Hydrolevel VXT-24 - Manual (Page 4)

Feed Counter
The VXTʼs built-in feed counter records the number of gallons that enter the boiler during automatic feed cycles or if the FEED
button is pressed.* To determine how much water has been added to the boiler since the last service, the counter should be
checked, recorded, and reset each time the boiler is serviced. The counter reset (DISPLAY RST) button is located in the bot-
tom right corner of the circuit board.
The addition of water to a boiler raises the oxygen level and accumulates lime and other mineral deposits over time. Excessive
feed cycles, resulting from leaks in the system, can cause cast iron boilers to oxidize (rust) internally, significantly reducing the
life of the boiler. Lime and sediment build-up can impede heat transfer causing damage and/or premature failure of the boiler.
Recommended Limits on Make-Up Water
Many factors, such as the water capacity of the boiler, feed water con-
ditions and boiler design can impact the amount of water that can safe-
ly be added to a steam boiler. As a general guideline for late model
boilers, Hydrolevel recommends the monthly limits in the table at the
right for boiler operation during the heating season. If feed amounts
significantly exceed these levels, the system should be checked for
leaks by a qualified technician. Note: Any feed limits provided by the
boiler manufacturer supercede Hydrolevel recommendations. Please
check the boiler manufacturerʼs instructions carefully.
*The VXT Feeder is equipped with an orifice to regulate flow rates over a wide range of
water pressures. The Feed Counter readings are designed to be accurate to ±15% with
water pressures between 20 to 90 PSI.
Service / Maintenance
Clean Strainer: The Feed Valve Strainer should be removed and cleaned annually.
Check Feeder Operation: Feeder operation should be checked annually during boiler servicing to ensure proper operation
and feed amount.
Record and Reset Feed Counter: The feed counter should be checked annually. If the feed amount falls within the recom-
mendations provided in the table above, record this amount on the card provided and press the reset button (DISPLAY RST)
on the bottom right corner of the circuit board. Note: If the feed amount significantly exceeds the recommendations above, the
system should be checked for leaks by a qualified technician.
Diagnostics / Trouble Shooting
A small indicating light in the lower right hand corner of the digital feed counter illuminates whenever the low
water cut-off is calling for a feed. The light remains on for the duration of the call from the cut-off regardless of
the mode the feeder is in (delay, feed or lock-out). The light turns off when the cut-off is satisfied and stops
calling for a feed.
If LOC appears in the digital counter, the safety lockout feature is activated. This feature engages only when the
feeder completes two consecutive feed cycles and the low water cut-off does not re-energized the burner. The
feeder can be reset by briefly interrupting power to the heating system. Important: The following trouble shooting
steps should be taken to determine the cause of the lockout condition before restoring normal operation.
1. If the boiler is overfilled, the low water cut-off is not functioning properly. Using the manufacturerʼs instructions, check the
low water cut-off operation.
2. If the boiler is in low water:
a. Check boiler and return piping for leaks.
b. If no leaks are detected, check to determine if the flow of the feeder is restricted. Check isolation valves around feeder
to ensure they are fully opened. Remove and clean the Feed Valve Strainer.
c. Check the feeder setting to ensure that it is set to feed adequate water in the event of a low water condition.
If ERR appears in the digital counter, more than one or no delay or feed button has been selected. See Step 4
and Step 5 for DELAY and FEED setting instructions.
If the digital counter is flashing, the meter has “rolled over” (exceeded 999) representing an excessive feed
amount for most applications. Check the system thoroughly for leaks. If no leaks are found, check to determine
if the make-up waterline is restricted. Check feed valve strainer for blockage or heavy build-up of debris.
Reset Feed Counter (see above) once problem is resolved.
P.O. Box 1847 • New Haven, CT 06508 • Phone: (203) 776-0473 • FAX: (203) 773-1019 • www.hydrolevel.com
Recommended Make-Up Water Limits
Net IBR Rating Gal/month
BTU/HR Limit
Up to 90,000 6
91,000 - 120,000 8
121,000 - 150,000 10
151,000 - 185,000 12
185,000 & Higher 15
Note: The above limits are based on normal boiler operation during the heat-
ing season. They do not include water added as a result of boiler and/or low
water cut-off maintenance.