22
Rev. 05/2020
Maintaining Heat Transfer Fluid HTF in the Bladder and HEATMOR™
1) Keep your bladder valve closed when filling your stove with HTF (approved water and
at least 30% DOWFROST™ HD) but open at all other times. Your bladder should
have a small amount of HTF in it.
2) HEATMOR™ does not recommend the use of in-line fill valves due to the dilution of
the HTF over time.
Low Heat Transfer Fluid (HTF) Condition
If the HTF level is below the bladder port when the HTF heats up, air will enter the bladder
instead of HTF. To remove the air from the bladder, follow the steps below:
1) Close the bladder ball valve.
2) CAREFULLY remove the bladder hose, allowing the bladder to empty its
contents.
3) After bladder is empty of air/HTF, re-attach the bladder hose to the bladder ball
valve and tighten the hose clamp.
4) Connect the water source to the return line leading to the HEATMOR™. Use a
garden hose to add the water to the return line.
5) Refer to
Filling the HEATMOR™ Outdoor Furnace Initially with Heat
Transfer fluid
.
NOTE: Before the furnace is fired up, the furnace is filled with Heat Transfer Fluid (HTF).
While the furnace is filling with water, the bladder is shut off to prevent air from entering
the bladder. When the furnace is freshly filled the HTF temperature is approximately
50 degrees Fahrenheit. When the furnace is full of HTF you will notice HTF coming out
onto the roof from the relief vent pipe. At this point the water should be turned off and
the bladder valve opened. After the furnace is fired up, the HTF temperature will start to
increase. While the HTF temperature rises, the water will expand as it heats up, causing
the excess HTF to go into the bladder. It will go into the bladder because it is the place of
least restriction. This is another reason why we do not fill the bladder initially, too much
HTF in the bladder at cooler temperatures could cause the bladder to overfill at higher
temperatures caused by the expansion of the HTF during temperature rise
ABSOLUTELY NO FIRE IN THE FIREBOX WHEN PERFORMING THIS PROCESS.
DO NOT PERFORM THIS PROCESS WHEN UNIT HTF TEMPERATURE
IS UNSAFE. ALWAYS WEAR PROPER PERSONAL PROTECTIVE
EQUIPMENT WHEN WORKING WITH HTF AND CHEMICALS.