Peerless boiler troubleshooting

One needs to know common causes of breakdowns to extend the service life of appliances. The most frequent boilers Peerless malfunctions can be learned from the troubleshooting table provided below. Refer to the table to determine the essence of any malfunction and complexity of the forthcoming repairs. Thus, some minor breakdowns can be removed on one`s own.

Peerless 211A series boiler troubleshooting

ProblemPossible CauseSuggested Remedy
Defective ThermocoupleReplace
Heavy Draft Blowing across RiotRedirect Air Movement or Eliminate
Plugged Pilot OrificeReplace Orifice
Pilot OutageNo GasCheck Manual Pilot Valve Check Main Gas Shut-Off Valve Check Manual Meter Valve Consult Gas Company
Defective Thermopilot ValveReplace
Defective Ignition ControlReplace
No PowerCheck Power Source with Meter Check Fuses
Defective Gas ValveReplace
Defective ThermocoupleReplace
Main Gas Valve Will Not OpenLow Water Level in Boiler or System Causing Low Water Cut-off to Function
Check for Leaks Check Feeder (if Supplied)
(Standard Spark-Ignited Pilot System)Defective Thermopilot ValveReplace
Defective Ignition ControlReplace
High Gas Pressure Switch Open (if Rovided)Check Switch Setting Check Manifold Gas Pressure
Low Gas Ressure Switch Open (if Rovided)Check Switch Setting Check Manifold Gas Pressure
No PowerCheck Power Source with Meter Check Fuses
Defective Gas ValveReplace
Relay Locked Out on SafetyCheck for Pilot Outage
Riot OutRelight Pilot
(May have defective pilot valve or relay)
Main Gas Valve Will Not OpenDefective RelayReplace
(Electronic Standing Riot System)Low Water in Boiler
or System Causing Low Water Cut-off to Function
Check for Leaks Check Feeder (if Supplied)
Defective Thermopilot Valve(s)Replace
Defective Thermocouple(s)Replace
High Gas Ressure Switch Open (if Rovided)Check Switch Setting Check Manifold Gas Pressure
Low Gas Ressure Switch Open (if Rovided)Check Switch Setting Check Inlet Gas Ressure
Bumer(s) Burning with Yellow FlameAir Adjustment Screws Turned in Too FarAdjust Screws Out
Low Gas Pressure in Manifold (Insufficient Air Injection)Adjust Main Gas Pressure Regulator or Check Line Pressure
Burner Ports Partially Closed (Rust, Dirt, Lint, etc.)Replace Burners or Clean Ports
Insufficient Air for CombustionCheck Size of Combustion Air Openings to Room, if Undersized, Correct as Required Check for Negative Pressure in Boiler Room
Oversized Burner OrificeInstall Correct Orifice
High Gas Pressure in ManifoldAdjust Main Gas Pressure Regulator
Gas Spillage from Draft Hood Relief OpeningInsufficient Draft - Chimney Too LowIncrease Height or Add Induced Draft Fan
Insufficient Draft - Chimney Too SmallReplace Chimney or Add Induced Draft Fan
Insufficient Draft - Blockage in Chimney or VentRepair Chimney or Vent
Insufficient Draft - Downdraft Caused by Chimney Location with Respect to Other Buildings, Roofs, etc.Install Chimney Cap
Negative Pressure in Boiler Room (Due to Exhaust Fan or Duct System)Remove Exhaust Fan
or Isolate Fan From Boiler Room
Insufficient Combustion Air OpeningsProvide Correctly Sized Combustion and Ventilation Air Openings
Main Gas Valve Opens But No Gas FlowsManual Valve Closed at Gas TrainOpen Valve
Manual Valve Closed at MeterOpen Valve
