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CHAPTER 11
BLADDER ASSEMBLY
Principles
It is best not to have the system water, that is in the water jacket, exposed to the atmosphere. This is because
of system water loss through evaporation. When system water is lost, it must be replenished or soon the
water jacket would be empty. Not only is replenishing lost system water a nuisance, it is also accelerating
the corrosion process throughout the total system, because adding fresh system water is also adding more
corrosion causing minerals.
The challenge is to maintain an airtight system, while at the same time, allowing for the expansion and
contraction of system water as it warms and cools. This is accomplished in a HEATMOR™ design through the
use of a weighed pop off valve and a flexible bladder.
Bladder
Principle of the Bladder
The HEATMOR™ is designed to be a semi-closed system, with a
maximum of pressure buildup (3 psi).
The bladder is a reservoir that accepts the increased volume of water
that results when the water within the water jacket expands as it is
heated. Similarly, when the water within the water jacket cools down,
water is drawn out of the bladder.
Operation of the Bladder
The bladder has a capacity of approximately 25 gallons. Normally, the
bladder should be approximately ¾ full when the water temperature
is at the high water temperature set point. As the furnace cycles, the
water temperature drops 20 degrees Fahrenheit, approximately three
gallons of water will flow from the bladder. If at any time the furnace is
requiring additional water it will use the reserve water in the bladder
before having to be topped up. Note: The pillow bladder black fitting
is a left handed thread.
Filling the Bladder with Water
You should not need to fill your bladder with water. Under normal operating conditions your bladder should fill
with water and release water as needed for expansion and contraction.
Maintenance / Result
To maintain your furnace bladder simply keep the bladder half full of water so the bladder continues to supply
the water jacket with water. If the water level does run low, the possibilities of water boiling and firebox warping
are increased.
Bladder
Summary of Contents for 400-4S
Page 1: ...Outdoor Furnaces TM SAVE THESE INSTRUCTIONS...
Page 10: ...5 HEATMOR Stainless Steel Outdoor Furnace Model 400 4S Chapter 1...
Page 73: ...68...
Page 88: ...83 PROBLEM CAUSE SOLUTION PROCEDURE...
Page 92: ...87 Outdoor Furnaces...
Page 93: ...88 NOTES...
Page 94: ...89 wiring diagram...
Page 95: ...90 Revised Manual on 07 11 12...
