ICM Controls ICM253 Adjustable Fan Delay Timer | Post-Purge Off Delay Control | 12–390 Second Adjustable Delay | 18–30 VAC | UL Recognized HVAC Blower Fan Control Board for Efficiency & Comfort

It's a very useful device. It allows me to make the fan on the central air continue running for a short while after the compressor ends its cycle; otherwise, they both stop when the thermostat setpoint is reached. The range for the delay is anywhere from 12 to 390 seconds. Anecdotally, I have already seemed to have found that it reduces the loss of cool temperature into the encapsulated crawl space. Now I just need to determine how long to run to purge the conditioned air through the system.

Delay on break 24v relay timer . Installed on signal side of Hvac blower relay to trick the relay into thinking the Wall Thermostat was still outputting “ Blower ON “ signal keeping the blower running after the Thermostat has already turned off the blower relayBasically turns your regular Blower Relay into a time delayed solid state relay . They call it delay on break ( so when Wall thermostat switches off this timer sees the “ break “ & then applies constant voltage back to the blower relay mimicking “ ON “ signal from Wall thermostat )Follow downloadable manual instruction PDF for this model delay timer ( follow diagram exactly )If wired correctly your splicing it into the 24v Transformer in the Hvac Air handler so it can mimic the 24v signal from the Wall Thermostat when turned off ( for the exact time you’ve got the delay set on with the knob )Used this to leave the Blower running 30 seconds after the unit is signaled off from Thermostat so the Heat Elements could cool off before blower turns offThere are Wall Thermostats out there like Honeywell Pro WiFi @ Zwave that have this feature under “ Advanced Setup “ menu , but there 5x’s the price of this

I installed the ICM253 Fan Delay Timer to help with short cycling on my HVAC system, and it does exactly what it’s supposed to. The delay function helps the fan run a bit longer after shutdown, improving efficiency and airflow.Installation was fairly straightforward, but I’d recommend double-checking the wiring instructions—it’s easy to mix up connections if you’re not careful. Once set up, though, it works flawlessly.Overall, a solid upgrade for HVAC efficiency, just take your time with installation!

My furnace has a built-in delay that keeps the fan running for 60 seconds after the call for cooling ends (as do some electronic thermostats), but I knew there was still a lot of cooling remaining in the evaporator coil if I could only run the fan a little longer.So I installed this little gem on my furnace and set it for its stated maximum of 390 seconds. (The actual delay it delivers is closer to 410 seconds, but I’m not going to quibble.)This relay does exactly what I expected it to do, and at a very attractive price point.The main benefits to me in the dry Colorado climate are:- increases humidity in the house during the cooling season (since much of the humidity remaining on the coil at the end of the cycle is returned to the house instead of going down the drain)- dries the evaporator coil after each cooling cycle making it less likely to get moldy or grow bacteria- improves efficiency of the A/C by extracting more cooling from the electricity used.Wiring was pretty straightforward (but I’m an engineer). The device is installed in series between the G (fan) wire coming from your thermostat and the G terminal on your furnace, but also needs Common and Hot 24 volt connections from the furnace. It also requires the use of “disconnect F” quarter-inch tab connectors and a crimper.Unless you are already skilled with low-voltage furnace wiring or really good at reading wiring diagrams, to avoid damaging your furnace or yourself, I recommend you get a pro (or a skilled friend) to help with the install.

Works as intended--the fan still runs ON SELECTED TIME after the condenser turned off from outside.I set mine to about 2 minutes after the thermostat cuts off the A/C.Installation:Like the diagram on the ICM253 unit.--1 and 4--bypass (undo and reconnect) the current GREEN wire from the Fan (1) and the GREEN wire from the thermostat (4)--2 and 3--tap (add into existing) into the 24vac from the RED (2) and BLUE/common/neutral (3) wiresI did not see the BLUE/COMMON/NEUTRAL 24vac wire once the furnace was opened.The wire diagram makes no sense at all !!!Google and YouTube did not help.So I removed the two screws and take out the cover that protected/covered the wirings and the 24v transformer (besides the breakers).I look for the 24v transformer and its Common/Neutral wire---It has wires out for the 24vac and wires in from the 240vac (labeled on the transformer...see picture).I saw the 24vac Common/Neutral wire (gray colored on this wire).I also saw that it was connected to the condenser outside...I simply tapped into that gray colored wire and done.Hope it helps someone out a bit.Have a great day.

Mine didn't work, and being's I waited till this spring to install, the warranty had expired. I thought it was year but it's only a month. Ordered another, which is working fine.