Test Firing Valve Closed (if Provided)Open Valve
Water Hammer On Start-UpSags in Steam Piping or not enough PitchCorrect Piping Condition
Concentric reducers causing condensate poolingCorrect Piping
Drip trap failed closedReplace Trap or Trap Element
Dry returns wetted due to new boiler water line higher than old boilerCorrect Piping or Install Feed System and Traps
No drip line on the back side of a back-pitched motorized valveInstall Drip Line and Trap
Water Hammer During Mid-CycleCbgged returns on gravity systemClean or Re-Pipe Return Line(s)
Incorrect near-boiler piping causing wet steam to systemCorrect Piping per Manual
Trap failed open, allowing steam to enter returnsReplace Trap or Trap Element
{Radiator Hammer} Large radiator may be vented too quicklyUse smaller Air Vent or Use Two Small Vents in Place of One Large Vent, One Mounted Higher than the Other
Long nipple at Hartford LoopReplace with Close Nipple
Water leg or back slope in return line to receiver tank, causing water pocketingCorrect Piping
Trap installed at receiver tank, causing water trapping in returnRemove Trap at Tank, Installing Drip Traps and Radiator Traps where Required
Boiler feed pump or condensate pump feed rate too fast, causing spraying into equalizerThrottle Flow Rate
No drip on the inlet side of a forward pitched motorized valveAdd Drip Line and Trap
Uninsulated steam piping, causing excessive condensate loadsInsulate Steam Pipes
Water Hammer on Shut-DownCbse nipple on Hartford too highRepipe 2" to 4" (5cm to 10cm) Below Water Line
Uninsulated steam piping in boiler room, but system piping insulated, causing vacuum condition on shut-downInsulate Steam Pipes
Hammering in the BoilerPoor circulation in the boiler due to sludge accumulationClean and Blowdown the Boiler
No Heat or Poor Heat Distribution in the BuildingMain vents not workingReplace Main Vents, Repiping away from End of Lines if Needed
Drip Traps failed closedReplace Traps or Trap Elements
Radiator traps failed open, allowing pressurization of the returnsReplace Traps or Trap Elements
Water legs or back slope in return lines to receiver tank, preventing air from venting out receiver ventCorrect Piping
Boiler pressure too high, causing air vents to lock up or blowing water loop sealsReduce Operating Pressure
System or Boiler Overfilling or FloodingNew boiler water content smaller than old boilerInstall Boiler Feed System with Receiver Tank Large enough for Condensate
Boiler water feed rate or pump rate too fast causing water level to collapse (due to collapse of steam bubbles in boiler water)Reduce Feed Rate
Foaming, priming or surging due to poor water qualityClean the Boiler
Excessive Water Level BouncePoor water quality, causing foaming and surgingClean the Boiler
Incorrect near-boiler piping, such as undersized or incorrectly placed risersPipe per Manual
Boiler water feed rate or pump rate too fastReduce Feed Rate
Rapid CyclingAir vents or traps not venting air, preventing steam from getting to radiation and pressurizing the air pocketReplace Vents or Traps
Pressure differential on pressure control too closeAdjust Control Differential
Nuisance outages of water level control due to boiler water level bounceSee Excessive Water Level Bounce Above

