Install Instructions

ManualsBrandsWeil-McLain ManualsBoilersEVG 399 - 333,000 BTU Output Evergreen High Efficiency Condensing Gas Boiler (NG or LP)

Part number 550-100-131/0715

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GAS-FIRED WATER BOILER — Boiler Manual

Expansion tank

Figure 47 and Figure 48 show typical installations of the system expansion

tank. Always locate the air separator and expansion tank as shown in the

suggested piping drawings, beginning on page 41.

Ensure that the expansion tank size will handle boiler and system water

volume and temperature.

Allow 4.6 gallons for Evergreen 220, 7.0 gallons

for Evergreen 299/300 and 6.7 gallons for Evergreen 399. See tank manu-

facturer’s instructions and ratings for details. Additional tanks may be

added to the system if needed to handle the expansion. These tanks may

be installed by connecting to tees in the system piping.

5NDERSIZED EXPANSIONTANKS cause system water to

be lost from the relief valve and makeup water to be added

through the ﬁll valve. Eventual boiler failure can result due

to excessive make-up water addition. Always locate the COLD

WATERlLLCONNECTION at the expansion tank. Never locate

this elsewhere in the system.

$IAPHRAGMORBLADDERTYPETANK

Refer to Figure 47 for suggested piping when using a diaphragm- or

bladder-type expansion tank.

$IAPHRAGMORBLADDERTYPEEXPANSIONTANK — Con-

trol lLLPRESSURE with the tank air charge pressure. Always

check pressure and charge tank with tank removed from

system to be sure reading is accurate. Boiler relief valve is set

for 30 PSIG. Operating pressure of system, after temperature

expansion above cold ﬁll pressure, should not exceed 24 PSIG

to avoid weeping of relief valve.

Install an AUTOMATICAIRVENT on top of the air separator, per separator

manufacturer’s instructions.

#LOSEDTYPEEXPANSIONTANK

DO NOT use a closed-type tank if connecting to a water

heater that is equipped with an automatic air vent.

Figure 48 shows suggested piping when using a closed-type expansion tank,

in which the air is directly in contact with tank water.

Connect piping (½” or ¾”) from the air separator top outlet to the tank

ﬁtting. Slope any horizontal piping a minimum of 1 inch per 5 feet of

horizontal pipe.

Always use a TANKlTTING, such as the B&G Tanktrol or Taco Taco-Trol

(shown). The ﬁtting reduces gravity ﬂow of water in the piping to the tank,

avoids air bubbling through the tank water, and provides the proper ﬁll

height in the tank.

#ORRECTALLLEAKS in the system or tank piping. Leaks allow

air to escape from the system and will cause water-logging

of the tank. This will result in water loss through the boiler

relief valve due to over-pressurization. .%6%2 use an

automatic air vent in a system equipped with a closed-type

expansion tank. The air removed from the system will cause

water-logging of the expansion tank.

#LOSEDTYPE EXPANSIONTANK — Follow tank manu-

facturer’s instructions for lLLINGTHETANK. Typical tank

sizing provides for approximately 12 PSIG when the tank

is ﬁlled to the normal level and system water is cold. Note

that boiler relief valve is set for 30 PSIG. Operating pres-

sure of system, after temperature expansion above cold ﬁll

pressure, should not exceed 24 PSIG to avoid weeping of

relief valve.

&IGURE Piping to diaphragm (or bladder) type

expansion tank

&IGURE Piping to closed -type expansion tank