All installations and services must be performed by qualified service personnel.
No
After fuel valve opens, does the burner ignite?
For the GMD, measure gas supply pressure at inlet to gas valve. Is it at least 4.5" W.G. for natural gas or 11" W.G. for L.P. gases? For the OMD, is oil present in
the fuel line at the valve?
Yes
No
Check the fuel supply. Open all manual shutoff valves serving the unit.
Purge any air in the fuel line.
Yes
Are the ignition electrodes |
| No |
| Reposition to |
|
|
| ||
positioned correctly? |
|
| correct location. | |
Yes |
Check for blocked or severely worn burner nozzle (OMD) or burner orifice (GMD). Clean or replace as required.
Does the burner stay lit past proof of flame check?
Yes
No
Yes |
On the GMD, measure supply & |
| |
manifold pressures. Are they |
| |
constant over time and within the | No | |
allowable ranges? On the OMD, | ||
| ||
is the oil tank full of fuel? Is the |
| |
fuel clean without contaminates? |
| |
Is the fuel filter dirty? |
|
On the GMD, adjust supply pressure to 4.5" W.G. for natural & 11" W.G. for LP gases. Adjust manifold pressure to 3.5" W.G. for natural gas or 10" W.G. for LP gases. If gas pressure fluctuates, a pressure regulator may be required or gas piping may be too small for flow. On the OMD, add or replace fuel and fuel filter. Also, check flame sensor (GMD), cad cell (OMD) for proper operation.
Does the fan timer
energize the circulating air blower after the 56 second time delay?
Yes
No
Check settings on fan
timer against those
on connection
diagram. Is blower
still inoperable after time delay with fan timer set correctly?
Yes
Measure voltage on the circulating air blower terminals. Is it 120 VAC?
Yes
Does blower wheel
spin freely?
Yes
Is blower motor
capacitor functioning
properly?
Yes |
Replace motor
|
|
| Check wiring to |
| |
|
|
| blower. If okay, |
| |
No |
|
| set fan selector |
| |
|
|
| switch to manual. |
| |
|
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| If fan operates, |
| |
|
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| replace fan timer. |
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No | Check for blower wheel | ||||
| rubing against housing | ||||
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| or motor shaft spinning | |||
| freely. Adjust or replace | ||||
|
|
| as necessary. | ||
No |
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| |
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| Replace blower |
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|
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| motor capacitor. |
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