Coleman EB15B intermittent auto fan problem

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ferret13sj
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Tue Jan 25, 2011 2:49 pm

Sorry for this long post, but I want to include any details that might be helpful. My first post on the forum and I have read several similar topics that point to the sequencer, but I would like to be sure.

I have an electric Coleman EB15B. It's a combo unit with the A/C coil on top.

The thermostat is a digital Hunter, about 5 years old. The manual said to leave it set on HG for all furnaces, as long as it would operate the electric furnace correctly, and it has been set that way since installed. (Manual said that HE is only required for certain electric furnaces that won't run under HG.)

A few weeks ago the blower quit coming on automatically, coils were getting hot but no fan. I could turn the blower on manually and it would work. So the repairman came by and the first thing he did was switch the thermostat over to HE. In that setting the fan did kick on automatically, so he tested a few things, said it might be a sticky sequencer, told me to keep an eye on it, and he left. (Didn't charge me anything at least!) A couple hours later after re-reading my thermostat manual, I switched it back to HG, and it was working again on that setting. 3 days later, it quit, so I put the thermostat back on HE, and it fired right up. Again I switched it back to HG after a few hours, and it has been working fine for about 2 weeks. This morning it was back to heating up, but no blower coming on, so I've switched it again to HE and it's working, but please read my concerns below...

What I've noticed and would like some clarification on....in HE it turns on the blower as soon as the thermostat calls for heat. Under HG there is a few seconds delay which allows the coils to heat up, before the blower kicks in. When running under HE, it seems to take alot longer for the house to warm up enough to shut off the furnace. Is it working in HE because it's skipping some important step, making the blower come on as soon as the thermostat calls for heat? Possibly running the fan at a higher speed and not giving the coils a chance to heat the air well?

I found the info in another post for testing the sequencer and these are my readings. I did these tests with the thermostat on HG, coils heating up but blower not coming on automatically.

H1/H2=27.1 vac
H3/H4=27.1 vac
M1/M2= 249 vac
M3/M4= 249 vac
M5/M6= 0 vac

From this I'm assuming I need a new sequencer. I saw in another post to locate the 3 spade terminals on white ceramic bases. I found these I believe just below left of the sequencer (outlined in red in the attached picture). I tried testing them at the same time as the above test (with coils heating but no auto blower working, one probe on terminal, one to metal ground). The readings were 0 on each one, but then seemed to jump to 249 occasionally. Can you clarify if I'm doing this test right, or if I even need to be testing these terminals?

Any help you could give would be appreciated. I'm pretty good with DIY repairs, so if this is something I can fix myself, it would be great to avoid paying a repairman! Thanks in advance!
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Robert
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Tue Jan 25, 2011 5:22 pm

Hi,

Sequencer is definitely bad.

Sequencer # 3115 - 3571 can be seen and ordered from here by paging down:

http://www.aberdeenhomerepair.com/store ... -sequencer


I would suggest replacing the Hunter t-stat with a Honeywell. IF you choose to remain with the Hunter, leave it set to HG and don't be surprised if it gives future problems, they often do.


Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?

ferret13sj
Posts: 9
Joined: Tue Jan 25, 2011 1:59 pm

Tue Jan 25, 2011 6:36 pm

Thanks for your quick response. Yes my repairman frowned at the Hunter thermostat too, but he's the one who told me a few years ago to just "pick up a digital thermostat anywhere" because he didn't have one with him. I guess he forgot to tell me not to buy a Hunter! The thermostat isn't what makes the sequencer go bad though, is it? Or do you mean it will cause other problems on down the road?

On those 3 terminals I circled, does it sound like I tested those right and the results help confirm the sequencer is bad? Just curious...

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Robert
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Tue Jan 25, 2011 7:39 pm

Hi,

The t-stat itself will often cause problems. Great ceiling fans, but not t-stats.


The sequencer test itself was all that was needed.


Thanks,
Robert
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ferret13sj
Posts: 9
Joined: Tue Jan 25, 2011 1:59 pm

Tue Jan 25, 2011 8:15 pm

Robert wrote:Hi,
Great ceiling fans, but not t-stats....


Thanks,
Robert

Good to know, I've hung alot of Hunter ceiling fans!

