Rapid 2005 Installation, Operation & Service Manual Download

Page: 153 / 162

SECTION 22: T

ROUBLESHOOTING

143 of 147

FIELD TEST

REMEDY

1. Arrow on side of valve should point in direction of gas fl ow.

1. Install properly.

2. Remove wires connected to amplifi er terminals 6 & 7 and mea-
sure resistance. MR212 (60-80 ohms), M611 (45-55 ohms).
3. Inspect - plunger should be installed per Maxitrol product infor-
mation sheet and operate freely in solenoid sleeve.
4. Disassemble valve for inspection of internal parts.

2. If proper resistance values are not observed, replace modulator head or
repair wiring.
3. Clean or replace plunger if necessary and install per Maxitrol product infor-
mation sheet.
4. Replace diaphragm if ruptured.

5. Check for 24VAC at amplifi er terminals 8 & 9.
6. Measure resistance per item 2.
7. Remove wires connected to amplifi er terminals 1, 2, & 3. Mea-
sure resistance across wires 1 & 3, then 2 & 3. Meter should read
greater than 2500 ohms.
8. Follow procedures outlined in “PRELIMINARY CIRCUIT ANALY-
SIS” (Sections I & II) in Maxitrol product information sheet.

5. Provide 24VAC to amplifi er. Refer to item 24.
6. If proper resistance values are not observed, replace modulator head or
repair wiring.
7. If readings are incorrect, replace the TS144 or repair wiring.
8. If power source and modulator coil check out (items 5 & 6) but proper modu-
lating voltages cannot be obtained, then amplifi er may be assumed at fault.
Install replacement amplifi er.

9. See Valve Adjustments - Section 19.5.
10. Measure manifold pressure as outlined in Section 19.4.

9. Adjust to proper low fi re.
10. If greater than 1.0 in wc negative pressure, check equipment for clogged
fi lters & other inlet air restrictions. For other solutions, consult factory.

11. Follow procedures outlined in “PRELIMINARY CIRCUIT ANALY-
SIS” (sections I & II), in Maxitrol product information sheet.
12. Remove wires connected to amplifi er terminals 4 & 5. Set T244
or TD244 to maximum setting. Measure resistance across wires.
Meter should read 6000 ohms +/- 1000 (T244). If TS244/TD244 are
used, meter should read 4500 ohms +/- 1000 (TS244) and 2100
ohms +/- 150 (TD244).
13. Follow procedures outlined in “PRELIMINARY CIRCUIT ANALY-
SIS” (Sections IV), in Maxitrol product information sheet.

11. If amplifi er is proven at fault, install replacement amplifi er.
12. If reading is incorrect, replace the T244, TS244/TD244 or repair wiring.
13. If proper action is obtained, fi rst check item 12. Recalibrate if necessary
See section 19.7.

14. Compare sensed temperature reading at TS144 with average
discharge air temperature.
15. Follow procedures outlined in “PRELIMINARY CIRCUIT ANALY-
SIS” (Sections IV), in Maxitrol product information sheet.

14. Move TS144 to location where average temperature can be sensed.
15. If proper temperatures are not observed, refer to temperature calibration
procedures, in Maxitrol product information sheet.

16. Remove button Plate and inspect valve and seat
17. Inspect - plunger should be smooth and clean and operate
freely in solenoid sleeve.

16. Clean, replace valve and/or seat if necessary.
17. Clean, or if necessary, replace plunger.

18. Measure resistance per item 7.

18. If readings are incorrect, replace the TS144 or repair wiring.

19. Read inlet pressure at valve, using a manometer with heater
operating at full fi re. Pressure should be at least equal to the sum
of: outlet pressure setting and pressure drop of the valve (See Max-
itrol Capacity Chart Bulletin) plus 1.0 in wc.
20. Read outlet pressure using manometer and compare with
recommendation of equipment manufacturer.

19. Increase inlet pressure if possible or change to larger valve. Consult factory
about possibility of using special spring to reduce pressure drop on selected
installations.
20. See valve adjustments in section 19.5.

21. Follow procedure outlined in “PRELIMINARY CIRCUIT ANALY-
SIS” (Sections I & II), in Maxitrol product information sheet.
22. Measure resistance per item 12.
23. Follow procedures outlined in “PRELIMINARY CIRCUIT
ANALYSIS: (Section IV), in Maxitrol product information sheet.

21. If amplifi er is proven at fault, install replacement amplifi er.
22. If reading is incorrect, replace the T244, TS244/TD244 or repair wiring.
23. If proper action is obtained, fi rst check item 22. Recalibrate if necessary.
Refer to Temperature Calibration Proceedures in Maxitrol product information
sheet

24. Measure resistance per item 2.

24. If proper resistances are not observed, replace modulator head or repair
wiring.

25. Check to see if heater is delivering air at maximum discharge
air setting.
26. Check to see if heater is delivering air at maximum discharge
air setting.
27. Check to see if heater is operating at high fi re.
28. Place thermometer next to T244 or TS244. Compare space
temperature reading with T244 or TD244 dial setting.

25. If desired temperature is not reached, increase maximum discharge air
temperature setting.
26. If desired space temperature is not reached, decrease minimum discharge
air temperature setting.
27. If desired space temperature is not reached with heater at high fi re, it may
be undersized. Consult manufacturer.
28. If temperature reading is incorrect, check items 25, 26, & 27, then recalibrate
if necessary.