Peerless CAST 92 boiler troubleshooting

SitutationSuggested Procedure
Nothing happens when the power switch is turned on.1. Check 120VAC power to connection board. Verify power is connected per wiring diagrams.
2. The Power switch light (ON -Position) should illuminate if power is wired correctly.
3. If the Ignition Control is active, but the front panel display is inactive check:
• Cable and cable polarity from the control board to the display.
• Check for 120vac on the primary of the transformer and 24vac on the secondary. If one of the 24vac interlocks has been shorted to ground or the 24vac output is low, the transformer may be damaged or a 24vac circuit may be miswired.
4. The Cast 92 control is equipped with resettable fuses on the power input circuit. Wiring power incorrectly to the unit will cause these fuses to open. Once the incorrect wiring is corrected, the fuses should reset themselves in less than 5 minutes.
The display shows combustion air damper failure.1. If you are not using the combustion air damper then it needs to be disabled in the AUX FUNCTIONS menu.
2. The prove switch for the combustion air damper is not closing. Check to make sure the dampers are being controlled by the output relay you specified when programming for the damper. Also check to make sure the prove switch is working properly.
3. If there is no proving switch, you must put a jumper wire across input connection (USER INTRLK).
4. If these steps have been done and you continue to get the error message, check the sensor TYPE specified in the SENSORS menu. If it is set to NONE, the controller will not recognize the closed circuit. Set the Sensor type to ON/OPT.
The display is displaying ran- dom characters or the control keeps resetting.1. There may exist a grounding problem with the controller or one of the boilers, pumps, contactors or other devices connected to it.
2. If all grounding is correct, there may be an issue with radiated or induced electrical noise (interference). This may be caused by arcing across a contactors contacts when starting a pump motor or a large electrical load. It may also be caused by the ignition transformer being improperly grounded or the spark gap being out of adjustment.
3. Attempt to identify the noise source:
• What is the boiler/controller trying to do at the time of the failure?
• Is the boiler on the same circuit as the noise source? (The boiler should have isolated power.)
• Are shielded sensor wires used? (Ensure the shields are grounded only at the boiler control end.)
• Are any sensors or sensor wires located near a transmitting antenna? (Move sensor)
There are no heating boilers on.Check the settings for OA SETPOINT and OA RESET
• If the outdoor air temperature is above the OA SETPOINT and OA RESET is on, the circulator pump relay will be locked out and the heating boilers will not fire.
• If the water temperature is within the heating band around the setpoint, boilers will not come on.
• The water temperature must fall below the lower band limit to begin firing boilers.
Unable to change the # of Boilers in the BOILERS menu.1. Using the Cast 92 control for multiple boiler operation, the Cast 92 control auto-detects the boilers in the system and adjusts the number of boilers accordingly.
2. If the number of boilers is not being detected properly as the actual number of boilers in the system, check each boiler. There can only be (1) master boiler, but there can be up to 15 member boilers.
3. Make sure only the master boiler has a Header Sensor connected.
4. Verify that each boilers cable is in place.
5. Verify that each boiler has a unique address assigned (ADVANCED SETUP DISTRIB CTRL. LOCAL AD).
The BOILERS menu only indicates one boiler, but there are member boilers connected. The amber light blinks on all of the boilers communication’s jacks.1. Verify that the latest version of firmware is installed on all boilers.
2. All boilers in a system must have the same firmware revision (version).
3. Verify the proper termination is set on the Master and the last Member boiler.
Boilers are detected but then lost and then detected again.
1. The control communications cable may be receiving interference from the blower, ignition, or other form of radiated electrical noise.
2. Termination of the jumpers may not be correct or there is more than one master.
• Ensure that the termination dip switchs are set on the MASTER boiler and only the LAST MEMBER boiler. All of the other member boilers should have their termination dip switches OFF
• There may be two or more MASTER boilers. Ensure that only one header sensor is present and connected to the HEADER input. There should be no wires or sensors connected to the HEADER input if the boiler is operating as a member.
• Verify that the communication cables are of a shielded or twisted pair type. Shielding of the cable is required.
• Minimize possible electrical interference by routing the communications cables away from electrical noise sources, such as motors, ignition controls, contactors, etc.
Only the MASTER boiler Fires, but the system has many boilers and is using the Cast 92 Control.1. In order for the MASTER boiler to act as a MASTER1., the header sensor must be set to TYPEZ, and there must be a header sensor present.
2. At power-up, the header sensor is auto detected. If the temperature of the header sensor at power-up is greater than -25 °F and less than 240 °F it is considered a valid sensor. The boiler will default to the MEMBER mode if the temperature is not in this range, and can only be run locally or by external inputs.
3. The Cast 92 control needs a communications cable daisy-chained between boilers. Ensure that a good connection is made on the communications board and that the lights on the dual RJ45 jacks flash (roughly twice a second). The MASTER is the only one that should flash with no communications cables plugged in.
You get the error message - WATER FLOW SWITCH or WAITING FOR FLOW.1. If the control does not sense a closed circuit at input connection, FLOW SWITCH, check to make sure the circuit for the circulator pump is correct, that the pump is being energized, and that the flow prove switch is working properly.
2. If there is no flow prove switch, check to make sure that a jumper wire has been connected across the FLOW SWITCH terminals.
You have forgotten the password.Turn the ON/OFF switch off. Then depress and hold the ESC key while turning it back on. This will load the default password “AAAAAA".
Firmware update program starts to load, but then stops.Ensure that the USB driver for your PC/Laptop computer is properly installed.

