Exchanger will not heat properly

Cause

Temperature control sensor below or too far from heat source.

Solution

Verify control/sensor operation and secure sensor above bottom of exchanger and near work or reinstall coil deeper in tank.

Cause

Valve stuck in open position.

Solution

Test valve operation and repair/replace as required.

Cause

Improperly sized trap causing excessive condensate and time lags in system

Solution

Verify proper trap size and type required for application and replace as required.

Cause

Defective or damaged temperature control sensor on thermostat.

Solution

Consult temperature control trouble-shooting information and repair or replace as required.

Cause

Temperature control probe mounted in air.

Solution

Verify control/sensor operation and secure sensor adjacent to coil.

Cause

Temperature control out of calibration.

Solution

Verify temperature control accuracy by placing known accurate thermometer in same location a control sensor and calibrate as required.

Cause

Heat exchanger too large for application.

Solution

Verify all heating requirements and replace exchanger as required.

Cause

Low steam pressure. (Any pressure below the design rating of the coil significantly reduces the rated output of the exchanger.)

Solution

Measure the available pressure and compare it to the rating on the tag. Check and compare your incoming pressure at the boiler vs. the pressure at the coil. If the difference exceeds 3 psi consider increasing the pipe size or adding insulation. Either add additional coils or replace the coil with a larger one to add more exchanger surface area to increase capacity.

Cause

Temperature control sensor not located properly in tank.

Solution

Place/secure sensor 1/3 of way down in solution (preferably within a thermal well).

Cause

Steam pressure too low for proper operation of standard pilot operated valve.

Solution

Increase steam pressure at the valve or install a direct acting or zero pressure differential valve in its place.

Cause

Coils plumbed in series. (This condition would cause each successive coil to produce less than the rated output while increasing the pressure drop and condensate on the system substantially.)

Solution

Reconnect coils in parallel to an appropriately sized header

Cause

Water hammer damage to internal baffles within grid style coils which allows flow to bypass portions of the exchanger.

Solution

Contact factory for repair install drip trap before steam valve and water hammer arresters in supply line.

Cause

Buildup on coil sheath.

Solution

Inspect and clean coils on a regular basis appropriate to the rate of buildup from the chemistry employed. Check application, as larger/more surface area may be required in most solutions that buildup quickly.

Cause

Improperly sized exchanger.

Solution

Verify heat requirements and replace exchanger as required.

Cause

Coil not fully submersed in fluid being heated.

Solution

Fill tank to submerse coil or correct mounting or plumbing to accommodate low fluid level.

Cause

Inlet/outlet connections reversed on steam coil.

Solution

Verify inlet/outlet per installation instructions and correct connections as required.

Cause

Low temperature feed water supply (for heating). Too high temperature feed water supply for cooling.

Solution

Verify temperature of feed water and correct as required.

Cause

Steam trap installed on inlet side of coil.

Solution

Reconnect stream trap on outlet side of coil.

Cause

Plugged vent hole on steam trap.

Solution

Clean any deposits from trap vent.

Cause

Blocked strainer.

Solution

Clean or replace strainer.

Cause

Undersized supply piping.

Solution

Calculate BTU requirements for tanks and respective flow requirements. Rework or replace coil inlet/outlet tubes to accommodate flow.

Cause

Steam coil operated on water service. Grid style water coils require baffles to direct internal flow. (Note: Coils designed for water service will operate fine in both steam or water applications.)

Solution

Replace coil with one designed for water service.

Cause

Back pressure from condensate return on low-pressure steam systems can prevent outflow of condensate from trap

Solution

Verify that pressure on condensate leg is below pressure on outlet of each individual coil.

Cause

Condensate return line and/or trap above exchanger.

Solution

Do not route condensate return above outlet of exchanger without condensate pump. Trap should be mounted 18" below coil outlet. Correct trap location and condensate piping as required.

Cause

Undersized supply piping.

Solution

Calculate BTU requirements for tanks and respective flow requirements. Rework or replace coil inlet/outlet tubes to accommodate flow.

Cause

Steam coil operated on water service. Grid style water coils require baffles to direct internal flow. (Note: Coils designed for water service will operate fine in both steam or water applications.)

Solution

Replace coil with one designed for water service.

Cause

Undersized supply piping.

