Aprilaire model 800 TROUBLESHOOTING Guide, Troubleshooting Guide, Problem, Possible cause, Action

TROUBLESHOOTING Guide

If a problem arises with the Aprilaire Model 800 Steam Humidifier, please review the following troubleshooting guide for possible causes and solutions.. If the problem persists, call Aprilaire Tech Support toll-free at 1-800-334-6011.. Please be prepared to describe the exact nature of the problem..

TABLE 5 – Troubleshooting Guide

Problem

Possible cause

Action

Humidifier does	No power to humidifier	• Check main power supply.
not energize; steam		• Check main line safety switch.
canister does not		• Verify terminal block electrical connections.
heat up, display
		• Verify humidifier is turned on.
lights not on
	No power to low voltage	• Check for proper supply voltage.
	control circuit	• Verify terminal block electrical connections.
		• Check for control circuit voltage, 24 VAC.
	Control terminals	• Check if auxiliary limit controls are not allowing system to operate, e.g., high limit
	are open	humidistat, airflow proving switch, etc.. Reset, replace, or calibrate as needed..
	ADHC faults:	• Check terminals for 24 VAC.
	• Open, shorted,	• Check control circuit wiring.
	or incorrect wiring
	of control
Steam canister failure	Improper wiring	• Verify proper electrical connections.
	Mineral buildup	• Inspect steam canister for severe mineral buildup on or around electrodes. If severe
	on steam canister	mineral buildup is present, replace steam canister..
	electrodes
	Steam canister electrode	• Inspect electrodes for surface corrosion or pitting. This is usually caused by a high
	corrosion	chloride level in the supply water.. Replace steam canister..
Unit does not fill	No water supply to	• Verify that manual water supply valve is open and that pressure exists.
with water	fill valve	• Check if in-line strainer in inlet port of fill valve is plugged. Clean strainer or replace.
	Unit control is not on	• Press On/Off switch.
	Malfunctioning fill valve	• If fill valve does not open:
		– Check for obstruction in valve..
		– Verify fill valve electrical connections..
		– Verify proper 24 VAC to fill valve.. If voltage is present and valve does not open,
		replace valve..
	Drain valve is open	• Check for obstruction in drain valve.
Fill valve does	Malfunctioning level	• Check that high water sensor electrical plug is fully engaged.
not close	control system
	Fill valve is stuck	• Check if there is an obstruction that does not allow valve to seat properly. Clean or
		replace valve as needed..
	Drain valve is open	• Clean or replace drain valve if an obstruction in the valve does not allow complete
		closure..

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