Mammoth 2 to 6 Tons: High Efficiency, Superior IAQ Single Circuit Vertical (B-Vintage) - Manual (Page 19)

19
MAMM-WSHP-IOM-1BA (February 2012)
Performance Troubleshooting
Performance
Troubleshooting
Heating Cooling Possible Cause Solution
Insufficient Capacity X X Dirty Filter Replace or clean
Not cooling or heating
properly
X X Reduced or no air flow
Check for dirty air filter and clean or replace, Check fan motor operation
and airflow restriction. External static too high? Check static vs. blower
table
X X Leaky duct work
Check supply and return air temperatures at the unit and at distant duct
registers: If significantly different, duct leaks are present
Unit doesn’t operate in
cooling
X X Low refrigerant charge Check superheat and subcooling
X X
Restricted metering de-
vice
Check superheat and subcooling– replace
X Defective reversing valve Perform RV touch test
X X
Thermostat improperly
located
Check location and for air drafts behind stat
X X Unit undersized
Recheck loads & sizing. Check sensible, cooling load and heat pump ca-
pacity
X X
Scaling in waterside heat
exchanger
Perform scaling check and clean if necessary
X X Inlet water to hot or cold Check load, loop sizing, loop backfill, ground moisture
High head pressure X
Reduced or no air flow in
heating
Check for dirty air filter and clean or replace. Check fan motor operation
and airflow restrictions. External static too high? Check static vs. blower
table
X
Reduced or no water flow
in cooling Check pump operation or valve operation/setting. Check water flow; adjust
to proper flow rate
X Inlet water to hot Check load, loop sizing, loop backfill, ground moisture
X
Air temperature out of
range in heating
Bring return air temp within design parameters
X
Scaling in waterside heat
exchanger
Perform scaling check and clean if necessary
X X Unit overcharged Check superheat and subcooling
X X
Non-condensable in
system
Vacuum system, reweigh in charge
Low suction pressure X
Reduced water flow in
heating Check pump operation or valve operation/setting. Check water flow adjust
to proper flow rate
X
Water temperature out of
range
Bring water temp within design parameters
X
Reduced air flow in cool-
ing
Check for dirty air filter and clean or replace. Check fan motor operation
and airflow restrictions. External static too high? Check static vs. blower
table
X
Air temperature out of
range Too much cold vent air? Bring entering air temp within design
parameters.
X X Insufficient charge Check for refrigerant leaks
Low discharge air
temperature in heating
X To high of air flow Check fan motor speed selection and airflow
X Poor performance See insufficient capacity