor injury should reliefvalverelease.
Expansion Tank
In a properly assembled system, the expandingwater flowsinto an
Expansion Tank.Thistank should be ofthe correct size.
Thetank ispartially filledwith air.As the water expandsit compress-
es the air in the tank to form an airpressure cushion. This"spring-
like"cushion serves to maintain correct operating water pressure
regardlessof water temperature. Thisassuresa "fullmeasure" ofwa-
ter, evenin the highest radiation unit of the system. It also prevents
blowingoffof the reliefvalve.
Theair in the tank in the beginning (with systemfilledwith cold wa-
ter) is sufficientfor proper operation. Thetank also servesas a trap
for excessair in the system. Theair would causegurgling in the pipes
and inefficientcirculation in the radiators if left in the system.
It ispossible fora tank to become "waterlogged"(filledwith water).
It can also become overfilledwith air.Thiscan happen after filling
the systemwith newwater.Fittings provided on the tank and in the
line to the tank are for bleedingoff excesswater or air.
When installingthis tank, it is important:
1)That the tank be higher than the boiler top.
2) That the pipe to the tank continuouslyrises up to the tank (so that
air can "bubble"up to it).
Diaphragm Type Expansion Tank
TheDiaphragm Type Expansion Tank (EX-TROL)takes the place
of the conventionalexpansion tank. Carefullyread the instructions
packed with your EX-TROLTankAssembly.The EX-TROLTank
comesto you with a 10-12pounds per square inch air charge.Thisis
the sameas the pressure produced in the systemby the automatic fill
valve.When the systemis firstfilled,the EX-TROLTank will contain
little or no water.
Asthe water is heated its pressure increases.It expands into the EX-
TROLTank,compressingthe air in the tank. Thiscompressed air
cushion permits the water in the systemto expand as the tempera-
ture changes.
Air Eliminating Fitting (Air Purger)
An Air Purger is usedto remove excessairfrom the system. It is in-
stalledin the supplyline. It will help to eliminate airfrom the water
before it reachesthe radiators and bleed offthis air.
Main Air Vent For Down Flow Systems Or Diaphragm Type
Expansion Tank
Beforea system isfilledwith water,there is air in the pipes and
radiation units. Someof itwill be trapped as the systemis filled.It
ispossibleto eliminatemost of this air through the airvents on the
radiation units. A Main Air Vent will speed and simplifythis. It
shouldbe installed on the highest point in the main when allradia-
tion isbelow top of boiler.
Automatic Fill Valve
For safe,efficientoperation, a hot water systemmust be filledwith
water.Adding new water,when needed can be done manually (by
use of a hand valvein the water supplyline). Thisrequires regular at-
tention to the system'sneeds. An Automatic FillValveaccomplishes
this without attention. It is installed in the Supply Lineon hot water
boilers only.TheValveoperates through water pressure differentials.
It does not require an electricalconnection.
Drain Valve
This manual valve provides a means of draining all water from the
boiler and system. It is often installed in the _" Tapping at the bot-
tom of the left boiler section. Or it can be installed in a tee where the
return line enters the boiler.
Water Temperature Control
The water temperature limit control in the relay is adjustable and
may be set as necessary. It may be set as low as 140° F, or as high as
240° E This depends on the type and amount of radiation involved
and weather conditions.
Circulating Pump
EveryForcedHot-Water Systemrequires a Circulating Pump. A
separatepump or zonevalveis required for eachZone, ifyou have
a two or more Zone System.Thispump must havethe capacityto
provide the circulation required by your system.
Thepump does not come pre-installed on the boiler. It must be con-
nected to the circulator harness in the field accordingto the pump
manufacturer's instructions and the wiring diagrams in this manual.