distributation blower

[jerf]

I have a harmon p68 i use the stove in room temp on hi..i have temp set to 70 and the feed rate on 4.i also have the temp sensor for the room which is hung up by the stove.
Once my temp is reached shouldn't by distributation blower cut out and a small fire remain in the bowl.than when my temp drops below 70 the feeder feed fire get bigger and blower come on..This is what it use to do so i could control the temp of my room.

Now i get a big flame temp doesn't not get reconized and the blower continues till the fire goes out.once temp drops below 70 it starts the whole process again now i can't control the temp at all.
Any answers to why..

 

[tjnamtiw]

I don't have your stove but I do remember looking at them. Aren't you supposed to put the room sensor across the room?? Don't the instructions specifically tell you NOT to put it near the stove???

 

[imacman]

....Don't the instructions specifically tell you NOT to put it near the stove???

Actually, just the opposite, according to the P68 installation manual:

"In most installations locating the room sensor
behind the stove near the distribution fan works well
because the sensor monitors the room air being
drawn into the distribution fan."

 

[SmokeyTheBear]

You might want to clean your ESP and exactly where is your room probe in relation to the distribution blowers air intake.

 

[tjnamtiw]

....Don't the instructions specifically tell you NOT to put it near the stove???

Actually, just the opposite, according to the P68 installation manual:

"In most installations locating the room sensor
behind the stove near the distribution fan works well
because the sensor monitors the room air being
drawn into the distribution fan."

Live and learn! I could have sworn I saw a picture of it across the room from the stove. It makes sense, though, to put it right at the intake to the blower.

 

[imacman]

.....I could have sworn I saw a picture of it across the room from the stove......

You can....Harman says you can extend the wires up to 50' if you want, but recommend keeping it no more than 25'.

And placing it directly across the room isn't a great idea, as the hot air from the conv. blower will give the stove a false reading. I have my stat around a short corner in the kitchen, so hot air doesn't blow on it directly.

 

[SmokeyTheBear]

....Don't the instructions specifically tell you NOT to put it near the stove???

Actually, just the opposite, according to the P68 installation manual:

"In most installations locating the room sensor
behind the stove near the distribution fan works well
because the sensor monitors the room air being
drawn into the distribution fan."

Live and learn! I could have sworn I saw a picture of it across the room from the stove. It makes sense, though, to put it right at the intake to the blower.

There are several places that it can be mounted. It all depends upon where you want the set point to be measured at.

Having it in the return air (distribution intake) makes that set point measurement be of return air. It doesn't guarantee that some of the area doesn't go over that.

Most differences I've seen on here happen when the stove is measuring the floor temperature (tends to overshoot the set point) or almost in line with the blower output (tends to undershoot the set point). When a temperature reading (set point) is taken.

However the ESP has a very large part in how the stove reacts as the room temperature approaches set point.

 

[jerf]

Esp is clean and the probe is right behind my stove..
I had a new board put in and harmon told me that now the stove works by setting temp say 70 once the fire builds the blower will kick in and stay in till fire goes out..so a temp of 70 actually goes to about 75 to 80 because blower will not cut out..so what the since of a room themer if the temps goes higher .

 

[jerf]

one other thing even though i have a few coals in bowl when the fire starts up again igniter light comes on ..so in an hour say it comes on about 8 times or more..so that won't last long.

 

[SmokeyTheBear]

If I had a thermostat and was behind the stove I'd expect it to agree on temperature only at or near that location, which is exactly what happens with any thermostat what the temperature is at any other point in the room is likely to be different.

It is also possible that the boards dip switches were set differently between the old one and the new one and thus is contributing to the overshoot.

But temperature measurements and thermostats need to be taken very close to the same location to have any real meaning in relation to each other.

 

[SmokeyTheBear]

one other thing even though i have a few coals in bowl when the fire starts up again igniter light comes on ..so in an hour say it comes on about 8 times or more..so that won't last long.

The controller likely isn't seeing enough heat so it considers the fire to be out and thus it starts the igniter.

I'm sure there are other possibilities but that would be my first suspicion.

 

[SmokeyTheBear]

How about this, the ESP connections aren't tight or isn't the proper one for the new board.

This could explain both situations, I'd get on the phone to the folks who installed the new board and run that by them.

ETA: Let us know how things work out, I'm out of here for now.

