Chromalox PQ402-6 service manual Typical Malfunctions & Proper Correction

SERVICE MANUAL

Chromalox Electric

Steam Boilers

4	CES
(Supersedes PQ402-5)	PQ402-6

161-049460-001

FEBRUARY, 1999

The troubleshooting of Chromalox electric boilers can best be placed into five major areas. These areas are: (1) fusing (2) con- tacts, elements and voltages (3) pressure control (4) low water cut- off (5) water feed mechanism.

WARNING: Hazard of Electric Shock and Thermal Burns. These troubleshooting checks should only be performed by qualified personnel after review

of the Installation and Operating Instructions for your specific Chromalox Electric Steam Boiler.

For convenience, we have outlined a brief description of typical malfunctions and the area that should be explored in order to make the proper correction. This is followed by a detailed analysis of the five areas listed above.

TYPICAL MALFUNCTIONS & PROPER CORRECTION

Boiler does not heat:

1.Check power fusing.

2.Examine control circuit fuse.

3.Reset button on the Low Water Control must be depressed (for states requiring a reset button).

4.Float valve in the Low Water Control is not functioning prop- erly.

5.Elements and/or contactors faulty.

6.Mercury tube in Low Water Control has cracked and mercury has escaped.

Boiler takes too long to reach operating pressure or does not maintain desired pressure:

1.Check amperage on each supply leg of power harness. Reading should correspond to a rating of not less than 10% of rated boil- er amperage.

If considerable difference exists:

A.Available voltage is insufficient for boiler needs.

B.Heating element failure has occurred.

C.Fibre carrier in contactor requires replacement. On multi contactor units, check contactors and coils to determine if one is defective.

2.Check to determine whether boiler selected is underrated for the application.

3.Additional Equipment added after initial installation, thus undersizing boiler.

4.Steam piping not insulated.

Boiler continuously blows power fuses:

1.External fusing is not sized properly. Correct sizing is next size larger than boiler rating.

2.Check lines between element and contactors with an ammeter for uniform readings.

3.Check for evidence of charring which indicates loose connec- tions.

4.A short circuit exists in the boiler.

Boiler does not fill with water automatically or does not maintain constant pressure:

1.Check water supply line for closed valves.

2.Check power fusing.

3.For boiler without motor and pump assembly: check pressure of water supply to insure that it is consistently a minimum of 10 psi greater than the desired boiler operating pressure.

4.Check water inlet check valve.

5.For boiler with motor and pump assembly: check mercury tubes in the Low Water Control.

6.A. Check motor and pump for binding and over

heating. If caught in time, this can be observed by a humming sound. Replace if defective.

B.Check for defective solenoid valve.

C.Make sure pump is running with correct rotation.

D.Check impeller adjustment on turbine type pumps.

Boiler appears to be leaking from beneath the jacket:

1.Check boiler fittings for looseness; tighten as required.

2.Check boiler fittings for cracks; replace as necessary.

3.Examine heating elements around boiler flange.

IMPORTANT: Leaking is a hazard, correct to prevent further damage to other components.

Boiler overflows:

1.Float valve on the Low Water Control is stuck in the down position.

2.Solenoid valve is not operating.

3.Check for defective mercury tube on the Low Water Control if boiler has a motor and pump assembly.

Pressure increases beyond the preset limits causing safety valve to blow:

1.Check bellows in the pressure control.

2.Check for clogged syphon tube.

3.Contactor points have fused.

4.Check pressure control setting against safety valve rating.

Manual reset button needs constant resetting (for states requiring reset buttons only):

1.Boiler is not level; relocate if necessary.

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