Peerless GM series boiler troubleshooting

Burners not functioning.1. No power.1. Check line voltage wiring and fuses.
2. Limit (Aquastat) not working.2. Check wiring and contacts, relay, temperature setting. Clean and adjust as necessary.
3. Flame rollout switch open.3. Replace switch. Locate cause and correct.
4. Blocked vent switch open.4. Reset blocked vent switch. Locate cause and coned.
5. Gas off at boiler gas valve.5. Start boiler using Lighting/Operating Instructions.
6. Gas off external to boiler.6. Check any gas valves in the line.
7. Plugged orifice spuds.7. Check, clean and re-install.
8. Defective gas valve.8. Use Figure 9.1 to troubleshoot intermittent icpiition gas valve. Replace if necessary.
9. Improper wiring.9. Check and correct in accordance with wiring diagrams in Section 6.
10. Vent damper malfunctioning.10. Refer to vent damper manufacturer's instructions. Replace if necessary.
Burners will not shut down.1. Defective gas valve.1. Use Figure 9.1 to troubleshoot intermittent icpiition gas valve. Replace if necessary.
2. Short circuit.2. Check and correct wiring.
Flashback or burning at orifice spuds.1. Manifold gas pressure too low.1. Adjust to proper pressure.
2. Improperly sized/drilled orifice spuds.2. Install correct spuds.
3. Leaking gas valve.3. Replace valve.
4. Burrs on orifice.4. Remove burrs.
5. Low supply gas pressure.5. Contact gas supplier.
6. Excessive downdraft or draft problems in boiler room.6. Check air supply, ventilation and venting system.
Delayed ignition.1. Insufficient pilot flame.1. Increase pilot gas flow.
2. Riot bumer/orifice dogged.2. Clean pilot burner and orifice.
3. Overfiring.3. Reduce rate to input on rating label.
4. Misaligned burners or pilot.4. Realign burners or pilot.
5. Draft problem in boiler room.5. Check air supply, ventilation and venting system.
Excessive condensation in vent.1. Underfiring.1. Increase rate to input on rating label.
2. Limit (aquastat) set too low.2. Reset limit (aquastat) to higher setting
3. Vent pipe too long.3. Reposition boiler to reduce length.
4. Inadequate chimney or venting system.4. Check chimney and venting recommendations.
Boiler not heating properly.1. Underfiring.1. Increase rate to input on rating label.
2. Limit set too low.2. Reset limit (aquastat) to higher setting
3. Air in system.3. Vent air from all points in system.
4. Circulator malfunctioning.4. Check circulator, replace if necessary.
5. Circulation system dogged.5. Shut down and cool boiler, drain and flush system.
6. Incorrect thermostat heat anticipator setting.6. Adjust heat anticipator.
Fumes or gas odors1. Leaks in gas piping or fittings.1. Locate and repair or replace.
2. Leaks in gas service line or meter.2. Shut down boiler and notify gas provider.
3. Obstructed chimney.3. Check, repair anchor clean chimney.
4. Obstructed flueways or vent.4. Clean flueways or vent and remove obstructions.
5. Undersized chimney or vent, high draft loss in vent.5. Check National Fuel Gas Code ANSI Z223.1/NFPA 54 and/or CAN/CGA B149 Installation Codes and vent manufacturer’s recommendations.
6. Draft problem in boiler room.6. Check air supply, ventilation and venting system.
7. Overfiring.7. Reduce rate to input on rating label.
8. Vent damper malfunctioning.8. Refer to vent damper manufacturer's instructions. Replace if necessary.

