Heat Pumps and Electric Home Heating - Frozen Coil
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jeepgrady
04-06-08, 04:16 PM
Some of you may recall some of the many problems I've had with the HP installed in my new home.
Today, I figure since the a/c season is around the corner that I would try it out. Well, low and behold I have a new problem. It is a three zone Lennox x16 system and with one of the smaller zones only calling for the a/c, she shut down. The Harmony III board gave an error code reading: DAS sensed frozen coil. Based on what I read, if the discharge temp goes down to 45 deg. the comp. should shut off and the fan should continue until the temp reached 50 deg., assuming that there is still a cooling call. Then the comp. should start up again. Well, this didn't happen, thus the frozen coil.
Am I correct in assuming that there's a good chance that the DAS is defective? What would cause the coil to freeze up from the beginning. The o/d temp was only abou 75. Would this have caused it to freeze?
Today, I figure since the a/c season is around the corner that I would try it out. Well, low and behold I have a new problem. It is a three zone Lennox x16 system and with one of the smaller zones only calling for the a/c, she shut down. The Harmony III board gave an error code reading: DAS sensed frozen coil. Based on what I read, if the discharge temp goes down to 45 deg. the comp. should shut off and the fan should continue until the temp reached 50 deg., assuming that there is still a cooling call. Then the comp. should start up again. Well, this didn't happen, thus the frozen coil.
Am I correct in assuming that there's a good chance that the DAS is defective? What would cause the coil to freeze up from the beginning. The o/d temp was only abou 75. Would this have caused it to freeze?
Greenguy1
04-07-08, 04:02 AM
I think you would be safe to assume that the das is defective. The freezing is proportional to the amount of humidity, typically. How is your filter, is it new or clean?
Matt Gruber
04-07-08, 04:04 AM
sounds like a faulty sensor.
i use an infrared temp gun to point at the duct.
Hopefully others will chime in as i have no experience with your type system.
i use an infrared temp gun to point at the duct.
Hopefully others will chime in as i have no experience with your type system.
Ed Imeduc
04-07-08, 09:14 AM
Am I correct in assuming that there's a good chance that the DAS is defective? What would cause the coil to freeze up from the beginning. The o/d temp was only abou 75. Would this have caused it to freeze?
Here we go again You have had a post on this 3 zone set up before. Ill say the same thing. What you have there dont work. The unit is to big for the zones and zones in a home dont work. If you have a bypass damper in the duct that you should have there. It just lets the cold air back to the coil and ice up. You have to get more of that air off the coil. 4 ton thats 1600 CFM. So if you dont let it out ,the coil will ice up. To save what you have there now. Set it up as one zone. Play with the zone dampers that you have in the duct now. You can balance the home better that way. Run the unit off one tstat.:wall:
Here we go again You have had a post on this 3 zone set up before. Ill say the same thing. What you have there dont work. The unit is to big for the zones and zones in a home dont work. If you have a bypass damper in the duct that you should have there. It just lets the cold air back to the coil and ice up. You have to get more of that air off the coil. 4 ton thats 1600 CFM. So if you dont let it out ,the coil will ice up. To save what you have there now. Set it up as one zone. Play with the zone dampers that you have in the duct now. You can balance the home better that way. Run the unit off one tstat.:wall:
furd
04-08-08, 12:21 AM
I don't have a clue as to what a DAS may be but I agree with Ed. Zoning of residential forced air heating and cooling systems is a bad idea, often a very bad idea.
If your house is large enough that zoning is required then you need multiple units. The ONLY time I modify my thoughts on this is when it is a single room, small in relation to the entire system, that one wishes to control to a lower temperature in the heating cycle or warmer in the cooling cycle.
If your house is large enough that zoning is required then you need multiple units. The ONLY time I modify my thoughts on this is when it is a single room, small in relation to the entire system, that one wishes to control to a lower temperature in the heating cycle or warmer in the cooling cycle.
Greenguy1
04-08-08, 03:35 AM
I was assuming das was the frost sensing circuit, board or sensor.
jeepgrady
04-08-08, 09:17 AM
DAS= Discharge Air Sensor