Just finished watching the video on how sequencers work. Very informative. Nice to see so much information before purchasing a part. Are you the owner of Aberdeen and is it basically the same as ordering from mobilehomerepair.com? I noticed the prices are the same through both websites, but shipping and checkout were different.

I found the part for less somewhere else, but I feel like your support and added information is well worth the extra cost. I will be ordering here. Thanks again!


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Robert
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Tue Jan 25, 2011 8:44 pm

Hi,

This website, online store and the aberdeenhomerepair.com store are all owned by Mark Bower.

I do contracted work for him on here and through emails.



Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?

ferret13sj
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Joined: Tue Jan 25, 2011 1:59 pm

Tue Jan 25, 2011 9:11 pm

Well you're doing a great job. I expected to wait a day or two for a response, but you are right on top of things. Thanks again!

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Robert
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Wed Jan 26, 2011 5:30 am

You're very welcome, happy to help.



Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?

ferret13sj
Posts: 9
Joined: Tue Jan 25, 2011 1:59 pm

Tue Mar 01, 2011 11:47 am

Finally got around to installing my sequencer and new thermostat. The blower now comes on within a few seconds of the thermostat calling for heat, and I can hear the 1st coil click on right as the blower starts (not a few seconds before like it used to). The other 2 coils come on within 30-45 seconds after that. Does it sound like the sequencer is working correctly at the right intervals? Is the first coil supposed to start with the blower, or a few seconds earlier to allow warmup?

The thermostat I bought is a Honeywell RTH2310B, programmable. After messing with this thing, I realize I don't need a programmable since I don't have a set work schedule. Bought it at Lowes but they don't even show it on their website, so wasn't able to read reviews. The model they do show looks identical except it doesn't have a backlight, and it has alot of bad reviews about being unreliable, so I'm thinking about taking this one back and exchanging for the basic electronic non-programmable. Just wondering if you're familiar with this model and if you've also seen problems. The one I would exchange for is RTH5100B1009, if you have any experience with that one too. (I do have a single-stage furnace, correct?)

My last question, on the new thermostats they seem to be permanently set to keep the room temp within 1 degree of the set temp (all the Honeywells I looked at). My old one kept it within 2-3 degrees. I notice the furnace coming on alot more often now, several times within an hour, but it only runs for a few minutes at a time. Is it really more energy efficient to keep the temp within 1 degree? Doesn't this cause the parts to wear out sooner with more frequent starts?

Thanks again for your help on this!

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Robert
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Tue Mar 01, 2011 3:40 pm

Hi,

Some sequencers have a delay between coil and blower, some don't. When the top contacts close on yours, it sends power to coil and blower at same time.

The timings are correct on yours. You can install a timed delay if you want to delay the blower.


I don't buy t-stats from Lowe's, but have had no problems that I recall from that one.

I recommend Honeywell, White-Rodgers and RiteTemp. I do not care for Hunter or Lux t-stats.


Some t-stats have a built in heat anticipator and others have a manual set one.

That and other things can cause cycling problems.


You will pay more, but get better t-stats at an hvac supply store than at the big box stores.



Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?

ferret13sj
Posts: 9
Joined: Tue Jan 25, 2011 1:59 pm

Tue Mar 01, 2011 3:47 pm

We do have a large supply place in town, so I'll check that out instead. Just seems like those Honeywells being set on 1 degree difference is keeping my furnace too busy. I know Hunter is not a good brand, but at least mine did allow me to change that setting....

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Robert
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Tue Mar 01, 2011 4:04 pm

Hi,

IF your home is well insulated, the t-stat should keep it within +/- 1-2 degrees.


You set it where you want the temp to be and it should keep it there or very close.


Call the supply house first, they may or may not sell to the general public.



Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?

ferret13sj
Posts: 9
Joined: Tue Jan 25, 2011 1:59 pm

Tue Mar 01, 2011 5:54 pm

Robert wrote:
IF your home is well insulated, the t-stat should keep it within +/- 1-2 degrees.
Granted it's better insulated now with my new roof and Pella windows, but it's still a mobile home, LOL!

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Robert
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Tue Mar 01, 2011 6:30 pm

A mobile home can be just as insulated as any other home.






Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?

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