Solution

Calculate BTU requirements for tanks and respective flow requirements. Rework or replace coil inlet/outlet tubes to accommodate flow.

Cause

Condensate return line and/or trap above exchanger.

Solution

Do not route condensate return above outlet of exchanger without condensate pump. Trap should be mounted 18" below coil outlet. Correct trap location and condensate piping as required.

Cause

Steam lock on piping between coil and trap.

Solution

Re-plumb trap 18" below exchanger outlet line with as short of horizontal pipe as possible. If problem persists, install steam lock release or trap with integral steam lock release.

Cause

Improperly sized trap.

Solution

Calculate BTU requirement for tank and verify proper trap sizing. Replace as required.

Cause

Multiple coils on single steam trap.

Solution

Each coil must have its own trap for proper operation. Verify operating parameters for each coil and install an appropriately sized trap.

Cause

Improperly sized solenoid valve.

Solution

Evaluate BTU requirement for tank and verify valve Cv rating. Replace valve as required.

Cause

Improper trap style selection.

Solution

Inverted bucket traps work fine on metal coils, however, balanced pressure or thermostatic traps perform better on fluoropolymer exchangers by reducing air binding. Replace traps as required on fluoropolymer coils.

Cause

Condensate return line and/or trap above exchanger.

Solution

Do not route condensate return above outlet of exchanger without condensate pump. Trap should be mounted 18" below coil outlet. Correct trap location and condensate piping as required.

Cause

Condensate line plumbed above exchanger causing back pressure on trap.

Solution

Re-plumb condensate return system or add condensate sump/pump to evacuate condensate.

Cause

Air-bound steam trap. Air in system both insulates and dilutes the steam reducing its temperature and forms a film on the exchanger walls limiting heat transfer.

Solution

Change trap style to one that can vent air from system faster or install a bypass bleed valve to evacuate air in line.

Cause

Unbalanced load/mixed types of coils.

Solution

Multiple coils should be plumbed to a single appropriately sized header and with valves provided to distribute/adjust each output. Combining water coils of different sizes, or non-uniform groupings will cause unbalanced pressure drops on one or more of the coils and inefficiencies.

Cause

Buildup inside exchanger sheath. Caused by particulates or colloidal materials that have accumulated on the coil interior surfaces from the water/steam source.

Solution

Dissolve away all deposits with exchanger with a chemically compatible cleaner. Install a water conditioner and strainer on the water/steam supply.

Cause

Viscous or concentrated solution. Dense or concentrated solutions impede heat flow from the sheath and can reduce performance.

Solution

Increased mixing of the solution near the coil can reduce the problem. Consider installing multiple coils and space them evenly around the tank to enhance heat distribution.

Cause

Kinked or damaged tubes.

Solution

Visually inspect all exchanger tube surfaces for dents, kinks or collapsed tubes. Repair or replace as required. Protect coil from damage with guards or move to protected location.

Cause

Solenoid valve electric operator coil open/burned out.

Solution

Test operator coil by applying rated voltage and replace coil or valve as required.

Cause

Solenoid valve stuck in closed position by deposits.

Solution

Clean/repair valve if possible. Install strainer on inlet supply prior to valve to reduce particulate matter flowing through valve.

Cause

Low pressure. (Many pilot operated solenoid valves require 5 PSIG minimum pressure drop across valve to operate.)

Solution

Increase pressure on supply or replace valve with a zero pressure drop model valve.

Cause

N/O solenoid valve used instead of N/C valve.

Solution

Verify valve operation and replace as required

Cause

Steam/hot water source is blocked by shut off valves.

Solution

Verify that all valves preceding coil are open and supply is available to coil.

Cause

Plugged strainer.

Solution

Open and clean strainer.

Cause

Defective trap or mis-sized trap

Solution

Repair or replace trap.

Cause

Solenoid valve not connected to terminal blocks in control

Solution

Connect as required.

Cause

Solenoid coil voltage does not match power supply

Solution

Replace solenoid valve or coil to match available power.

Cause

Improper wiring/voltage not jumpered to isolated contacts of control.

Solution

Verify wiring with appropriate diagram and correct if necessary.

Cause

Incorrect thermostat settings.

Solution

Verify thermostat settings and switch operation, repair or replace as required.

Cause

Defective temperature control/sensor.

Solution

Verify temperature control operation, repair or replace as required.