Peerless PO-70 boiler troubleshooting

The boiler does not run and the control screen is blank.1. Make sure that 120 VAC power is present at Terminals L & N in the control panel.
2. Make sure the boiler service switch is switched on.
The boiler does not run and the control screen is on.1. Check if the ”Dem" segment is visible on the control display. This indicates that the control is getting a demand from either the thermostat or the DHW tank.
2. Check for the burner symbol on the control display. This symbol indicates that the temperature control is calling for the burner to operate.
3. Check indicator light on the Burner Primary control.
a. If it is on, it is detecting light, connections are shorted or the cad cell or control is
defective. Shield cad cell from light source.
i. If the indicator light goes off, eliminate the external light source or permanently shield the cad cell.
ii. If the indicator light stays on, replace cad cell. If indicator light does not turn off, remove cad cell lead wires. If light goes off replace cad cell bracket assembly. If indicator light does not turn off, replace controller.
b. If it is off, jumper the limit terminal and LI.
i. If the burner starts, check the limit circuit (See Step 4).
ii. If the burner doesn’t start, disconnect line voltage power by turning off the service switch. Check all wiring connections. Tighten any loose connections and recheck. If burner still doesn’t start, replace the primary control
4. Check the boiler water temperature gauge. If the boiler water is above 210°F check boiler circulator operation. Be sure that all air is purged from the system.
5. Depress the vent temperature limit reset button. Check all wiring in the limit circuit.
The burner starts, and then locks out on safety with indicator light flashing.1. Check that limit switches are closed and contacts are clean.
2. Check for line voltage power at the oil primary control. Voltage should be 110 VAC to 130 VAC.
3. Reset primary control by pushing in and releasing the red reset button.
a. If the indicator light stops flashing go to step (4).
b. If the indicator light continues to flash, verify that the primary control is not in restricted mode. If not in restricted mode, replace primary control.
4. Burner will re-try for ignition. Listen for spark after burner turns on (after 2 second
a. If there is no spark, check for line voltage at the igniter terminals, if line voltage is present, replace the igniter.
b. If there is a spark, check to see if oil is being sprayed into the combustion chamber. If there is no oil, check oil valve, oil valve wiring, pump and oil supply.
5. Check indicator light after the flame is established but before the oil primary control
locks out.
a. If the indicator light is on until the control locks out and starts flashing during lockout, replace the primary control.
b. If the indicator light stays off, go to step (6).
6. Check cad cell sighting for view of the flame.
a. Turn off the service switch on the front of the boiler
b. Unplug cad cell and clean the face with a soft cloth. Check the sighting of the cad cell for a view of the flame.
c. Re-install cad cell and turn on the service switch.
d. Re-start burner.
7. If the burner locks out check the cad cell.
a. Turn off the service switch on the front of the boiler.
b. Replace cad cell and disconnect jumper from t-t terminals on primary control to assure that no call for heat is present.
c. Turn on the service switch. Expose the cad cell to a bright light such as a flashlight.
i. If the indicator light is on, re-install control and go back to step 3.
ii. If the indicator light is off, go to step 8
8. Check the cad cell bracket assembly
a. Turn off the service switch on the front of the boiler
b. Remove cad cell leads from the primary control and leave the control lead wires open. Turn on the service switch. Place a jumper across the cad cell terminals after the burner motor turns on.
i. If the indicator light is on, replace the cad cell bracket assembly.
ii. If the indicator light is off, replace the primary control.
Burner runs with poor combustion, #1 or higher smoke spot.1. Check CO2 Level. If the CO2 has increased or decreased beyond the recommended 11.0% to 13.0% CO2 then adjust the air damper to correct the problem.
2. Check the oil supply piping for leaks.
a. Air leaks can cause excessive smoke and poor combustion. These may or may not be made evident by fuel leakage. Assure that all joints have been properly sealed.
b. Check the fuel filter fittings and gaskets for proper sealing.
3. Connect a dear polycarbonate hose to the fuel unit’s bleed connection. Position a container to receive the fuel at the end of the bleed hose. Observe the oil in the container for air bubbles or evidence of water. If there is evidence of air bubbles, re-check the supply piping for leaks.
4. If there is no evidence of air or water in the fuel line, replace the oil nozzle. The nozzle is to be replaced only with the nozzle recommended in Section 5, Oil Burner Installation or as recommended by the Factory.
Oil nozzles are inexpensive; however they are critical to the operation of the boiler. They should be kept in their protective sleeve, away from dirt and debris until ready to install. It is a good idea to have an extra nozzle in case of problems.

Error codes and troubleshooting