Replacement Parts List

71
HS-300D-PL
TROUBLESHOOTING HYDRONIC SYSTEM PROBLEMS (CONT.)
VALVE SYSTEM TROUBLE ANALYSIS GUIDE
COMPLAINT POSSIBLE CAUSE RECOMMENDED ACTION
No circulation
Relief valve opens
Valve drips
Set screw not tight, coupler loose on shaft
Defective relief valve
Compression tank undersized
Waterlogged compression tank
Run-away burner
Fuel valve stuck in open position
Pump not operating
High limit control fails
Defective reducing valve
System operating pressure too high
Dirt on seal
Tighten set screw in shaft recess
Replace
Check for proper size - replace
Install air control system or drain tank
Check controls
Check valve
Check pump
Check control
Clean or replace
Check static pressure and temperature operation
Lift handle rapidly to discharge dirt - still drips - replace
Reducing valve failures
Reducing valve does not
reduce pressure
Relief valve pops - hot or
cold
Valve does not feed
Strainer plugged
Valve seat scaled shut
City pressure too high for valve
Reducing valve sticking in open position
Check if valve is scaled
Clean or replace
Turn adjustment screw all the way down to free - if it doesn’t - replace
Check valve limitation and replace with higher pressure-rated valve.
Check valve, replace if necessary
Flo-control valve
problems-
Gravity circulation
Pulsating action
Zone valves will not
operate (see note below)
Dirt on seat
Stem not turned down all the way
Valve body not installed in a horizontal position
Air in upper part of valve body
Thermostat not working properly
Power pill burned out
Sticking seal assembly valve will not seal
Take cover off and wipe seat
Turn handle on stem all the way and seat
If in a vertical position, change to horizontal, use straight or angle valve
Open cover and vent
Check thermostat
Check & replace - check electrical connections
Check and clean stem and seat for build-up of mineral scale
Note: If valve does not operate, install in a manual full open or partial position to prevent freeze-up.
MISCELLANEOUS SYSTEM PROBLEMS
COMPLAINT POSSIBLE CAUSE RECOMMENDED ACTION
Insufficient heat in one or
more zones
Air binding
Clogged zone piping
Defective zone valve
Unbalanced circuits
Undersized radiation
Broken coupler on pump
Motor burn-out
Power off
Install air control
Locate and remove obstruction
Repair or replace
Balance
Add radiation or more insulation - increase water temperature
Check alignment of shafts - replace sagging motor mounts
Check pump motor
Check electrical connections - power source
Overheating - cold or
mild weather
Gravity circulation
Defective flo-control valve
Zone valve stuck in open position
Thermostat not operating
Flo-control valve stem in open position
Fuel valve stuck in open position
Controls not operating properly
Install flo-control valve
Clean or repair or replace
Check - repair or replace
Check - replace
Close valve
Check - replace if needed
Check
Pounding or
waterhammer
Lack of system pressure
Over-sized compression tank
Excessive boiler temperature
Pumping into the boiler using high head pumps
Use of solenoid valves
Check if static pressure is correct for system
See note below
Check to see if water is circulating through boiler - stuck fuel valve
(1) Increase static pressure above pump head if possible.
(2) Move pump to pump away from boiler and discharge into system.
Do not use on hydronic systems.
Crackling sound Boiler full of lime (mineral compounds) Clean and flush
Note: If a compression tank is so large that system pressure does not build-up in the proper range with temperature increase, boiling may occur in piping or radiation at the
high point of the system, particularly when pumping into the boiler.
For additional hydronic system troubleshooting information, contact your local Bell & Gossett Representative.