 

[jerf]

thanks i will because the harmon tech wasn't any help at all

 

[LIpelletpig]

Try switching the ignitor switch to manual vs. auto. That allows the stove to go to an idle low burn without it going out and the ignitor having to restart the fire again when needed.

 

[SmokeyTheBear]

Try switching the ignitor switch to manual vs. auto. That allows the stove to go to an idle low burn without it going out and the ignitor having to restart the fire again when needed.

Also a very good idea as far as the igniter situation is concerned.

 

[jerf]

In manual the stove does not use ingnter.But you have to remember before the new board when in auto a small fire would remain in bowl and i could control temp of my room now i can not control temp of room..gets to cold or it gets to hot..and according to harmon this is the way the new board works and it will be in all new stoves..they also told me the manual that came with the stove is no good because of the new board..

 

[SmokeyTheBear]

In manual the stove does not use ingnter.But you have to remember before the new board when in auto a small fire would remain in bowl and i could control temp of my room now i can not control temp of room..gets to cold or it gets to hot..and according to harmon this is the way the new board works and it will be in all new stoves..they also told me the manual that came with the stove is no good because of the new board..

Did they provide you with a new manual?

Harman actually told you that or was it your local dealer's people?

Harman will rarely if ever talk to a customer.

 

[Delta-T]

there's a chance your new board was set incorrectly for your unit causing some confusion between the board, the ESP and the sensor probe. the new board doesn't do anything different from the old board if set up right. when your old board told the stove to turn down and keep a small fire going in "auto" sounds very strange to me. This would be normal if you switched to manual after the stove was lit, but it should have told the unit to slow down as it approached the set temp and to turn off if it overshoots. normal shutdown time of about 35-45 minutes would lead to a lil extra heat but nothing excessive IMO. if the stove senses a call for heat before it gets to shutdown it just re-engages everything and off it goes. I would take a look at the dip switches... how old is the unit? If before 2009, for P68 should read (from 1-8) on,on,off,off,on,on,on,on. While we are at it, why was your board replaced?

 

[SmokeyTheBear]

Thanks for dropping in Delta-T.

jerf I'm sure that Delta-T can help, he does this for a living.

 

[Delta-T]

instead of "sure" I can help, I'd say its closer to "make an effort"......I do my best, but I'm not perfect

 

[SmokeyTheBear]

instead of "sure" I can help, I'd say its closer to "make an effort"......I do my best, but I'm not perfect

Ok, but at least you have access to more information than I and a lot of others in this thread do.

 

[jerf]

i do believe it was set right

had a problem with the motor service guy came back and said it was a probe got all that replaced in the process he blew a fuse.
replaced a fused and the only time he could get the stove to work was playing around with the wire harness.
so they told him the board was gone.
than board got replaced and stove didn't work propley but when he jumped a wire that was hooked up tp my low pressure switch it worked
so now the yellow probe that was in my hopper is gone now there is a switch on my hopper that will get hit by the lid to say it is close and they had to drill and thread a hole in the back of the stove .
so a motor didn't work to where i am now.

I still think the old board will work because i do believe i had a short..

 

[jerf]

my stove is feb 2009 and the harmon guy said my manual is no good as in the manual page 15 last pargraph states about blower he told me that was no good know more because i had a new board

 

[Delta-T]

now we're gettin somewheres....ok. I still maintain that there should be no operational difference between the old board and the new, so your manual is still quite valid, though, the latest revision of the manual (available as a PDF) has much better pictures and cleaning instructions. Feb 09 build date puts your machine on the cusp....do you know if you have a PVC tube connecting your air intake assembly to the feeder body just above and to the right of where the auger passes through the unit? If so, you will have the Ultra-feed system and would require a different dip switch combination, (1-8) on,off,on,off,on,on,on,on. Other things that could be factors....your ESP probe wires..are they colored red or black? If red then #5 dip switch should be ON, and if not red, OFF. It is also possible that the short could mess with the room sensor in some way...only way to test that is with the handy-dandy DDM thingy...or get a new room sensor probe (relatively cheap). Do you get any strange operation from the stove temp mode or just odd temp swings in room temp mode?

 

[jerf]

yes i have the tube..the yellow probe that use to be in the hopper is now gone the switch that was installed the wire rnow runs down through the hole.Just above the feeder motor they had to drill and thread to put the new item in..but when that was done nothing was changed on the dip switch on the harness only time that was changed was when the new board was installed.