When heat comes on,Lights dim and stay dim until it shuts off.

[awilli]

In June 06 we bought a new Clayton 2300 sq. ft. double-wide to down size from the two story 18' ceiling 1922 era home we were living in. The HVAC system we have in this double wide is all electric, heat and air. We did'nt notice this during the summer with the A/C running, but since it has finally gotten cold enough here in the south for the heat to be used, everytime the heat comes on the lights in all of the house go dim. It's considerable dimming of all the lights and lasts until the heat goes off. I am no electrition by any means, I know there should be a brief dimming when the unit first comes on and then everything should come back to normal. but that's not happening. If anyone has any ideas please send them out to me. I don't know the brand of the unit right off my head right now, If anyone needs to know I can pull the panel off the return and get all the info. I just had this on my mind and its late so i didn't do it tonight. Besides I've got the oven door laid all out in the kitchen right now from another project. I can imagine what the wife would say if I started taking something else apart.

[AccApp]

Hopefully you have a package unit (A/C and heat pump all in one). Most likely the heat pump is not working and the electric resistance elements are coming on to bring the temp up. Sounds like you need a pro out there anyway, there is no way the lights should be dimming unless you have a real problem. Send some pics of what you have and someone might be able to help you.

[awilli]

No its not all one unit. I should have stated the heat is in the wall behind the return. The unit outside does not come on at all when the heat is on. another thing I meant to mention is my electric bill has been outrageous.MORE than TWICE what it was during the summer, and the air ran almost non stop. This thing is brand new! this was supposed to be one of the top of the line mobile homes. I will take some pics and send them out.

[AccApp]

It takes a lot more energy to produce heat with the house-sized "hair-dryer" than to steal it from the air inside and shove it outside. A properly running heat pump costs less to run in ~72°-35° outside temps because it is stealing heat from the outside air and shoving it into the house.

[awilli]

Your saying what I have is essentially an over sized hair dryer in the wall?So I should look into having the unit replaced with a "real" A/C-heat-pump? Come to think of it ,it realy didn't cool all that well this past summer either. But the electric bill was reasonable.

[hvacdrd]

AccApp is correct, you have an oversized hair dryer. Electric strip heat is typically the "emergency" backup (supplement) for a heatpump  when it is too cold outside  to operate efficiently(below 35) or when the heatpump has malfunctioned. Check the tstat switches & tell us what you have. For heat pumps the system switches are usually - Cool - Off - Heat - Emer - or something along those lines. You may want to contact your contractor to see what type of system you have ie. heatpump or A/C with electric heat only.

The lights dimming indicates a high draw on the electrical system causing low voltage at the main panel. Possible causes are poor wiring connections or too small of an electric service to your home.

[Keinokuorma]

If the elements are open to air coils, it is possible that some part of the coils has drooped and is touching another part of the coil. This would make it draw excess current.

[That Guy]

If there is something wrong with the elements it would trip the breakers. I'd say you have a serious electrical problem. Bad or poor ground, undersized breaker box or service to it. Have it checked out ASAP. Also your outside unit could be low on freon. thats why it didn't cool well and now doesn't heat right.

[Keinokuorma]

True, if there is enough excess draw to noticeably dim the lights constantly, the breakers would trip.

Conventional fused circuits could take up to 30% excess current for a long period of time... I have witnessed a 3kW water heating tank to run off a 230V, 10A circuit with slow-to-blow fuse for about an hour before blowing the fuse. No lights dimming though, so I bet you're dealing with weak power to the house, although it was noticed only now.

And That Guy is right, the heat pump is probably malfunctioning, and the electric heating kicks in because of that.

[Northern-Tech]

  Here are a few suggestions.

Take a load reading  on the unit itself. Is it within range of what is specified on the nameplate ? If above what is marked, then something could be wrong with the elements as others have stated. 

Pick a random receptacle. Use a digital multimeter, take a voltage reading across the hot / neutral pins ( not the round one, which is the ground ). Take the reading with the unit off. Now, start the unit and see what the difference is. In canada, general rule is not to go below 3%  voltage drop, in a branch circuit.  Probably the same, or close to this in the US. So if you have 120 volts, ( no load, ) and then start the unit....ideally you dont want to be less than ( 120V X .97  = 116.4 V ). If this happens in all the plugs........some things to check for.......remove the cover on the main panel ( shut the main breaker / switch off )...and look for overheated / loose connections.....ensure all connections are tight, especially on the breaker for the unit. Also check the connection on the neutral itself. Some weird and wonderful things will happen with loose neutrals......electricity will try and find a path somehow, someway. Good Luck !!         Be careful !!

[Keinokuorma]

It is not clear to me what kind of and especially how old house this is... if it's from 1920's (?) it might be iron or aluminum wired... could develop various trouble with hign loads.

I've lived in a narrowly post-WW2 house, where I couldn't recognize the wiring type for sure, but I knew it wasn't copper. Something greyish that formed a black residue, possibly aluminum, in retrospect. Anyway, that was mostly a pain for joining new wiring, much of the insulation crumbled at touch, as did some of the conductors too, so I ended up re-wiring everything completely.

[hvacdrd]

[user=20436]awilli[/user] wrote:

In June 06 we bought a new Clayton 2300 sq. ft. double-wide to down size from the two story 18' ceiling 1922 era home we were living in.

I'm just not clear if awilli has a heat pump or not...